By typing in your keyword : (Keyword can be a particular word, an author, a journal, etc.)
140 articles found

L0179 – Effect of mechanical stretching on electrical conductivity and positive temperature coefficient characteristics of poly(vinylidene fluoride)/carbon nanofiber composites prepared by non-solvent precipitation

Poly(vinylidene fluoride) (PVDF)/carbon nanofiber (CNF) composites with filler content ranging from 0.047 to 4.7 vol.% were prepared with non-solvent precipitation followed by melt compression. The morphology and electrical conductivity of the composites before and after mechanical stretching were examined. The results showed that CNFs were dispersed homogeneously in the PVDF matrix and a low electrical percolation threshold of 0.90 vol.% CNFs was obtained. Mechanical stretching led to a sharp decrease in the electrical conductivity of a composite containing 0.94 vol.% CNF. This was caused by the destruction of a conducting network structure when the fillers aligned along the stretching direction. This did not happen when the filler content was increased to 1.88 vol.%. The percolating composites displayed a positive temperature coefficient (PTC) effect with the effect being larger in stretched composites. This can be attributed to the presence of PVDF ?-phase in stretched composites as revealed by X-ray diffraction and Fourier transform infrared spectroscopy.
S.P. Bao, G.D. Liang, S.C. Tjong, Carbon 49 (2011) 1758-1768

L0178 – Microwave sintering of nano-sized ZnO synthesized by a liquid route

Zinc oxide is a widely used material in various applications in electronic, optic, and spintronic fields, in particular. The control of the final properties of ZnO requires the mastering of the final microstructure. To achieve this goal, the grain growth of ZnO has been examined as a function of the sintering conditions, in particular in using a specific microwave sintering method. In order to get nano-sized ZnO powder as a starting material, a liquid route was implemented. The latter is based on the direct precipitation of a zinc oxalate solution. After thermal treatment, pure ZnO powder was obtained with a very narrow grain size distribution, centered at around 20 nm. The sintering of this powder was then carried out in conventional and microwave furnaces. While an important grain growth occurs during the conventional sintering, it is shown that microwave sintering allows us to maintain the grain size at the nano-metric scale.
E. Savary, S. Marinel, H. Colder, C. Harnois, F.X. Lefevre, R. Retoux, Powder Technology 208 (2011) 521–525

L0177 – Enhancing strength and hardness of AZ31B through simultaneous addition of nickel and nano-Al2O3 particulates

In the present study, AZ31B–Al2O3–Ni composites are developed by the addition of different amounts of Ni particulates into AZ31B–1.5Al2O3 using disintegrated melt deposition technique followed by hot extrusion. The AZ31B–1.5Al2O3 nano-composite is known to exhibit excellent ductility (?30%) matching with that of pure aluminum but its strength levels are compromised. The composites developed in the current study show a homogeneous microstructure and significant improvement in mechanical characteristics. The results of mechanical properties characterization reveal that addition of Ni led to a simultaneous improvement in 0.2% YS (up to 25%), UTS (up to 13%) and hardness (up to 62%). The ductility, however, stayed almost similar to the ductility of monolithic AZ31B in the case of AZ31B–1.5Al2O3–1.5Ni composite while it was compromised for AZ31B–1.5Al2O3–3.19Ni. The results clearly reveal the superior capability of AZ31B–Al2O3–Ni formulations in terms of overall mechanical response when compared to monolithic AZ31B.
Q.B. Nguyen, K.S. Tun, J. Chan, R. Kwok, J.V.M. Kuma, M. Gupta, Materials Science and Engineering A 528 (2011) 888–894

L0172 – Reaction sintering of colloidal processed mixtures of sub-micrometric alumina and nano-titania

The fabrication of composites formed by alumina grains (95vol%) in the micrometer size range and aluminium titanate nanoparticles (5vol%) by reaction sintering of alumina (Al2O3) and titania (TiO2) is investigated. The green bodies were constituted by mixtures of sub-micrometric alumina and nano-titania obtained from freeze-drying homogeneous water based suspensions, and pressing the powders. The optimization of the colloidal processing variables was performed using the viscosity of the suspensions as control parameter. Different one step and two step sintering schedules using as maximum dwell temperatures 1300 and 1400°C were established from dynamic sintering experiments. Specimens cooled at 5°C/min as well as quenched specimens were prepared and characterized in terms of crystalline phases, by X-ray diffraction, and microstructure by scanning electron microscopy of fracture surfaces.Even though homogeneous final materials were obtained in all cases, full reaction was obtained only in materials treated at 1400°C. The microstructure of the composites obtained by quenching was formed by an alumina matrix with bimodal grain size distribution and submicrometric aluminium titanate grains located inside the largest alumina grains and at triple points. However a cooling rate of 5°C/min led to significant decomposition of aluminium titanate. This fact is attributed to the small size of the particles and the effect of the alumina surrounding matrix
M.I. Nieto, C. Baud?n, I. Santacruz, Ceramics International 37 (2011) 1085–1092

L0171 – Phase transformation kinetics of 3 mol% yttria partially stabilized zirconia (3Y-PSZ) nanopowders prepared by a non-isothermal process

A crystalline nanopowder of 3 mol% yttria-partially stabilized zirconia (3Y-PSZ) has been synthesized using ZrOCl2 and Y(NO3)3 as raw materials throughout a co-precipitation process in an alcohol–water solution. The phase transformation kinetics of the 3Y-PSZ freeze dried precursor powders have been investigated by nonisothermal methods. Differential thermal and thermogravimetric analyses (DTA/TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution TEM (HRTEM) have been utilized to characterize the 3Y-PSZ nanocrystallites. When the 3Y-PSZ freeze dried powders are calcined in the range of 703–1073 K for 2 h, the crystal structure is composed of tetragonal and monoclinic ZrO2. The BET specific surface area of the 3Y-PSZ freeze dried precursor powders calcined at 703 K for 2 h is 118.42 m2/g, which is equivalent to a crystallite size of 8.14 nm. The activation energy from tetragonal ZrO2 converted to monoclinic ZrO2 in the 3Y-PSZ freeze dried precursor powders was determined as 401.89 kJ/mol. The tetragonal (T) and monoclinic (M) ZrO2 phases coexist with a spherical morphology, and based on TEM examination have a size distribution between 10 and 20 nm. When sintering green compacts of the 3Y-PSZ, a significant linear shrinkage of 8% is observed at about 1283 K. On sintering the densification cycle is complete at approximately 1623 K when a total shrinkage of 32% is observed and a final density above 99% of theoretical was achieved.
Chih-Wei Kuo, Yun-Hwei Shen, Shaw-Bing Wen, Huey-Er Lee, I.-Ming Hung, Hong-Hsin Huang, Moo-Chin Wang, Ceramics International 37 (2011) 341–347

L0164 – Anode-supported microtubular cells fabricated with gadolinia-doped ceria nanopowders

Anode-supported microtubular SOFCs based on ceria 3 ± 0.2 mm diameter and about 100 mm in length have been prepared using gadolinia-doped ceria (GDC) nanopowders. Nanometric Ce0.9Gd0.1O1.95 (GDC) powders were deposited on NiO–Ce0.9Gd0.1O1.95 (NiO–GDC) anode supports by dip-coating technique. Fabrication conditions to obtain dense and gas tight electrolyte layers on porous microtubular supports were studied. Three different dispersing agents: commercial Beycostat C213 (CECA, France) and short chain monomer (?4 carbon atoms) with alcohol or carboxylic acid functional groups were evaluated. By optimizing colloidal dispersion parameters and sintering process, gas tight and dense GDC layers were obtained. Significantly lower sintering temperatures than reported previously (?1300 °C) were employed to reach ?98% values of theoretical density within electrolyte layers of ?10 ?m in thickness. A composite cathode, LSCF–GDC 50 wt.% with about 50 ?m thickness was dip coated on the co-fired half-cell and then sintered at 1050 °C for 1 h. The electrochemical performance of these cells has been tested. In spite of electronic conduction due to partial reduction of the thin-electrolyte layer, the I–V measurements show power densities of 66 mW cm?2 at 0.45 V at temperatures as low as 450 °C (using 100% H2 as fuel in the anodic compartment and air in the cathodic chamber).
V. Gil, J. Gurauskis, R. Campana, R.I. Merino, A. Larrea, V.M. Orera, Journal of Power Sources 196 (2011) 1184–1190

L0160 – Development of new magnesium based alloys and their nanocomposites

In the present study, 1 and 2 wt.% of aluminum were successfully incorporated into magnesium based AZ31 alloy to develop new AZ41 and AZ51 alloys using the technique of disintegrated melt deposition. AZ41–Al2O3 and AZ51–Al2O3 nanocomposites were also successfully synthesized through the simultaneous addition of aluminum (1 and 2 wt.%, respectively) and 1.5 vol.% nano-sized alumina into AZ31 magnesium following same route. Alloy and composite samples were then subsequently hot extruded at 400 °C and characterized. Microstructural characterization studies revealed equiaxed grain structure, reasonably uniform distribution of particulate and intermetallics in the matrix and minimal porosity. Physical properties characterization revealed that addition of both aluminum and nano-sized alumina reduced the coefficient of thermal expansion of monolithic AZ31. The presence of both Al and nano-sized Al2O3 particles also assisted in improving overall mechanical properties including microhardness, engineering and specific tensile strengths, ductility and work of fracture. The results suggest that these alloys and nanocomposites have significant potential in diverse engineering applications when compared to magnesium AZ31 alloy
Md Ershadul Alam, Samson Han, Quy Bau Nguyen, Abdel Magid Salem Hamouda, Manoj Gupta, Journal of Alloys and Compounds 509 (2011) 8522– 8529

L0152 – Enhancing Physical and Mechanical Properties of Mg Using Nanosized Al2O3 Particulates as Reinforcement

A magnesium-based composite with 1.1 volume percentage of nanosized Al2O3 particulates reinforcement was fabricated using an innovative disintegrated melt deposition technique followed by hot extrusion. Al2O3 particulates with an equivalent size of 50 nm were used as reinforcement. Microstructural characterization of the materials revealed grain refinement of magnesium matrix due to incorporation, retention, and uniform distribution of reinforcement. Physical properties characterization revealed that the addition of nano-Al2O3 particulates as reinforcement improves the dimensional stability of pure magnesium. Mechanical properties characterization revealed that the presence of nanoAl2O3 particulates as reinforcement leads to a significant increase in microhardness, dynamic elastic modulus, 0.2 pct yield strength (YS), ultimate tensile strength (UTS), and ductility of pure magnesium. The results revealed that the combined tensile properties of these materials are superior when compared to Mg reinforced with much higher volume percentage of SiC. An attempt is made in the present study to correlate the effect of nano-Al2O3 particulates as reinforcement with the microstructural, physical, and mechanical properties of magnesium.
S.F. Hassan, M. Gupta, Metallurgical and Materials Transactions A, Volume 36A, August 2005—2253

L0138 – Thermal Properties of Maleated Polyethylene/Layered Silicate Nanocomposites

Nanocomposites are a new class of composites in which the reinforcing phase dimensions are on the order of nanometer scale. In particular, the layered silicates are considered to be good candidates for the preparation of polymerinorganic nanocomposites. The mechanical and thermal properties of polymer can be altered by adding a few vol% of the nano-particles. The effect of the nano-sized particles on thermophysical properties such as melting and crystallization, coefficient of thermal expansion, and thermal conductivity was studied. After preparing the PEMA/layered silicate nanocomposites, the thermophysical properties were investigated by the differential scanning calorimetry and 3? methods. The content of layered silicate was varied from 0.5 to 5 vol%.
S. H. Lee, J. E. Kim, H. H. Song, S. W. Kim, International Journal of Thermophysics, Vol. 25, No. 5, September 2004

L0136 – Zirconia-MWCNT nanocomposites for biomedical applications obtained by colloidal processing

Zirconia ceramics are widely used as femoral heads, but case studies show that delayed failure can occur in vivo due to crack propagation. The addition of carbon nanotubes (CNT) is aimed to avoid the slow crack propagation and to enhance the toughness of the ceramic material used for prostheses. However, to really enhance the mechanical properties of the material it is necessary to achieve a uniform distribution of the CNT in the zirconia matrix. Colloidal processing has demonstrated to be suitable for obtaining ceramic-based composites with homogeneous distribution of the phases and high green density.This work compares the colloidal behavior of the as-received multi wall carbon nanotubes (ar-MWCNT) and the partially coated MWCNT (pc-MWCNT) when immersed in a nanozirconia matrix. With pc-MWCNT an improvement in the dispersion is proved. Moreover, the sintered samples that contain pc-MWCNT show higher density, lower grain size, improved toughness and enhanced hardness under the same sintering cycle when compared to the samples with ar-MWCNT.
N. Garmendia, I. Santacruz, R. Moreno, I. Obieta, J Mater Sci: Mater Med (2010) 21, 1445–1451

E0327 – Nanosized pure and Cr doped Al2 xScx(WO4)3 solid solutions

Nanosized solid solutions of the formula Al2?x?yScxCry(WO4)3, where x varies from 0 to 2 and y from 0.02 to 0.1 are synthesized for the first time by the co-precipitation method. X-ray powder diffraction, DTA/TG and TEM analyses demonstrate that the powders are pure solid solution compounds with orthorhombic structure, space group Pnca. Particle sizes between 10 and 70 nm are obtained after thermal treatment of the precipitates at 550 °C for 1 h for all compositions except in the case of Sc1.9Cr0.1(WO4)3. For the last one mean particle size of 64 nm was obtained after thermal treatment at 500 °C. The influence of the concentrations of Sc and Cr as well as of the temperature and duration of the thermal treatment on the particle size and size distribution are established and discussed.
A. Yordanova, I. Koseva, N. Velichkova, D. Kovacheva, D. Rabadjieva, V. Nikolov, Materials Research Bulletin 47 (2012) 1544–1549

E0295 – Phase equilibria in the system NaAl(WO4)2–NaCr(WO4)2

The phase equilibria in the system NaAl(WO4)2–NaCr(WO4)2 are investigated. Nanopowders are synthesized in the whole concentration region from NaAl(WO4)2 to NaCr(WO4)2 by a co-precipitation method. Using X-ray, DTA, TEM and SEM analyses, three concentration regions in the system are established: single-phase region of NaAl1??Cr?(WO4)2 solid solutions (x is between 0 and 0.08), with monoclinic structure, space group C2/c; single-phase region of NaAl1??Cr?(WO4)2 solid solutions (x is between 0.40 and 1.0) with monoclinic structure, space group P2/c; and two-phase region, where the above mentioned phases crystallize simultaneously (x is between 0.08 and 0.40). The thermal behaviour of the two pure boundary phases, as well as the influence of chromium on the thermal stability and the structural characteristics of the solid solutions are discussed.
I. Koseva, A. Yordanova, D. Rabadjieva, P. Tzvetkov, V. Nikolov, Materials Research Bulletin 47 (2012) 3580–3585

E0294 – Nanosized pure and Cr doped Al2?xInx(WO4)3 solid solutions

For a first time are synthesized nanosized solid solutions with formula Al2?xInxCry(WO4)2 (x = 0–2, y = 0.02–0.1). Co-precipitation method is used for the synthesis. It is established that only by strict maintenance of pH between 2.7 and 2.9 a pure, monophase product of In2(WO4)3 can be obtained. By X-ray powder diffraction and DTA/TG analyses, it is established that at room temperature the solid solutions Al2?xInx(WO4)2 at x value between 0 and 1.1 are orthorhombic and for x value between 1.1 and 2.0 are monoclinic. The phase transition temperatures are defined for different x values. Results from X-ray and TEM analyses show that nanosized pure Al2?xInx(WO4)2 and Cr-doped Al2?xInxCry(WO4)2 with size dimension between 10 and 40 nm can be successfully synthesized by co-precipitation method with subsequent thermal treatment at relatively low temperature (550 °C) for 1 h.
I. Koseva, A. Yordanova, P. Tzvetkov, V. Nikolov, D. Nihtianova, Materials Chemistry and Physics 132 (2012) 808– 814

E0233 – Structure and Magnetic Properties of Nickel–Zinc Ferrite Nanoparticles Prepared by Glass Crystallization Method

The magnetic and microstructure properties of Fe2O3–0.4NiO–0.6ZnO–B2O3 glass system, which was subjected to heat treatment in order to induce a magnetic crystalline phase (Ni0.4Zn0.6-Fe2O4 crystals) within the glass matrix, were investigated. DSC measurement was performed to reveal the crystallization temperature of the prepared glass sample. The obtained samples, produced by heat treatment at 765 C for various times (1, 1.5, 2, and 3 h), were characterized by X-ray diffraction, IR spectra, transmission electron microscopy, and vibrating sample magnetometer. The results indicated the formation of spinel Ni–Zn ferrite in the glass matrix. Particles of the ferrite with sizes ranging from 28 to 120nm depending on the sintering time were observed. The coercivity values for different heat-treatment samples were found to be in the range from 15.2 to 100 Oe. The combination of zinc content and sintering times leads to samples with saturation magnetization ranging from 12.25 to 17.82emu=g.
Ahmed M. El-Sayed, Esmat M. A. Hamzawy, Monatshefte f€ur Chemie 137, 1119–1125 (2006)

E0154 – An investigation into fire protection and water resistance of intumescent nano-coatings

The objective of the paper is to develop nano-coatings that can provide good fire protection for the underlying substrate. The thermal degradation and fire resistance of nano-coatings have been investigated by differential thermal analysis (DTA), thermogravimetry (TG) and fire performance test. It is illustrated that nano-coatings can give an excellent fire resistance. The dispersion state and bonding of nano-SiO2 particles are characterized by the use of transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). Water immersion test, fire performance test and mechanical test reveal that sodium silicate coating is vulnerable to water and hence fire resistance is severely damaged by water immersion, whereas nano-coatings demonstrate good water resistance and fire resistance even after water immersion.
Z. Wang, E. Han, W. Ke, Surface & Coatings Technology 201 (2006) 1528-1535

B3249 – Anatase phase formation kinetics in Ti and TiOx nanoparticles produced by gas-phase condensation

Anatase TiO2 nanoparticles were successfully synthesized by post-heat treatments of partially crystalline Ti and amorphous TiOx nanoparticles, respectively produced by inert gas condensation and subsequent oxidation. The nanoparticles condensed on a liquid-nitrogen containing cooling finger (sample LN) were identified to be partially crystalline Ti phase with ~ 10–20 vol.% amorphous TiOx. On the other hand, those condensed on a room-temperature cooling finger (sample RT) were almost completely amorphous TiOx phase. Differential scanning calorimetry scan curves of as-oxidized samples were interpreted using Kissinger analysis, the non-isothermal kinetics, and activation energy for the anatase formation was determined as ~ 455 and 865 kJ/mol for samples LN and RT, respectively. As-oxidized samples LN and RT were heat treated at 400 °C for 2 h, respectively (samples LN-H and RT-H). Samples LN-H and RT-H showed the onset of UV–visible light absorption near 400 nm and the optical band gap of 3.12 and 3.21 eV, respectively, corresponding to anatase. The sample LN-H showed faster photocatalytic decomposition of methylene blue and rhodamine B dyes compared to the sample RT-H due to high crystallinity of anatase and rutile phases.
Yun-Mo Sung, Jun-Su Park, Tae Geun Kim, Journal of Non-Crystalline Solids 358 (2012) 182–187

B3174 – Effect of 1 wt% LiF additive on the densification of nanocrystalline Y2O3 ceramics by spark plasma sintering

Densification of nanocrystalline cubic yttria (nc-Y2O3) powder, with 18 nm crystal size and 1 wt% LiF as a sintering additive was investigated. Specimens were fabricated by spark plasma sintering at 100 MPa, within the temperature range of 700–1500 °C. Sintering at 700 °C for 5 and 20 min resulted in 95% and 99.7% dense specimens, with an average grain size of 84 and 130 nm, respectively. nc-Y2O3 without additive was only 65% dense at 700 °C for 5 min. The presence of LiF at low sintering temperatures facilitated rapid densification by particle sliding and jamming release. Sintering at high temperatures resulted in segregation of LiF to the grain boundaries and its entrapment as globular phase within the fast growing Y2O3 grains. The sintering enhancement advantage of LiF was lost at high SPS temperatures.
Rachel Marder, Rachman Chaim, Geoffroy Chevallier, Claude Estournès, Journal of the European Ceramic Society 31 (2011) 1057–1066

B3173 – Densification and polymorphic transition of multiphase Y2O3 nanoparticles during spark plasma sintering

Multiphase (MP) monoclinic and cubic Y2O3 nanoparticles, 40 nm in diameter, were densified by spark plasma sintering for 5–15 min and100 MPa at 1000 °C, 1100 °C, and 1500 °C. Densification started with pressure increase at room temperature. Densification stagnated during heating compared to the high shrinkage rate in cubic single-phase reference nanopowder. The limited densification of the MP nanopowder originated from the vermicular structure (skeleton) formed during the heating. Interface controlled monoclinic to cubic polymorphic transformation above 980 °C led to the formation of large spherical cubic grains within the vermicular matrix. This resulted in the loss of the nanocrystalline character and low final density.
R. Marder, R. Chaim, G. Chevallier, C. Estournes, Materials Science and Engineering A 528 (2011) 7200– 7206

B3135 – Nanosized copper ferrite materials:Mechanochemical synthesis and characterization

Nanodimensional powders of cubic copper ferrite are synthesized by two-steps procedure of co-precipitation of copper and iron hydroxide carbonates, followed by mechanochemical treatment. X-ray powder diffraction, Mössbauer spectroscopy and temperature-programmed reduction are used for the characterization of the obtained materials. Their catalytic behavior is tested in methanol decomposition to hydrogen and CO and total oxidation of toluene. Formation of nanosized ferrite material is registered even after one hour of milling time. It is established that the prolonging of treatment procedure decreases the dispersion of the obtained product with the appearance of Fe2O3. It is demonstrated that the catalytic behavior of the samples depends not only on their initial phase composition, but on the concomitant ferrite phase transformations by the influence of the reaction medium.
Elina Manova, Tanya Tsoncheva, Daniela Paneva, Margarita Popova, Nikolay Velinov, Boris Kunev, Krassimir Tenchev, Ivan Mitov, Journal of Solid State Chemistry 184 (2011) 1153–1158

B3128 – More on the reactivity of olivine LiFePO4 nano-particles with atmosphere at moderate temperature

The changes appearing for LiFePO4-C nano-composites exposed to atmosphere at 12°C have been structurally and chemically examined by the use of TGA, XRD, XPS, Mössbauer, 7Li MAS NMR and electrochemical methods. The results conclude that a highly disordered phase resulting from the aging of LiFePO4 appears on the surface of the grains of the material, is assigned to a phosphate phase and can insert lithium around 2.6V with poor reversibility. The essential role of water has been investigated and clearly demonstrated. Thus, the aging mechanism occurring in hot humid air is completely different from a simple oxidation as well as
Jean-Frédéric Martin, Marine Cuisinier, Nicolas Dupré, Atsuo Yamada, Ryoji Kanno, Dominique Guyomard, Journal of Power Sources 196 (2011) 2155–2163

B3125 – Nanocrystalline Ti2/3Sn1/3O2 as anode material for Li-ion batteries

We prepared nanocrystalline Ti2/3Sn1/3O2 by a coprecipitation method starting from Ti(isopropoxide)4 and SnCl4·5H2O followed by calcination at 600 °C. TEM and XRD measurements reveal crystallite sizes of about 5 nm and a crystal structure equivalent to those of TiO2 rutile and SnO2 cassiterite. The local structure was investigated with 119Sn NMR and Sn Mössbauer spectroscopy. The material was cycled with C/20 at voltages between 3.0 and 0.02 V against Li metal. Specific capacities of 300 mAh g?1 were obtained for 100 cycles with voltage profiles very similar to those of pure SnO2. Faster cycling leads to strong decrease of the capacities but after returning to C/20 the initial values are obtained.
Ibrahim Issac, Marco Scheuermann, Sebastian M. Becker, Elisa Gil Bardají, Christel Adelhelm, Di Wang, Christian Kübel, Sylvio Indris, Journal of Power Sources 196 (2011) 9689– 9695

B3078 – Formation of Graphene Oxide Nanocomposites from Carbon Dioxide Using Ammonia Borane

To efficiently recycle CO(2) to economically viable products such as liquid fuels and carbon nanomaterials, the reactivity of CO(2) is required to be fully understood. We have investigated the reaction of CO(2) with ammonia borane (AB), both molecules being able to function as either an acid or a base, to obtain more insights into the amphoteric activity of CO(2). In the present work, we demonstrate that CO(2) can be converted to graphene oxide (GO) using AB at moderate conditions. The conversion consists of two consecutive steps: CO(2) fixation (CO(2) pressure < 3 MPa and temperature < 100 °C) and graphenization (600-750 °C under 0.1 MPa of N(2)). The first step generates a solid compound that contains methoxy (OCH(3)), formate (HCOO) and aliphatic groups while the second graphenization is the pyrolysis of the solid compound to produce graphene oxide-boron oxide nanocomposites, which have been confirmed by micro-Raman spectroscopy, solid state (13)C and (11)B magic angle spinning-nuclear magnetic resonance (MAS-NMR), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Our observations also show that the mass of solid product in CO(2) fixation process and raw graphene oxide nanocomposites is twice and 1.2 times that of AB initially charged, respectively. The formation of aliphatic groups without using metal-containing compounds at mild conditions is of great interest to the synthesis of various organic products starting from CO(2.).
Junshe Zhang, Yu Zhao, Xudong Guan, Ruth E. Stark, Daniel L. Akins, Jae W Lee, J Phys Chem C Nanomater Interfaces. 2012 January 17; 116(3) 2639–2644

B3051 – Effect of sintering in ball-milled K2Bi8Se13 thermoelectric nano-composites

K2Bi8Se13 has many attractive features for thermoelectric applications. Recently, K2Bi8Se13-based nanocomposite materials, consisting of nano-crystalline, micro-crystalline and amorphous phases, have been fabricated based on powder technology techniques. The Seebeck coefficient has been enhanced while the thermal conductivity has been decreased presenting, thus, interesting behavior. The behavior of the materials under heat treatment conditions is now of interest, as the application of sintering process is necessary for the development of thermoelectric modules. In this work, the crystallization of the K2Bi8Se13-based nano-composites is studied using Differential Scanning Calorimetry. The results show that crystallization follows a multiple-step process with different activation energies. The thermoelectric properties are also discussed in the range that crystallization occurs
E. Hatzikraniotis, M.Ioannou, K.Chrissafis, D.Y.Chung, K.M.Paraskevopoulos, Th.Kyratsi, Journal of Solid State Chemistry 193 (2012) 137–141

B3013 – Energetics of single-wall carbon nanotubes as revealed by calorimetry and neutron scattering

Bundles of (10,10) single-wall carbon nanotubes (SWCNTs) have been studied by high-temperature oxidation calorimetry and inelastic neutron scattering to obtain standard formation enthalpies and entropies at 298 K. SWCNTs are found to be only moderately less stable than graphite, and are significantly more stable than their fullerene counterparts. They are 7 kJ mol 1 metastable in terms of enthalpy relative to graphite, and just 5 kJ mol 1 less stable than diamond. Despite striking differences in vibrational dynamics of carbon atoms in SWCNTs and graphite, their thermodynamic properties at room and higher temperatures are dominated by the same set of high energy vibrations, reflected in very similar vibrational entropies. However, the energetics of SWCNTs are governed by the diameter-dependent enthalpic contributions, but not the specifics of phonon density of states.
Andrey A. Levchenko, Alexander I. Kolesnikov, Olga Trofymluk, Alexandra Navrotsky, Carbon 49 (2011) 949-954

B3011 – Stability of poly(L-lactide)/TiO2 nanocomposite thin films under UV irradiation at 254 nm

Poly(L-lactide)/titania (PLLA/TiO2) nanocomposites were in situ synthesized through ring-opening polymerization of L-lactide. Two types of TiO2, anatase and rutile, were used in the synthesis of composites. The chemical structure, crystallinity, thermal stability and morphology of composite thin films were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of TiO2 on the stability of the nanocomposites under UV irradiation as a function of time were investigated by FTIR, XRD, UV absorption spectroscopy and differential scanning calorimetry (DSC). The obtained results indicated that rutile TiO2 particles have a screening effect while anatase TiO2 acts as a photocatalyst. The DSC results revealed that anatase TiO2 embedded in bulk of the films produces the same effect as rutile TiO2.
Wei-Wei Wang, Chang-Zhen Man, Chun-Mei Zhang, Long Jiang, Yi Dan, Thien-Phap Nguyen, Stability of poly(L-lactide)/TiO2 nanocomposite thin films under UV irradiation at 254 nm

B3010 – Morphology and properties of UV/ozone treated graphite nanoplatelet/epoxy nanocomposites

The nanoscopic morphologies, thermo-mechanical, mechanical and electrical properties of graphite nanoplatelet (GNP)/epoxy nanocomposites were evaluated after UV/O3 treatment of graphite. Composites containing uniformly distributed GNP reinforcements of well controlled exfoliation were prepared through the graphite intercalation compound technique, graphite surface treatment and optimized ultrasonication process with the aid of solvent. The UV/O3 treatment showed ameliorating effects on various properties of nanocomposites arising from the enhanced graphite-epoxy interfacial adhesion. The flexural moduli and strengths were higher after treatment for a given GNP content. The thermo-mechanical properties, such as glass transition temperature and storage modulus, increased with increasing exposure duration before saturation after about 30 min of exposure. The electrical resistivity of treated nanocomposites decreased with increasing GNP content much faster than those containing untreated GNPs. The percolation thresholds of both nanocomposites with and without UV/O3 treatment were similarly about 1 wt%, which is much lower than the values reported in the literature. The interparticle distances were predicted for different particle aspect ratios and volume fractions, and the comparison between the prediction and the experimental aspect ratio for a given percolation threshold indicates reasonable agreement.
Jing Li, Man Lung Sham, Jang-Kyo Kim, Gad Marom, Composites Science and Technology 67 (2007) 296–305

B2981 – Thermal conductivity and specific heat capacity measurements of Al2O3 nanofluids

Thermal conductivities and specific heat capacities of nanoparticles of Al2O3 dispersed in water and ethylene glycol as a function of the particle volume fraction and at temperatures between 298 and 338 K were measured. The steady-state coaxial cylinders method, using a C80D microcalorimeter (Setaram, France) equipped with special calorimetric vessels, was used for the thermal conductivities measurements. The heat capacities were measured with a Micro DSC II microcalorimeter (Setaram, France) with batch cells designed in our laboratory and the ‘‘scanning or continuous method.’’ The Hamilton–Crosser model properly accounts for the thermal conductivity of the studied nanofluids. Assuming that the nanoparticles and the base fluid are in thermal equilibrium, the experimental specific heat capacities of nanofluids are correctly justified.
Benigno Barbes, Ricardo Paramo, Eduardo Blanco, Mar?a Jose Pastoriza-Gallego, Manuel M. Pineiro, Jose Luis Legido, Carlos Casanova, J Therm Anal Calorim, 2012

B2919 – Effect of different nanoparticles on HDPE UV stability

In the present study different series of HDPE nanocomposites were prepared by melt mixing on a Haake-Buchler Reomixer, containing 2.5 wt% of multiwall carbon nanotubes, pristine and modified montmorillonite, and SiO2 nanoparticles. Nanocomposites in the formof thin films were exposed to UV irradiation at 280 nm at constant temperature (25 C) and constant relative humidity (50%) for several times. From tensile strength and Young’s Modulus measurements it was verified a high increase with initial UV irradiation times (till 100 h) and a slight reduction thereafter. The increase was higher in nanocomposites compared with neat HDPE, except these containing MWCNTs, and was attributed to the crystallinity increase in the particular samples. The mechanical properties reduction at higher UV irradiation times was attributed to the extensive macromolecular chain scission causing irregularities and holes in film surfaces. However, from FTIR study itwas found that SiO2 and organically modified montmorillonite cause a serious effect on HDPE during UV degradation. Newchemical compounds containing carbonyl, vinyl and hydroxyl groups were formed. It seems that these nanoparticles have an accelerating effect acting as catalysts to HDPE photo-oxidation. This was also verified from micro-Raman analysis. Untreated montmorillonite has also a small influencing effect while neat HDPE and nanocomposites containing multiwall carbon nanotubes have the highest UV stability
I. Grigoriadou, K.M. Paraskevopoulos, K. Chrissafis, E. Pavlidou, T.-G. Stamkopoulos, D. Bikiaris, Polymer Degradation and Stability 96 (2011) 151e163

B2757 – An immersion calorimetry study of the interaction of organic compounds with carbon nanotube surfaces

The interaction of organic chemicals with the surface of carbon nanotubes (CNTs) has been studied by immersion calorimetry revealing new information about the unique CNT surface structures. The curvature of the graphene sheets of in the CNTs increases the adsorption strength of aromatic compounds compared to flat graphite surfaces. For a given CNT, the adsorption affinity of a non-polar aromatic molecule correlated poorly with the CNT hydrophobicity. Comparison of the immersion enthalpies that evolved when the solids were immersed in organic chemicals reveals the formation of p–p stacking interactions, H-bonds or electron–accepting interactions depending on the CNT surfaces and on the immersion substrate. The number of oxygen groups on CNTs seems to modify the electron density of their surfaces and therefore the interaction mechanism with the adsorbates.
E. Castillejos, B. Bachiller-Baeza, I. Rodr?guez-Ramos, A. Guerrero-Ruiz, Carbon 50 (2012) 2731-2740

B1986 – Preparation and characterization of AgI nanoparticles with controlled size, morphology and crystal structure

AgI nanoparticles were prepared by solution-based routes using water-soluble anionic or cationic polyelectrolytes as capping agents. Depending on the polyelectrolytes, AgI nanoparticles with well-defined morphology, size, and phase compositions were obtained: the use of poly (sodium 4-styrenesulfonate) (PSS) resulted in AgI nano-rods of beta-AgI in wurtzite structure (2H); with poly(acrylic acid sodium salt) (PAS) truncated-tetrahedron shaped gamma-AgI nanoparticles (nanotetrahedra) in zinc-blende structure (3C) were obtained; by employing poly (diallyldimethylammonium chloride) (PDADMAC) plate-like AgI nanoparticles (nano-plates) consisting of unusual polytype phases of AgI (7H and 9R) were formed. Macroscopically unstable gamma-AgI and 7H and 9R phases could be stabilized in the form of nanocrystalline powders. They transform reversibly into the high temperature alpha-AgI phase and exhibit unusually high ionic conductivity and substantially smaller transformation enthalpy values compared to the macroscopic beta-AgI.
Y-G. Guo, J-S. Lee, J. Maier, Solid State Ionics 177 (2006) 2467-2471

A2348 – Influence of annealing temperature and doping rate on the magnetic properties of Zr–Mn substituted Sr-hexaferrite nanoparticles

A series of M-type strontium hexaferrite samples having nominal composition SrZrxMnxFe12?2xO19 (where x = 0.0–0.8) has been synthesized by the co-precipitation method. All the samples synthesized were of single magnetoplumbite phase. The particle size was found to be in the 40–65 nm range for the samples annealed at 1193 K while the samples annealed at 1443 K were in the 100–200 nm range. The saturation magnetization increase with temperature and reached maxima for the samples annealed at 1393 K and then start to decrease while the coercivity decreases regularly with temperature. The decrease in coercivity is due to the increase in the particle size of the sample with temperature. The saturation magnetization increase for the samples doped with Zr–Mn up to x = 0.4 doping rate and higher substitution lead to decrease in saturation magnetization. The coercivity decrease with the increase in Zr–Mn substitution. The behavior of saturation magnetization has been explained on the basis of occupation of the substituted cations at different iron sites. The increase in saturation magnetization and decrease in coercivity suggest that the synthesized materials can be used for the application of recording media.
Muhammad Javed Iqbal, Muhammad Naeem Ashiq, Pablo Hernández-Gómez, José María Munoz Munoz, Carlos Torres Cabrera, Journal of Alloys and Compounds 500 (2010) 113–116

A2313 – Mechanism of hydrothermal growth of ferroelectric PZT nanowires

The formation mechanism of hydrothermally grown monocrystalline ferroelectric PZT nanowires is investigated. It is shown that the growth proceeds via a two-step process. Particles of the centrosymmetric PX-phase grow initially, having a fibrous morphology which is compatible with the highly anisotropic crystalline structure of this material. In the second stage, the PX-phase transforms into the ferroelectric perovskite phase, retaining the initial fibrous morphology. The solubility limit of Zr ions in the PX phase is maintained into the perovskite phase. While the PX and the perovskite phases have a similar composition, the reconstructive transformation process, in which edge-sharing octahedra chains of the PX-phase transform into a 3D network of corner sharing octahedra in the perovskite, involves incorporation and then release of oxygen (or hydroxyl).
Jin Wang, Alexandre Durussel, Cosmin Silviu Sandu, Mtabazi Geofrey Sahini, Zhangbing He, Nava Setter, Journal ofCrystalGrowth347(2012)1–6

A2312 – Reaction characteristics of Al/Fe2O3 nanocomposites

Al/Fe2O3 nonacomposites have explosive and high exothermic properties by thermite reaction. In this study, Al/Fe2O3 xerogel nanocomposites were prepared by sol–gel method and thermite reaction performance was compared with those prepared by physical mixing with sonication. Scanning electron microscopy (SEM) images of Al/Fe2O3 xerogel nanocomposites show that network structure of Fe2O3 gel covers Al nanoparticles efficiently and this indicates that improvement of thermite reaction performance due to close contact between a fuel and an oxidizer. Optimum mole ratio of Al/Fe was determined to be 2 by thermite reaction performance by differential scanning calorimetry (DSC) analysis. At Al/Fe ratio of 2, thermite reaction enthalpy of the Al/Fe2O3 xerogel nancomposite was 991.4 J/g, which was higher by a factor of four than that of the nanocomposite prepared by physical mixing.
Moon-Soo Shin, Jae-Kyeong Kim, Jun-Woo Kim, Carlos Alberto Mendes Moraes, Hyoun-Soo Kim, Kee-Kahb Koo, Journal of Industrial and Engineering Chemistry 18 (2012) 1768–1773

A2297 – Effective photocatalytic decolorization of methyl orange utilizing TiO2/ZnO/chitosan nanocomposite films under simulated solar irradiation

Titanium dioxide/zinc oxide/chitosan nanocomposite thin films (TiO2/ZnO/chitosan NTFs) were prepared by entrapping zinc ions and nanosized TiO2 in chitosan thin films under mild conditions. The structure, thermal property, and surface morphology of TiO2/ZnO/chitosan NTFs were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity of TiO2/ZnO/chitosan NTFs was evaluated by photocatalytic decolorization of methyl orange in aqueous solution as a model pollutant under simulated solar irradiation. The HRTEM results revealed that well-dispersed and uniform TiO2/ZnO nanocomposite with diameters of 5–15 nm were embedded in chitosan films. The TiO2/ZnO/chitosan NTFs exhibited high photocatalytic activity under simulated solar irradiation. After 4 h of irradiation by simulated solar light, over 97% of methyl orange solution (15 mg L? 1) was decolorized with 0.5 g L? 1 of the photocatalyst. The TiO2/ZnO/chitosan NTFs could be reused, which meant that the adsorption-photocatalytic decolorization process could be operated at a relatively low cost. Since this process does not require the addition of hydrogen peroxide and uses solar light, it can be developed as an economically feasible and environmentally friendly method to decolorize or treat dye wastewater using sunlight.
Huayue Zhu, Ru Jiang, Yongqian Fu, Yujiang Guan, Jun Yao, Ling Xiao, Guangming Zeng, Desalination 286 (2012) 41–48

A2266 – Improved capacitive properties of layered manganese dioxide grown as nanowires

Birnesite-type MnO2 nanowires were prepared by direct reaction of NaMnO4 with ethanol under hydrothermal conditions. Changing the pressure vessel load allowed a layered oxide in the form of nanoflakes to be obtained. The resulting nanowires were 10–20 nm wide and several micrometers long. Interestingly, the nanowires were poorly crystalline as revealed by their XRD patterns; also, they exhibited especially strong (1 0 0) reflections that were assigned to 1D growth of the particles. By contrast, the XRD pattern for the nanoflakes was consistent with an increased crystallinity as a result of 2D particle growth. The electrochemical properties of the nanowires and nanoflakes in 0.5 M Na2SO4 were evaluated by cyclic voltammetry and galvanostatic charge/discharge testing in two- and three-electrode cells. The nanowires exhibited an ideal capacitive behavior and a higher specific capacitance than the nanoflakes (191 vs. 157 F g?1). In our opinion, the improved performance of the nanowires is a result of their high structural disorder and lattice strain rather than their higher specific surface area.
O.A. Vargas, A. Caballero, L. Hernán, J. Morales, Journal of Power Sources 196 (2011) 3350–3354

A2264 – Dissolution and alkylation of industrially produced multi-walled carbon nanotubes

Industrial, CVD multi-walled carbon nanotubes are shown to form true solutions by reduction with alkali metals and subsequent exposure to polar solvents such as DMSO. Addition of an electrophile such as bromo-decanoic acid allows functionalization of the tubes. The whole process, dissolution and functionalization includes no harsh treatment such as acid treatment and/or sonication and allows to saturate the outer surface of the MWCNTs with functional groups. Comparison is made with previous work on single-walled carbon nanotubes.
Damien Voiry, Cristina Valles, Olivier Roubeau, Alain Pénicaud, Carbon 49 (2011) 170-175

A2263 – Novel lithium titanate hydrate nanotubes with outstanding rate capabilities and long cycle life

Novel lithium titanate hydrate nanotubes for lithium ion batteries have been easily prepared via a hydrothermal method. This material demonstrates high energy density, outstanding rate capabilities and a very long cycle life comparable to those of supercapacitors. At a rate equivalent to a 10-min total charge/discharge, the as-prepared lithium titanate hydrate nanotubes exhibit a life of over 5000 charge/discharge cycles while still retaining up to 86.3% of its original capacity. The abilities of lithium titanate hydrate nanotubes to fully charge within minutes for thousands of times and still retain a large capacity may find promising applications in hybrid and plug-in hybrid electric vehicles.
Rui Xu, Junrong Li, Ao Tan, Zilong Tang, Zhongtai Zhang, Journal of Power Sources 196 (2011) 2283–2288

A2261 – Multifunctional poly(aspartic acid) nanoparticles containing iron oxide nanocrystals and doxorubicin for simultaneous cancer diagnosis and therapy

Multifunctional poly(aspartic acid) nanoparticles for simultaneous cancer diagnosis and therapy were developed. First, iron oxide nanocrystals were loaded in poly(aspartic acid) nanoparticles through an emulsion method using octadecyl grafted poly(aspartic acid). The influence of the organic solvent, used to disperse the hydrophobic iron oxide nanocrystals, on the size and loading efficiency of iron oxide nanocrystals loaded poly(aspartic acid) nanoparticles was investigated. Next, an anticancer drug, doxorubicin (DOX), was incorporated in the magnetic poly(aspartic acid) nanoparticles (MPAN). The presence of iron oxide nanocrystals in the poly(aspartic acid) nanoparticles and their size distribution were confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and dynamic light scattering (DLS), respectively. The drug release behavior was also observed for 3 days. From the results of T2 weighted MR imaging and MTT assays, the DOX loaded MPAN showed high T2 relaxivity coefficients and high cytotoxicity for cancer cells
Hee-Man Yang, Byung Chang Oh, Jong Hun Kim, Taebin Ahn, Ho-Seong Nam, Chan Woo Park, Jong-Duk Kim, Colloids and Surfaces A: Physicochem. Eng. Aspects 391 (2011) 208– 215

A2257 – Synthesis of TiO2 nano-powders prepared from purified sulphate leach liquor of red mud

The research work presented in this paper is focused on the development of a purification process of red mud sulphate leach liquor for the recovery of titanium oxide (TiO2) nano-powders in the form of anatase. Initially, titanium was extracted over iron and aluminium from the leach liquor by solvent extraction using Cyanex 272 in toluene, at pH: 0.3 and T: 25 °C, with 40% extractant concentration. Stripping of the loaded, with titanium, organic phase was carried out by diluted HCl (3 mol/L) at ambient temperature. Finally, the recovery of titanium nano-powder, in the form of anatase, was performed by chemical precipitation at pH: 6 and T: 95 °C, using 10 wt% MgO pulp as neutralizing agent. The produced precipitates were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric/differential thermal analysis (TGA/DTA). Their morphological characteristics and microstructure were studied by scanning electron microscopy (SEM). High grade titanium white precipitate, in the form of anatase, was obtained. Iron concentration in the precipitate did not exceed 0.3%, whereas no aluminium was detected.
P.E. Tsakiridis, P. Oustadakis, A. Katsiapi, M. Perraki, S. Agatzini-Leonardou, Journal of Hazardous Materials 194 (2011) 42–47

A2256 – Rapidly synthesis of nanocrystalline MgIn2O4 spinel using combustion and solid state chemistry

Nanometric/submicronic powders of magnesium indate spinel MgIn2O4 were prepared with a two-steps process. First, nano-oxides of In2O3 and MgO were obtained by combustion of aqueous solutions of metal nitrates (as an oxidizer) and different fuels (glycine/urea/citric acid). Then, the as-prepared combustion ashes were converted into pure spinels after calcinations at elevated temperature. The as-prepared powders spinels have nanometric or submicronic grain size. This process allows preparing the MgIn2O4 spinel compound in 1 day whilst 10 days were necessary when the classical solid state chemistry is used. In this paper, we compare these two ways and study the effect of different reaction parameters, such as the nature of fuels or the fuel/oxidiser ratio. Crystallites sizes of the synthesized compounds were investigated by powder X-ray diffraction and Scanning Electron Microscopy.
Suzy Surblé, Dominique Gosset, Mickaël Dollé, Gianguido Baldinozzi, Stéphane Urvoy, David Siméone, Solid State Sciences 13 (2011) 42e48

A2255 – Aerosol-assisted self-assembly of hybrid Layered Double Hydroxide particles into spherical architectures

Acetate intercalated NiAl-Layered Double Hydroxide nanoparticles were prepared by polyol process and further used as building blocks to form hybrid LDH spheres by a spray drying technique. The spherical aggregated LDH particles display a polydispersed size with a diameter ranging from 47 nm to 2 ?m. The analysis of the thermal behavior evidenced that the spherical form was maintained upon calcination up to 1100°C, giving rise to derived mixed oxide (NiO+NiAl(2)O(4)) nanospheres. Interestingly, the spherical morphology of the LDH materials was also retained during anion exchange process. The replacement of the intercalated acetate anion by of a voluminous anion such as dodecylsulfate induces an increase of the nanosphere mean diameter of 65%. The different materials were deeply characterized using X-ray diffraction, FTIR spectroscopy, scanning and transmission electron microscopies, dynamic light scattering, thermal analysis and nitrogen sorption.
Vanessa Prevot, Claire Szczepaniak, Maguy Jaber, Journal of Colloid and Interface Science 356 (2011) 566–572

A2254 – Chemical reactivity of self-organized alumina nanopores in aqueous medium

This work is devoted to the characterization of the structure and chemistry of small self-organized nanopores of aluminum oxide in aqueous medium (diameter <20 nm). A structural model based on AlO4/AlO6 clusters is proposed to describe the amorphous oxide constituting the walls of the nanostructure. X-ray absorption near edge spectroscopy measurements, electrokinetic measurements and O18 tracer experiments bring to light the structural changes and the specific diffusion mechanism in the nanometer network. Immersion in boiling water induces both the transformation of AlO4 to AlO6 clusters and the release of sulfate species by hydrolysis. Water molecules rapidly diffuse in the nanostructure, but ion diffusion is selective because of surface positive charges and overlap of the surface electric field in very small pores.
E. Rocca, D. Vantelon, A. Gehin, M. Augros, A. Viola, Acta Materialia 59 (2011) 962–970

A2251 – Characterization of Manganese-doped Willemite Green Phosphor Gel Powders

Nanocrystalline manganese-doped zinc silicate (Zn2?xMnxSiO4; x = 0-12.0 mol%) powder phosphors were prepared by the sol-gel process. Zinc chloride, tetraethylorthosilicate, and manganese chloride were employed as precursors. The influences of water concentration on the crystallization and photoluminescence of the phosphors were investigated. Single-phase wiemite (?-Zn2SiO4) started to crystallize after calcining at 600°C for powders derived from low-water-conen so, whie ?-Zn2SiO4 became the dominated phase with residual ZnO trace for high-water-content sol derived powders as calcining at below 900 °C. On firing at 800°–1200°C, the resulting phosphors had the average crystallite sizes of 15~38 nm. With various content of water and heating the powders at 800°C, the prepared phosphors exhibited yellow and green emission peaking at 556 and 524 nm, respectively. Upon heating at 1200 °C, powder phosphors exhibited prominent photoluminescence emission bands peaked at 522~526 nm, depending on the doping content. The luminous efficiency has been investigated as a function of dopant content and heating temperature.
Mu-Tsun Tsai , Yi-Hsun Lin, Jing-Ru Yang, IOP Conf.Series:MaterialsScienceandEngineering 18 (2011) 032026doi:

A2243 – Phase-transitions of ?- and ?-Bi2O3 nanowires

The transition temperatures for the ? or ? to ? and the ? to liquid phase for ?- and ?-Bi2O3 nanowires were investigated. We found that there is a size effect for the ? to liquid phase transition but not the ? or ? to ? phase transition. This is because the ? to liquid phase transition involves bond rupture as well as surface area reduction, whereas the ? or ? to ? is only solid–solid phase transition, which requires only the reorganization of the bonds. This is the first time the phase transitions of the Bi2O3 nanowires have been investigated and their size effect revealed.
Yongfu Qiu, Minlin Yang, Hongbo Fan, Yuanzhi Zuo, Youyuan Shao, Yongjun Xu, Xiaoxi Yang, Shihe Yang, Materials Letters 65 (2011) 780–782

A2240 – Preparation and band gap energies of ZnO nanotubes, nanorods and spherical nanostructures

Nanostructured zinc oxides were prepared with no catalysts or substrates used. The advantages of this method were a direct and a relatively easy way of getting large amounts of different morphologies of nanostructured ZnO. Another advantage was the formation of the nanotubes at a relatively lower temperature than most other methods. This presented a promising way for commercialization of the ZnO nanomaterials. The materials were characterized using simultaneous thermogravimetric analysis, X-Ray diffraction and transmission electron microscopy. Structures such as nanotubes, nanorods and spherically shaped crystals were formed at certain annealing temperatures. It was found that the ZnO nanotubes grew in the direction of the c-axis. For comparisons of size and morphology, the ZnO precursors were annealed at 300 °C, 400 °C and 700 °C. The lattice parameter of the ZnO nanotube was smaller than conventional micron sized materials. It was also found that the band gap energies of the ZnO nanomaterials were dependent on the morphology of the nanostructures.
Roshidah Rusdi, Azilah Abd Rahman, Nor Sabirin Mohamed, Norashikin Kamarudin, Norlida Kamarulzaman, Powder Technology 210 (2011) 18–22

A2239 – Synthesis of (Gd0.95Eu0.05)(OH)3 Nanomaterials and Their Transformation into Single Crystalline (Gd0.95Eu0.05)2O3 with Enhanced Photoluminescence properties

In this work, hexagonal solid solutions of (Gd0.95Eu0.05)(OH)3 with two distinctive morphologies of nanorods and nanotubes were successfully synthesized via hydrothermal treatment of mixed nitrate solutions in the presence of ammonium hydroxide. The hydroxide samples exhibited characteristic Eu3+ photoluminescence through the energy transfer from Gd3+ to Eu3+ and the self-excitation of Eu3+. The hydroxide precursors transformed into cubic (Gd0.95Eu0.05)2O3 at ~500 °C via an intermediate monoclinic (Gd0.95Eu0.05)OOH phase, and the Eu3+ coordination accordingly experienced symmetry changes from D3h to C2v, and then to C2/S6. The cubic (Gd0.95Eu0.05)2O3 well retained the original morphologies of their polycrystalline precursors and exhibited a single-crystalline character at 1000 °C . Greatly enhanced photoluminescence (~5000 times that of the hydroxides) was observed for the phase conversion.
Q. Zhu, J.-G. Li, X. D. Li, X. D. Sun, IOP Conf.Series:MaterialsScienceandEngineering 18 (2011) 102011

A2236 – Low degree of functionalization of Single-Walled Carbon Nanotubes probed by highly sensitive characterization techniques

Single-Walled Carbon Nanotubes (SWCNTs) were functionalized using a one-step radical addition procedure leading to a desired low functionalization degree. Based on well chosen techniques, the characterization of the functionalized samples allows having a good feedback on the functionalization process. We were able to determine the functionalization level and the nature of the bonds between the SWCNT surface and the functional groups. By means of a TGA–mass spectrometry coupling technique, the mechanisms of detachment upon heating were used to determine the nature of the grafted functional groups. In addition to the expected groups, unexpected groups were covalently grafted on the sample surface. Based on inert gas adsorption properties, we show that the functional groups are unambiguously grafted on the SWCNT sidewalls.
Johann Lejosne a, Guillaume Mercier a, Victor Mamane b, Yves Fort b, Jean-François Maréché, Edward McRae, Fabrice Valsaque, Brigitte Vigolo, Carbon 49 (2011) 3010-3018

A2231 – An anionic surfactant-templated synthesis and lamellar ordering of Co(OH)2 and Co3O4 nanodisks

Co(OH)2 nanodisks were synthesized using a surfactant lamellar mesophase as a soft template. From the Co(OH)2 nanodisks, porous Co3O4 nanodisks could also be obtained after a heat treatment. Co(OH)2 nanodisks were successfully converted to porous Co3O4 nanodisks via thermal oxidation. Using the Co3O4 nanodisks as a basic building block and sodium dodecyl sulfate as a structure-directing agent, the lamellar mesostructures could be formed. The lamellar ordering is expected to originate through cooperative interaction-induced self-assembly and evaporation-induced self-assembly.
Kwang-Suk Jang, Jong-Duk Kim, Materials Chemistry and Physics 125 (2011) 777–783

A2222 – Mg–Al Layered double hydroxide nanoparticles. Evaluation of the thermal stability in polypropylene matrix

Layered Double Hydroxide (LDH) particles intercalated with dodecylsulfate anions were prepared following different methods and analysed by thermogravimetry (TGA) and X-ray diffraction (XRD). Two commercial grades of MgAl LDH particles were used as LDH precursors. Two-step reconstitution was found to be the most effective route to prepare dodecylsulfate intercalated LDH particles. The obtained particles were melt blended with polypropylene at a 10 wt.% loading. The thermal stability and flame retardant behaviour of the resultant nanocomposites were studied with TGA and limiting oxygen index tests. The mechanical properties were also characterized. The experimental results reveal the potential of these organic modified LDH particles to improve both the thermal stability of polypropylene matrix and the mechanical properties.
M. Ardanuy, J.I. Velasco, Applied Clay Science 51 (2011) 341–347

A2214 – Correlation of compaction pressure, green density, pore size distribution and sintering temperature of a nano-crystalline 2Y-TZP-Al2O3 composite

Highly sinter-active nano crystalline composite powder of 2 mol% yttria doped tetragonal zirconia polycrystal (2Y-TZP) with 2 wt% alumina was synthesized by co-precipitation method. Crystallization temperature of the amorphous precursor powder, measured from simultaneous thermogravimetric (TG) and differential thermal analysis (DTA) techniques was found to be ?470 °C. The powder was calcined at different temperatures in the range of 700–1000 °C. XRD patterns of the calcined powders revealed the presence of a single tetragonal phase. Particle size of the calcined powder measured by different techniques (X-ray line broadening, BET surface area and laser scattering technique) indicated an increase in the average particle size with calcination temperature. The study of compaction behaviour revealed the presence of soft agglomerates in the calcined powder. Pore size distribution of the green compacts obtained from a mercury porosimeter was found to be monomodal above a critical pressure. The onset temperature of sintering was found to increase with calcination temperature. Powders calcined at 800 °C and 900 °C had shown better sinterability at 1200 °C owing to the presence of finer pores with a narrow size distribution in the green compacts. Sintering behaviour of the powder calcined at 700 °C was found to be marginally poorer in comparison to the other samples, whereas the powder calcined at 800 °C had demonstrated best densification behaviour, especially when compacted at 300 MPa.
Soumyajit Koley, Abhijit Ghosh, Ashok Kumar Sahu, Raghavendra Tewari, Ashok Kumar Suri, Ceramics International 37 (2011) 731–739

A2190 – Preparation of Sr2Fe1–xScxMoO6–? nanopowders and its electrical conductivity

Double-perovskite Sr2Fe1–xScxMoO6–? (x=0, 0.05, 0.1, 0.2, 0.3, 0.4) powders applied to the cathode of solid oxide electrolysis cells were synthesized by the sol-gel citrate combustion method. Initial powders were calcined at different temperatures under different atmosphere (air, H2(4 vol.%)/Ar), and the effects of the preparation process on the structure and the morphology of the powders were investigated by thermal analysis (TG/DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and surface area analysis. The electric conductivity of the materials was measured by electrochemical work station using wafers prepared by dry pressing. It was found that the formation of perovskite structure was related to the content of Sc and combustion improver (NH4NO3), pH value, calcining temperature and atmosphere. A single perovskite phase of Sr2Fe1–xScxMoO6–? could be formed after 3 h calcining in reducing atmosphere of H2 (4 vol.%)/Ar at 1100 °C. The electrical property indicated that, this material had a potential to be used in medium/high temperature solid oxide fuel cells or electrolysis cells.
Ge Ben, AI Desheng, Ma Jingtao, Deng Changsheng, Lin Xuping, Journal of Rare Earths, Vol. 29, No. 7, Jul. 2011, P. 673

A2182 – Synthesis of nanocrystalline Mn–Zn ferrite powders through thermolysis of mixed oxalates

Nanocrystalline Mn–Zn ferrite powders were synthesized by thermal decomposition of an oxalate precursor. Two polymorphs of a mixed Mn–Zn–Fe oxalate dihydrate were obtained by precipitation of metal ions with oxalic acid: monoclinic ?-(Mn, Zn, Fe)3(C2O4)3·6H2O is obtained after precipitation and ageing at 90 °C, whereas the orthorhombic ?-type is formed after precipitation at room temperature. The morphology of the oxalate crystals can be controlled by the precipitation conditions. The ?-polymorph of the mixed oxalate consists of prismatic and agglomerated particles. The ?-oxalate forms non-agglomerated crystallites of submicron size. Thermal decomposition of the oxalate at 350 °C in air results in an amorphous product. Nanosize Mn–Zn ferrite powders are formed at 500 °C and a mixture of haematite and spinel is observed at 750 °C. The thermal decomposition of the mixed oxalate is monitored by thermal analysis, XRD and IR-spectroscopy. The morphology of the oxalate particles is preserved during thermal decomposition; the oxide particle aggregates display similar size and shape as the oxalates. The primary particles are much smaller; their size increases from 3 nm to 50 nm after decomposition of the oxalates at 350 and 500 °C, respectively. The powder synthesized by decomposition at 500 °C was sintered at 1150 °C to dense and fine-grained Mn–Zn ferrites.
Andre Angermann, Jörg Töpfer, Ceramics International 37 (2011) 995–1002

A2178 – One-step microwave synthesis of palladium–carbon nanotube hybrids with improved catalytic performance

A fast and easy one-step linker-free approach for the synthesis of palladium nanoparticle/multiwall carbon nanotube (Pd-NP/MWCNT) hybrid materials is described using microwave irradiation for the effective decomposition of Pd2dba3 complex in the presence of MWCNTs. High loadings of Pd nanoparticles (up to 40 wt.%) having sizes between 3 and 5 nm are deposited on the surface of MWCNTs within a time of only 2 min. The Pd-NP/MWCNT materials serve as efficient catalysts in C–C coupling as well as in hydrogenation reactions, all characterized by high conversion rates using a small amount of catalysts, high turnover frequency values and good recyclability.
Manuela Cano, Ana Benito, Wolfgang K. Maser, Esteban P. Urriolabeitia, Carbon 49 (2011) 652-658

A2174 – The effect of particle size on the formation and structure of carbide-derived carbon on ?-SiC nanoparticles by reaction with chlorine

Carbide-derived carbon (CDC) coatings were produced by reaction with pure chlorine gas on the surface of ?-SiC nanoparticles. Various CDC thicknesses were obtained using moderate temperatures (565–635 °C) associated with a short time (30 min) of chlorination under atmospheric pressure. Such conditions enable controlled layer-by-layer silicon extraction from SiC material. Kinetics of CDC formation were assessed using three SiC laser pyrolysis-produced nanopowders of different average size. Under the same conditions, the smallest particle size material is more prone to chlorination and exhibits a thicker carbon coating. Effect of particle size distribution on reactivity with chlorine is also discussed. After achieving carbide to carbon partial conversion, tem observations show good covering and adherent carbon coatings on remaining SiC material, N2 adsorption analysis show that CDC coating is microporous and has a specific surface area exceeding 1000 m2 g?1. Thermogravimetric analysis coupled with mass spectroscopy under He gas flow, is used to determine the thermal stability and the nature of volatile species trapped in the microporosity. Under an O2 gas flow, the amount of CDC formed is measured by burning it off at temperatures of 400–750 °C, before the onset of oxidation of the remaining SiC.
Benoît Rufino, Stéphane Mazerat, Mathieu Couvrat, Christophe Lorrette, Hicham Maskrot, René Pailler, Carbon 49 (2011) 3073-3083

A2171 – Mechanical and tribological properties of Fe/Cr–FeAl2O4–Al2O3 nano/micro hybrid composites prepared by spark plasma sintering

Fe/Cr–Al2O3 nanocomposite powders are prepared by H2 selective reduction of oxide solid solutions. These powders, an alumina powder and a starting oxide powder, are sintered by spark plasma sintering. The microstructure of the resulting materials is studied. The composites show a lower microhardness and higher fracture strength than unreinforced alumina. The friction coefficient against an alumina ball is lower, revealing the role of the intergranular metal particles, whereas FeAl2O4 grains formed during SPS are beneficial for higher cycle numbers.
J. Gurt Santanach, C. Estournès, A. Weibel, A. Peigney, G. Chevallier, Ch. Laurent, Scripta Materialia 64 (2011) 777–780

A2169 – Synthesis of nanocrystalline lithium niobate powders via a fast chemical route

Lithnium niobate (LiNbO3) can be obtained by mixing lithium nitrate (LiNO3), ammonium niobate oxalate hydrate (C4H4NNbO9) and glycine and then calcining at 600 °C for 1 h. The thermal analysis, structure, and morphology of the as-prepared LiNbO3 were characterized by thermogravimetric and differential thermal analyses (TG/DTA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The crystallization temperature of LiNbO3 precursor is 580 °C based on the TG/DTA results. After being calcined at 600 °C, the structure of the LiNbO3 synthesized using various ratios of glycine to metal nitrates (?-value) was formed with a particle size of about 29–38 nm, as found by XRD analysis. The crystal size has the lowest value at ? = 2, and the highest level of crystallization is at ? = 3
Chia-Liang Kuo, Yee-Shin Chang, Yen-Hwei Chang, Weng-Sing Hwang, Ceramics International 37 (2011) 951–955

A2167 – Oxygen stoichiometry control of nanometric oxide compounds: The case of titanium ferrites

Three techniques have been coupled with an original device, based on H2/H2O equilibrium, controlling oxygen partial pressure: XRD, TGA and DC conductivity in order to characterize very reactive compounds such as nanometric powders. From XRD, both the structure and the oxygen stoichiometry (thanks to their lattice parameter) were investigated in situ. From TGA, it was the oxygen stoichiometry (thanks to mass gain or loss) which was determined. From DC conductivity, it was both the structure and the oxygen stoichiometry (thanks to the activation energy) which were obtained. The advantages were to determine very rapidly and with a small amount of powder the equilibrium conditions (T, pO2) necessary to obtain the desired phase and stoichiometry. These methods have been evaluated for nanometric titanium ferrites. Two phenomena have been observed during the reducing process: the precipitation of a rhombohedral phase and a significant grain growth linked together.
N. Millot, P.Perriat, Journal of Solid State Chemistry 184 (2011) 2776–2784

A2135 – Organo/layered double hydroxide nanohybrids used to remove non ionic pesticides

The preparation and characterization of organo/layered double hydroxide nanohybrids with dodecylsulfate and sebacate as interlayer anion were studied in detail. The aim of the modification of the layered double hydroxides (LDHs) was to change the hydrophilic character of the interlayer to hydrophobic to improve the ability of the nanohybrids to adsorb non-ionic pesticides such as alachlor and metolachlor from water. Adsorption tests were conducted on organo/LDHs using variable pH values, contact times and initial pesticide concentrations (adsorption isotherms) in order to identify the optimum conditions for the intended purpose. Adsorbents and adsorption products were characterized several physicochemical techniques. The adsorption test showed that a noticeable increase of the adsorption of the non-ionic herbicides was produced. Based on the results, the organo/LDHs could be good adsorbents to remove alachlor and metolachlor from water. Different organo/LDHs complexes were prepared by a mechanical mixture and by adsorption. The results show that HTSEB-based complex displays controlled release properties that reduce metolachlor leaching in soil columns compared to a technical product and the other formulations. The release was dependent on the nature of the adsorbent used to prepare the complexes. Thus, it can be concluded that organo/LDHs might act as suitable supports for the design of pesticide slow release formulations with the aim of reducing the adverse effects derived from rapid transport losses of the chemical once applied to soils.
D. Chaara, F. Bruna, M.A. Ulibarri, K. Draoui, C. Barriga, I. Pavlovic, Journal of Hazardous Materials 196 (2011) 350– 359

A2134 – Modification of the properties of carbon nanocoils by different treatments in liquid phase

Carbon nanocoils (CNCs) were synthesized using resorcinol–formaldehyde gel as carbon precursor and a mixture of cobalt and nickel salts as the graphitization catalysts. The last step of the synthesis process involves the elimination of the metals using an oxidative treatment, commonly HNO3 treatment. However, during this treatment not only the metals are eliminated, but also the amorphous and graphitic carbon. On the other hand, this treatment can create surface oxygen groups, modifying the surface chemistry of CNCs. The aim of this work is to study the effect of different oxidative treatments on the final properties of carbon nanocoils in order to obtain materials with high graphitic character. The effect of liquid phase oxidation treatments on the texture, surface chemistry and structure of carbon nanocoils was studied by means of different analytical techniques as N2-physisorption, X-ray diffraction (XRD), temperature programmed oxidation (TPO) and temperature programmed desorption (TPD). During these treatments, surface oxygen groups were created and their number was function of the concentration of the oxidizing agent used and the treatment time.
V. Celorrio, L. Calvillo, S. Pérez-Rodríguez, M.J. Lázaro, R. Moliner, Microporous and Mesoporous Materials 142 (2011) 55–61

A2131 – Optimized network of multi-walled carbon nanotubes for chemical sensing

This work reports the design of a resistive gas sensor based on 2D mats of multi-walled carbon nanotubes (MWCNTs) grown by aerosol-assisted chemical vapour deposition. The sensor sensitivity was optimized using chlorine as analyte by tuning both CNT network morphology and CNT electronic properties. Optimized devices, operating at room temperature, have been calibrated over a large range of concentration and are shown to be sensitive down to 27 ppb of chlorine. The as-grown MWCNT response is compared with responses of 2000?°C annealed CNTs, as well as of nitrogen-doped CNTs and CNTs functionalized with polyethyleneimine (PEI). Under chlorine exposure, the resistance decrease of as-grown and annealed CNTs is attributed to charge transfer from chlorine to CNTs and demonstrates their p-type semiconductor behaviour. XPS analysis of CNTs exposed to chlorine shows the presence of chloride species that confirms electron charge transfer from chlorine to CNTs. By contrast, the resistance of nitrogen-doped and PEI functionalized CNTs exposed to chlorine increases, in agreement with their n-type semiconductor nature. The best response is obtained using annealed CNTs and is attributed to their higher degree of crystallinity
A Gohier, J Chancolon, P Chenevier, D Porterat, M Mayne-L’Hermite, C Reynaud, Nanotechnology 22 (2011) 105501

A2125 – High permeability Ni–Cu–Zn ferrites through additive-free low-temperature sintering of nanocrystalline powders

Nanocrystalline Ni–Cu–Zn ferrite powders Ni0.20Cu0.20Zn0.62Fe1.98O3.99 were prepared by thermal decomposition of an oxalate precursor. The particle size is 6 nm and 350 nm, respectively, for powders obtained through calcinations at 350 °C or 750 °C. The shrinkage behavior significantly changes with particle size; the temperature of maximum shrinkage rate is TMSR = 700 °C for particles of 6 nm size and increases to TMSR = 880 °C for particles 350 nm in size. Dense samples with a permeability of ? = 780 are obtained by sintering at 900 °C for 2 h. Mixtures of nanocrystalline and sub-micron powders allow tailoring of the shrinkage behavior. A maximum permeability of ? = 840 is obtained after sintering of a 1:1-mixture at 900 °C. This demonstrates the potential of nanocrystalline ferrites for co-firing without additives at 900 °C and integration of ferrite inductors into LTCC modules
J. Mürbe, J. Töpfer, Journal of the European Ceramic Society 32 (2012) 1091–1098

A2122 – Surface modification of carbon nanofibers by glycidoxysilane for altering the conductive and mechanical properties of epoxy composites

Carbon nanofibers (CNFs) were functionalized with 3-glycidoxypropyltrimethoxysilane and dispersed into epoxy resin. The chemical modification of CNFs was confirmed by FTIR, SEM, EDX and TGA measurements. After silanization, FTIR showed the existance of epoxy ring; EDX detected Si element; while TGA indicated 1.1 wt.% Si on CNFs. Mechanical properties were analyzed by DMA. Silanized CNFs/epoxy composites demonstrated improved dispersion of CNFs in the matrix, and an enhancement of storage modulus for about 20% compared to the neat matrix, which indicated that the modification of CNFs improved the adhesion between fillers and matrices. DC electrical conductivity of CNFs was reduced about 7-fold compared to the original CNFs due to the silane coating. Accordingly, the composites containing silanized CNFs also had lower electrical conductivity than those containing original CNFs. In spite of decreased electrical conductivity, thermal conductivity of silanized CNFs/epoxy composites was increased due to the surface modification of CNFs.
Yaru Nie, Thomas Hübert, Composites: Part A 43 (2012) 1357–1364

A2119 – Hard nanocomposite coatings: Thermal stability, oxidation resistance and toughness

The article reports on the enhanced hardness of nanocomposite coatings, their thermal stability, protection of the substrate against oxidation at temperatures above 1000 °C, X-ray amorphous coatings thermally stable above 1000 °C and new advanced hard nanocomposite coatings with enhanced toughness which exhibit (i) low values of the effective Young's modulus E? satisfying the condition H/E? > 0.1, (ii) high elastic recovery We ? 60%, (iii) strongly improved tribological properties, and (iv) enhanced resistance to cracking; here E? = E(1??2), E is the Young's modulus and ? is the Poison's ratio. At the end trends of next development of hard nanocomposite coatings are briefly outlined.
J. Musil, Surface & Coatings Technology 207 (2012) 50–65

A2116 – Synthesis of clay–carbon nanotube hybrids: Growth of carbon nanotubes in different types of iron modified montmorillonite

In the present study, montmorillonite–carbon nanotube hybrids were synthesized by catalytic decomposition of ethylene over iron montmorillonite surfaces modified by different experimental procedures. SEM and STEM analyses reveal the presence of carbon nanotubes attached to the clay layers and X-ray diffraction results indicate that sodium montmorillonite layers were intercalated with iron species during the ion-exchange processes and further delaminated due to the growth of carbon nanotubes. It is expected that montmorillonite–carbon nanotube hybrids will be beneficiary for improvement of mechanical properties in polymer nanocomposites due to their pre-exfoliated internal structure and the presence of surface carbon nanotubes which may significantly enhance reinforcing effect.
Liliana Madaleno, Ryszard Pyrz, Lars R. Jensen, José J.C. Pinto, Augusto B. Lopes, Viktoriya Dolomanova, Jan Schjødt-Thomsen, Jens Chr.M. Rauhe, Composites Science and Technology 72 (2012) 377–381

A2110 – Effects of Cationic Surfactant in Sol-gel Synthesis of Nano Sized Magnesium Oxide

In this study, sol-gel method was used to synthesize nano sized of magnesium oxide (MgO). Magnesium acetate tetrahydrate and tartaric acid have been dissolved in ethanol and formed a precursor before calcined at 600 ¡C for 6 h to produce MgO nanoparticles. A cationic surfactant (cetyltrimethylammonium bromide, CTAB) had used in the sol-gel reaction to reduce agglomeration of the nanoparticles. Two samples (MgO and MgO-CTAB) were characterized using simultaneous thermogravimetric analyzer (STA), X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM) and nitrogen adsorption-desorption measurement. Formation of the samples via a sol-gel route is discussed and confirmed using the STA results. The precursor formed was identified as magnesium tartrate and decomposed to MgO and MgO-CTAB after the calcinations, and gave a single phase of samples as shown by the XRD patterns. The used of CTAB in this sol-gel method gives the MgO nanoparticles with less agglomeration. This was proved by the FESEM micrographs, the MgO-CTAB has spherical shape and the agglomeration seems to be less than the MgO. It suggests that the cationic surfactant controls the morphology of the samples.
Mohd Sufri Mastulia, Noor Sabrina Ansari, Mohd Azizi Nawawi, Annie Maria Mahat, APCBEE Procedia 3 ( 2012 ) 93 – 98

A2109 – The functionalization of carbon nanotubes using a batch oscillatory flow reactor

This paper describes an efficient method for the functionalizing of multi-walled carbon nanotubes (MWCNT) using oscillatory flow mixing (OFM). A 3 l batch oscillatory flow reactor (OFR) was designed and constructed for pilot scale functionalization of MWCNT in order to potentially improve their compatibility within a thermoplastic polyphenylene sulphide (PPS) matrix. The OFM batch reactor consisted of a jacketed cylindrical vessel with a vertical axial oscillator that contained a series of baffled mixing plates. MWCNTs dispersed in dimethylformamide (DMF) were introduced into the reactor and a two stage reaction for functionalizing MWCNTs with PPS compatible groups was carried out under oscillation of baffles at elevated temperatures. Fluid mixing observations in the reactor showed that MWCNTs formed a uniform dispersion of aggregated flocs before and during the functionalization reaction. On completion of the reaction and cessation of the oscillation, the aggregated flocs of MWCNT rapidly sedimented at the bottom of the reactor; hence could be collected as a concentrated mass thereby facilitating the separation of functionalized MWCNTs from the solvent. The functionalized MWCNTs were dried and then characterized by transmission electron microscopy, infrared spectroscopy as well as thermal gravimetric analysis in order to investigate the extent of MWCNT functionalization. The characterization results confirmed the effective and relatively uniform functionalization of the MWCNTs despite formation of aggregates, indicating that OFM provides a viable approach for functionalizing MWCNTs.
S. Melendi, S.Bonyadi, P.Castell, M.T.Martinez, M.R.Mackley, Chemical Engineering Science 84 (2012) 544–551

A2107 – Synthesis and functionalization of persistent luminescence nanoparticles with small molecules and evaluation of their targeting ability

We have recently reported the design and use of inorganic nanoparticles with persistent luminescence properties. Such nanoparticles can be excited with a UV lamp for 2 min and emit light in the near-infrared area for dozen of minutes without any further excitation. This property is of particular interest for small animal optical imaging, since it avoids the autofluorescence of endogenous fluorophores which is one major problem encountered when using fluorescent probes. We report herein the synthesis of persistent luminescence nanoparticles (PLNPs) and their functionalization with two small targeting molecules: biotin and Rak-2. We provide characterization of each PLNP as well as preliminary evidence of the ability of PLNP-PEG-Biotin to target streptavidin and PLNP-PEG-Rak-2 to bind prostate cancer cells in vitro.
Thomas Maldiney, Gerardo Byk, Nicolas Wattier, Johanne Seguin, Raz Khandadash, Michel Bessodes, Cyrille Richard, Daniel Scherman, International Journal of Pharmaceutics 423 (2012) 102– 107

A2097 – Synthetics of ZnO nanowires on GaN micro-pyramids by gold catalyst

GaN micro-pyramids were fabricated on n-type CaN buffer layer/c-plane sapphire wafer. In order to understand the growing ZnO on GaN {1–1 0 1} facets, ZnO nanostructures on GaN micro-pyramids with and without Au catalyst were synthesized by chemical vapor deposition (CVD). As-prepared ZnO nanostructures were characterized by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). ZnO nano-sheets on the micro-pyramids without Au catalyst have a terrace-like structure, which is explained by vapor–solid mechanism. ZnO nanowires with a gold particle on the top grow on micro-pyramids with Au catalyst, which is explained by vapor–liquid–solid mechanism. Nanowire bridges crosslinking two adjacent micro-pyramids are frequently observed, which demonstrates the capability to develop self-organizing electrical interconnects and nanoscale devices. The diameters of the resulting ZnO nanowires are in the range of 40–100 nm with typical length about 10 ?m.
C.H. Xu, K. Leung, J. Hu, C. Surya, Materials Letters 74 (2012) 100–103

A2085 – Size controlled copper nanoparticles hosted in mesoporous silica matrix: Preparation and characterization

A novel preparation strategy was performed to obtain uniform and size controlled, in a large scale, copper nanoparticles, hosted into mesoporous silica matrix. The method includes the initial deposition of finely dispersed copper nanoparticles, using a conventional incipient wetness impregnation of silica matrix with small amount of nitrate precursor and consecutive pretreatment in oxidation and reduction atmosphere. The further controlled growing of the loaded copper particles was performed in rotary bed reactor by step-wise deposition of copper over them by OMCVD techniques, using bis- (hexafluoroacetylacetonate) copper (II) hydrate as a precursor. A complex of physicochemical methods (TEM, Nitrogen physisorption, TPR and TPRD-MS measurements, UV-Vis and FTIR spectroscopy of adsorbed CO) was used for characterization of the samples. The catalytic properties of the obtained materials were investigated in methanol decomposition to CO and hydrogen. A mechanism of the copper particles growing was discussed. Size dependent effects of the redox and catalytic properties of the loaded copper particles which are strongly affected by their location in the silica porous structure are assumed
Alessandro Gallo, Tanya Tsoncheva, Marcello Marelli, Mihail Mihaylov, Momtchil Dimitrov, Vladimiro Dal Santo, Konstantin Hadjiivanov, Applied Catalysis B: Environmental 126 (2012) 161– 171

A2083 – Synthesis and electrochemical performance of LiV3O8/polyaniline as cathode material for the lithium battery

LiV3O8–polyaniline nanocomposites have been synthesized via chemical oxidative polymerization directed by the anionic surfactant sodium dodecyl benzene sulfate. The polyaniline particles are uniformly coated on the LiV3O8 nanorods. The composite with 12 wt.% polyaniline retains a discharge capacity of 204 mAh g?1 after 100 cycles and had better rate capability (175 mAh g?1 at 2 C and 145 mAh g?1 at 4 C) than the bare LiV3O8 electrode in the potential range of 1.5–4.0 V. The polyaniline coating can buffer the dissolution into the LiPF6 electrode that occurs in LiV3O8 during cycling. The charge transfer resistance of the composite electrode was much lower than that of the bare LiV3O8 electrode, indicating that polyaniline coating significantly increases the electrical conductivity between the LiV3O8 nanorods. Polyaniline is a conductive binder which buffers the dissolution of LiV3O8 into the electrolyte and reduces the contact resistance among nanorods, so performance of the composite is significantly improved
Xuan-Wen Gao, Jia-Zhao Wang, Shu-Lei Chou, Hua-Kun Liu, Journal of Power Sources 220 (2012) 47-53

A2068 – Exceptional arsenic adsorption performance of hydrous cerium oxide nanoparticles: Part A. Adsorption capacity and mechanism

Hydrous cerium oxide (HCO) nanoparticles were synthesized by a simple precipitation process, and their arsenic adsorption performances were investigated. Due to their high specific surface area (198 m2/g) and the presence of high affinity surface hydroxyl groups, HCO nanoparticles demonstrated exceptional adsorption properties in terms of adsorption capacity and kinetics on both As(III) and As(V). At neutral pH, the arsenic adsorption capacity of HCO reached over 170 mg/g for As(III) and 107 mg/g for As(V). Even at very low equilibrium arsenic concentrations, the amount of As(III) and As(V) adsorbed by HCO nanoparticles was still over 13 mg/g at 10 ?g/L and over 40 mg/g at 50 ?g/L, which are higher than the arsenic adsorption capacity for most commercial adsorbents. Over a wide pH range from 3 to 11, HCO nanoparticles could readily remove As(III) by adsorption, which was not observed previously on other arsenic adsorbents. Such exceptional arsenic adsorption properties by HCO nanoparticles were shown to derive from the strong inner-sphere complexion
Ronghui Li, Qi Li, Shian Gao, Jian Ku Shang, Chemical Engineering Journal 185– 186 (2012) 127– 135

A2058 – Development of high concentrated aqueous silver nanofluid and inkjet printing on ceramic substrates

In this paper, the formulation of a high Ag loading (45 wt%) aqueous ink and its subsequent printing on three different ceramic substrates were reported. Monodispersed Ag nanoparticles with a size down to 10 nm were successfully synthesized in aqueous medium. These nanoparticles were then successfully dispersed up to 45 wt% in aqueous medium with the aid of a co-polymer, Pluronic F127. The printed tracks show the electrical conductivity of 3 ?? cm close to the value of silver bulk (1.6 ?? cm). The use of high solid loading inks reduces the number of printed layers required for thick, dense and conductive film thus leading to the reduction of the costs, and high efficiency of the printing process. High solid loading also results in the finer printed features. The effect of substrates, printing temperature and dot spacing on the size and morphology of printed silver features was investigated. Increasing the dot spacing together with the substrates temperature resulted in the limited ink spreading, hence narrow printed line and improved geometry of printed patterns
A. Kosmala, Q. Zhang, R. Wright, P. Kirby, Materials Chemistry and Physics 132 (2012) 788– 795

A2039 – Synthesis and characterization of Pd-poly(N-vinyl-2-pyrrolidone)/KIT-5 nanocomposite for Heck reaction

Pd-poly(N-vinyl-2-pyrrolidone)/KIT-5 nanocomposite was prepared and characterized by XRD, FT-IR, UV–vis, BET and TEM techniques. The catalytic performance of this novel heterogeneous catalyst was determined for Heck reaction. Its stability was excellent and it could be reused eight times without much loss of activity in Heck reaction.
Roozbeh Javad Kalbasi, Neda Mosaddegh, Materials Research Bulletin 47 (2012) 160–166

A2026 – Nanocasting, Template Synthesis, and Structural Studies on Cesium Salt of Phosphotungstic Acid for the Synthesis of Novel 1,3,5-Triaryl-pyrazoline Derivatives

The elimination of the silica matrix of composites by HF occurred by a two-step reaction deposition of a Cs2.5H0.5PW12O40 (CsHPW) salt nanocrystal. We used 2D hexagonal SBA-15 silica as a template for the nanofabrication of CsHPW nanoparticles. Nanocast CsHPW materials are stable against leaching and colloidization in polar solvents. The catalytic performance of the nanocast CsHPW materials exceeded that of bulk Cs2.5H0.5PW12O40, which is the most active among the acidic HPW salts. A series of novel 1,3,5-triaryl-pyrazoline derivatives were synthesized by the reaction between chalcone and phenylhydrazine in high yield in the presence of CsHPW salt nanocrystals
Razieh Fazaeli, Hamid Aliyan, Shahram Tangestaninejad, Esmaeel Mohammidi, Maryam Bordbar, Chinese Journal of Catalysis, Volume 33, Issue 2, 2012

A2022 – Crystallinity of nano C-LiFePO4 prepared by the polyol process

Size and shape-tuned LiFePO4 nano-platelets were prepared by the polyol process to examine the effect of their microstructure on their electrochemical performance when coated by a thin carbon layer. The materials were characterized by X-ray diffraction, scanning and transmission electron microscopy, magnetic susceptibility, Fourier transform infrared and Raman spectroscopy. The crystallinity, as well as the size of the particles, depends on the nature of the solvent that is used, and also on the rate of dilution. The electrochemical properties emphasize the role of antisite defects and the coherence length along the b-axis, i.e. along the Li channels. With an optimized choice of the synthesis parameters, the results showed that the orthorhombic olivine structure is retained even in crystals of few nanometers in width, a free of impurities. The high crystalline quality of the particles obtained in these optimized conditions lead to a good electrochemical performance of the nanocomposite C-LiFePO4 product as a cathode material for lithium-ion batteries, with a capacity 151 mAh g?1 at low C-rate, despite the presence of residual adsorbed polyol species that are found to be insulating.
T. Azib, S. Ammar, S. Nowak, S. Lau-Truing, H. Groult, K. Zaghib, A. Mauger, C.M. Julien, Journal of Power Sources 217 (2012) 220e228

A2021 – Effect of different nanoparticles on thermal decomposition of poly(propylene sebacate)/nanocomposites: Evaluation of mechanisms using TGA and TG–FTIR–GC/MS

In the present study poly(propylene sebacate) (PPSeb) nanocomposites containing 2 wt% of fumed silica nanoparticles (SiO2) or multiwalled carbon nanotubes (MWCNTs), or montmorillonite (MMT) were prepared by in situ polymerization. The thermal degradation of nanocomposites was studied using thermogravimetric analysis (TGA). It was found that the addition of MWCNTs and MMT enhances the thermal stability of the polymer, while SiO2 nanoparticles do not affect it. From the variation of the activation energy (E) with increasing degree of conversion it was found that the decomposition of nanocomposites proceeded with a complex reaction mechanism with the participation of at least two different steps. To evaluate the thermal decomposition mechanisms and mainly the effect of nanoparticles on the thermal decomposition of PPSeb, TGA/FTIR and a combination of TG-gas chromatography–mass spectrometry (TG/GC–MS) were used. From mass ions detection of the formed decomposition compounds it was found that the decomposition of PPSeb and its nanocomposites, takes place mainly through ?-hydrogen bond scission and, secondarily, through ?-hydrogen bond scission. The main decomposition products were aldehydes, alcohols, allyl, diallyl, and carboxylic acids
K. Chrissafis, E. Roumeli, K.M. Paraskevopoulos, N. Nianias, D.N. Bikiaris, Journal of Analytical and Applied Pyrolysis 96 (2012) 92–99

A2015 – Multisite luminescence of rare earth doped TiO2 anatase nanoparticles

Eu3+, Sm3+ and Tb3+ ions have been incorporated into anatase TiO2 nanocrystals via hydrolytic sol–gel method. Pure anatase phase was confirmed with XRD and TEM measurements. Band gap energies change slightly with rare earth incorporation, from 3.32 eV for undoped TiO2 to 3.15 eV, 3.25 eV and 3.29 eV for Tb3+, Sm3+ and Eu3+ doped TiO2. Photoluminescence of Eu3+ and Sm3+ originated from three different sites in TiO2 nanocrystals have been identified with the laser-excited site-selective spectroscopy measurements at 10 K. One site exhibits broad emission peaks, which are ascribed to the distorted lattice site near the surface. Other two sites, associated with the inner lattice, show significantly sharper fluorescence lines as a consequence of an ordered crystalline environment. The emission decays of Eu3+ and Sm3+ have similar values for inner-lattice sites and longer lifetimes for near-surface sites. The luminescence of Tb3+ doped TiO2 nanocrystals was immeasurably weak.
Zeljka Antic, Radenka M. Krsmanovic, Marko G. Nikolic, Milena Marinovic-Cincovi, Miodrag Mitric, Stefano Polizzi, Miroslav D. Dramicanin, Materials Chemistry and Physics 135 (2012) 1064-1069

A2005 – Critical role of surface chemical modifications induced by length shortening on multi-walled carbon nanotubes-induced toxicity

Given the increasing use of carbon nanotubes (CNT) in composite materials and their possible expansion to new areas such as nanomedicine which will both lead to higher human exposure, a better understanding of their potential to cause adverse effects on human health is needed. Like other nanomaterials, the biological reactivity and toxicity of CNT were shown to depend on various physicochemical characteristics, and length has been suggested to play a critical role. We therefore designed a comprehensive study that aimed at comparing the effects on murine macrophages of two samples of multi-walled CNT (MWCNT) specifically synthesized following a similar production process (aerosol-assisted CVD), and used a soft ultrasonic treatment in water to modify the length of one of them. We showed that modification of the length of MWCNT leads, unavoidably, to accompanying structural (i.e. defects) and chemical (i.e. oxidation) modifications that affect both surface and residual catalyst iron nanoparticle content of CNT. The biological response of murine macrophages to the two different MWCNT samples was evaluated in terms of cell viability, pro-inflammatory cytokines secretion and oxidative stress. We showed that structural defects and oxidation both induced by the length reduction process are at least as responsible as the length reduction itself for the enhanced pro-inflammatory and pro-oxidative response observed with short (oxidized) compared to long (pristine) MWCNT. In conclusion, our results stress that surface properties should be considered, alongside the length, as essential parameters in CNT-induced inflammation, especially when dealing with a safe design of CNT, for application in nanomedicine for example.
Cyrill Bussy, Mathieu Pinault, Julien Cambedouzou, Marion Julie Landry, Pascale Jegou, Martine Mayne-L'hermite, Pascale Launois, Jorge Boczkowski, Sophie Lanone, Particle and Fibre Toxicology 2012, 9:46

A2004 – Study of the energy absorption capabilities of laminated glass using carbon nanotubes

Laminated glass (LG) typically consists of two or more glass plies bonded together with a transparent thermoplastic elastomeric interlayer, often composed of polyvinyl butyral (PVB). This interlayer primarily serves as a means of preventing splintering and of absorbing energy upon blast/impact. This research attempted to enhance the impact resistance of LG by increasing PVB interlayer energy absorption by embedding carbon nanotubes (CNTs). Interlayers were formed by electrospinning aligned PVB fibers mat embedded with various concentrations of CNTs. Subsequently, the fiber mat was hot-pressed between two glass plies forming a composite film. The composite fibers were characterized using optical, SEM, and TEM microscopy. The mechanical and thermo-mechanical properties of fibers were determined by dynamic mechanical analysis (DMA), and the energy absorption capacities of the modified LGs were measured by applying the Charpy impact test of un-notched samples. A ? 30% increase in composite fiber (CNT 1.5 wt.%) strength was observed, along with a ? 70% increase in elastic modulus, measured at a strain rate of 0.1 min?1, in comparison to CNT-free fibers. Increased CNT loading restricted the segmental motion of polymer macromolecules and provided the geometrical confinement effect to neighboring macromolecules in the nanoscale fiber. The energy absorption of a double-layered LG embedded with carbon nanotubes increased by nearly 341%, where experimental results demonstrated the role of the CNTs pull-out toughening mechanism. In parallel, transmission of visible light decreased by 60%.
Dimitry Alhazov, Eyal Zussman, Composites Science and Technology 72 (2012) 681–687

A2003 – Arsenic(V) removal from underground water by magnetic nanoparticles synthesized from waste red mud

In this study waste red mud (bauxite residue) sample obtained from Seydi?ehir (Konya, Turkey) was evaluated for the synthesis of Fe3O4 nanoparticles (NPs) in ammonia solution that can be used to remove As(V) from both synthetic and natural underground water samples. The synthesized Fe3O4-NPs were characterized by using TEM, VSM, XRD, SAXS, TGA and FT-IR spectroscopy. The Fe3O4-NPs assumed a near-sphere shape with an average size of 9 nm. The results showed that synthesized Fe3O4-NPs from waste red mud have satisfactory magnetic properties and As(V) sorption capacity, especially at low equilibrium arsenate concentrations
Ilker Akin, Gulsin Arslan, Ali Tor, Mustafa Ersoz, Yunus Cengeloglu, Journal of Hazardous Materials 235– 236 (2012) 62– 68

A2002 – Synthesis, characterization and electrical proprieties study of layered benzyltrimethylammonium–vanadium pentoxide nanocomposites

Plate-like benzyltrimethylammonium-vanadium pentoxide intercalate compound have been synthesized by hydrothermal method. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermal analysis techniques, and Raman spectroscopy have been used to characterize the structure, morphology and composition of the plates. The material has a layered structure with an interlayer spacing of about 1.369 nm. The width of the plates varies between 80 and 250 nm and a thickness around 40 nm. The influences of the reaction time on the morphology have been investigated. The electronic conductivity measurements show that the conductivity curve is described by an Arrhenius law with activation energy of 0.46 eV.
M.K. Chine, F. Sediri, N. Gharbi, M. Jouini, Materials Letters 71 (2012) 101–103

A2001 – Influence of surface modified TiO2 nanoparticles by gallates on the properties of PMMA/TiO2 nanocomposites

Nanocomposites based on poly(methyl methacrylate) (PMMA) and TiO2 nanoparticles were synthesized by in situ radical polymerization of MMA in solution. The surface of TiO2 nanoparticles was modified with four gallic acid esters (octyl, decyl, lauryl and cetyl gallate). The content of gallates present on the surface of TiO2 was calculated from the TGA results. The influence of length of hydrophobic tail of amphiphilic alkyl gallates on dispersability of surface modified TiO2 nanoparticles in PMMA matrix, the molecular weight and glass transition temperature of PMMA, as well as the thermal stability of the prepared PMMA/TiO2 nanocomposites in nitrogen and air was investigated. The influence of content of TiO2 nanoparticles on the properties of these nanocomposites was also examined. The formation of a charge transfer complex between the surface Ti atoms and the gallates was confirmed by FTIR and UV spectroscopy. TEM micrographs of the PMMA/TiO2 nanocomposites revealed that degree of TiO2 aggregation can be significantly lowered by increasing the length of aliphatic part of the used gallates. The molecular weight of PMMA slightly decreases with the increase of TiO2 content, indicating that used TiO2 nanoparticles act as radical scavengers during the polymerization of MMA. The presence of surface modified TiO2 nanoparticles do not have an influence on the mobility of PMMA chain segments leading to the same values of glass transition temperature for all investigated samples. Thermal and thermo-oxidative stability of the PMMA matrix are improved by introducing TiO2 nanoparticles modified with gallates.
Enis S. Dzunuzovic, Jasna V. Dzunuzovic, Aleksandar D. Marinkovic, Milena T. Marinovic-Cincovic, Katarina B. Jeremic, Jovan M. Nedeljkovic, European Polymer Journal 48 (2012) 1385–1393

A1977 – Low-frequency Raman study of hollow multiwalled nanotubes grown by Fe catalyzed chemical vapor deposition

In this work, it is shown that some Raman-active modes may be detected, below 500 cm?1, in the spectrum of nanotubes synthesized by iron catalyzed chemical vapor deposition. By comparatively discussing results of Raman, high-resolution transmission electron microscopy, and thermogravimetric analyses, demonstration is given that these spectral features originate from scattering by nanoparticles of iron catalyst encapsulated within the tubes under nonstationary growth regime. Their intensity progressively weakens with increasing carbon supply rate until bands disappear as stationary conditions are reached.
S. Santangelo, G. Messina, M. G. Donato, M. Lanza, C. Milone, Journal of Applied Physics 100, 104311 2006

A1976 – Nitrogen Containing Carbon Nanofibers as Non-Noble Metal Cathode Catalysts in PEM and Direct Methanol Fuel Cells

PEM and direct methanol fuel cells (DMFC) have great potential for use as alternative fuel energy conversion devices. Before this potential can be realized, however, performance improvements must be made and material costs need to be reduced. The limiting reaction in the PEMFCs and DMFCs is the oxygen reduction reaction (ORR), which occurs at the cathode. In an attempt to improve the reaction kinetics, substantial loadings of Pt catalysts are required on the cathode. This significantly increases the overall cost of the fuel cell. Also, in DMFCs, methanol crossover from the anode allows for competing reactions at the cathode catalyst to occur, reducing the power output of the fuel cell further. As the demand for fuel cells increase, the demand for Pt will far outpace the supply of Pt.
Elizabeth Joyce Biddinger, Dissertation, The Ohio State University, 2010

A1974 – Studies on the thermal decomposition of multiwall carbon nanotubes under different atmospheres

Carbon nanotubes (CNTs) have unique physical properties. This has been the driver for the current exploitation of their use in different advanced applications, such as in composite nanoscale devices. If a thermal treatment is required for the fabrication of the composite, the thermal decomposition behavior of the tubes is a key aspect in the integration process. Within this context, the thermal decomposition of multiwall CNTs (MWCNTs) under different conditions was studied in this work by DTA/TG, XRD, RAMAN spectroscopy and electron microscopy. Purified MWCNTs are stable up to 420 °C in air, as no weight loss occurs in TG/DTA analysis under non isothermal conditions but morphology changes were observed for isothermal conditions at 400 °C by Raman spectroscopy. In oxygen-rich atmosphere MWCNTs started to oxidized at 200 °C. However in argon-rich atmosphere and under a high heating rate MWCNTs remain stable up to 1300 °C with a minimum sublimation. The activation energy for the decomposition of MWCNTs in air was calculated to lie between 80 and 108 kJ/mol. These results have broad implications for the expanded use of MWCNTs in composites with functional complex oxides that usually require synthesis temperature above 650 °C.
Amit Mahajan, Angus Kingon, Akos Kukovecz, Zoltan Konya, Paula M.Vilarinho, Materials Letters 90 (2013) 165–168

A1973 – Combustion synthesis route to carbon-encapsulated iron nanoparticles

A new self-induced and efficient route to carbon-encapsulated iron nanocrystallites (ca. 30–60 nm in diameter) using the thermolysis of sodium azide–chlorocarbon mixtures in the presence of ferrocene is presented. The product was purified and its composition and morphology were studied by means of HR SEM, HR TEM, XRD, and DTA/TG. The magnetic properties (the coercivities ca. 60–70 Oe and the saturation magnetization ca. 21–22 emu/g) of encapsulates were measured. This autothermal process has inherent advantages, including the use of low cost materials and the simplicity of the production protocol, and can be also used to obtain other nanoencapsulates.
Micha? Bystrzejewski, Andrzej Huczko, Hubert Lange, Stanis?aw Cudzi?o, Wojciech Kici?ski, Diamond & Related Materials 16 (2007) 225–228

A1972 – Thermal stability of carbon-encapsulated Fe–Nd–B nanoparticles

Thermal stability of various magnetic nanomaterials is very essential, due to their prospective future applications. In this paper, thermal behaviour of the carbon-encapsulated Fe–Nd–B nanoparticles is studied. These nanostructures were produced by direct current arcing of carbon anodes filled with Nd2Fe14B material. The thermogravimetry and differential thermal analysis curves were recorded in an oxygen atmosphere. The thermal processes were monitored by X-ray diffraction to follow the changes in the phase composition. The investigated samples have been thermally stable up to 600 K.
M. Bystrzejewski, S. Cudzi?o, A. Huczko, H. Lange, Journal of Alloys and Compounds 423 (2006) 74–76

A1966 – In situ high-temperature Mössbauer spectroscopic study of carbon nanotube–Fe–Al2O3 nanocomposite powder

The oxidation of a carbon nanotube–Fe–Al2O3 nanocomposite powder was investigated using notably thermogravimetric analysis, room temperature transmission and emission Mössbauer spectroscopy and, for the first time, in situ high-temperature transmission Mössbauer spectroscopy. The first weight gain (150–300°C) was attributed to the oxidation into hematite of the ?-Fe and Fe3C particles located at the surface and in the open porosity of the alumina grains. The 25nm hematite particles are superparamagnetic at 250°C or above. A weight loss (300–540°C) corresponds to the oxidation of carbon nanotubes and graphene layers surrounding the nanoparticles. The graphene layers surrounding ?-Fe–C particles are progressively oxidized and a very thin hematite layer is formed at the surface of the particles, preventing their complete oxidation while helping to retain the face-centered cubic structure. Finally, two weight gains (670 and 1120°C) correspond to the oxidation of the intragranular ?-Fe particles and the ?-Fe–C particles.
Valdirene G. de Resende, Alain Peigney, Eddy De Grave, Christophe Laurent, Thermochimica Acta 494 (2009) 86–93

A1961 – Structural and thermal properties of boron nitride nanoparticles

In the present study, our main motivation was to investigate the structural and thermal stability of BN nanoparticles (B1.0N0.9-NPs) produced by spray-pyrolysis (SP) of borazine at 1400°C by thermogravimetric experiments and X-ray diffraction. We observed that B1.0N0.9-NPs are relatively stable in air below 850°C in which only oxidation of the NP surface proceeded. Above 850°C, the powders started to strongly react with air due to bulk oxidation. Under nitrogen, they appeared to be less stable than plate-like BN synthesized from borazine at 1400°C through conventional pyrolysis. This is related to the low degree of crystallization of B1.0N0.9-NPs that clearly affects their stability. Using a post-pyrolysis treatment at 1400°C, B1.0N0.9-NPs remained stable up to 1600°C similarly to plate-like BN. However, above 1600°C, a relatively fast weight loss occurred for B1.0N0.9-NPs, whereas plate-like BN remained stable up to 1800°C. This indicated that their lower size also affects their high temperature thermal behavior.
V. Salles, S. Bernard, R. Chiriac, P. Miele, Journal of the European Ceramic Society 32 (2012) 1867–1871

A1960 – Mécanismes de croissance de nanotubes de carbone alignés : relation catalyseur – nanotube

Dans le domaine des nanosciences qui est actuellement en plein essor, les nanotubes de carbone (NTC) suscitent un fort intérêt en raison de leurs propriétés originales qui résultent de leur structure particulière. Pour maîtriser et optimiser les procédés de fabrication, il est essentiel de comprendre les mécanismes qui régissent leur croissance. Parmi les techniques de synthèse des NTC, la CCVD (Catalytic Chemical Vapor Deposition) d’aérosol, développée au laboratoire Francis Perrin, permet la croissance rapide et continue de NTC multi-feuillets alignés et propres par l’injection simultanée de précurseur carboné liquide (toluène) et catalytique (métallocène). Notre principal objectif a été de comprendre comment le métallocène donne naissance à la particule catalytique, quelle est la nature exacte de celle-ci, quels sont les paramètres qui contrôlent son activité et enfin comment les espèces catalytiques cheminent pour permettre la croissance des NTC. Grâce à une approche expérimentale faisant intervenir une étude systématique des produits le long du four pour différentes conditions thermodynamiques (flux et mode de refroidissement) et chimiques (concentration en précurseurs, introduction de gaz réducteur), nous avons mis en évidence une germination homogène des particules de fer en phase gazeuse se produisant en amont de la zone isotherme suivie de leur dépôt graduel le long du four. Les particules catalytiques à la base du tapis de NTC alignés seraient un fer semi-fondu sursaturé en carbone qui est alimenté en continu par les espèces catalytiques qui diffusent le long du tapis de NTC jusqu’à sa base.
Celia CASTRO, Thèse Université Paris XI Orsay, Décembre 2009

A1959 – Carbon nanotubes produced by fluidized bed catalytic CVD: first approach of the process

Multi-walled carbon nanotubes have been produced with high yield on an iron supported catalyst by catalytic chemical vapor deposition in a $uidized bed reactor. The choice of such a technique allows to reach high selectivity towards the desired material. A remarkable feature of this process is the huge bed expansion observed during the nanotubes growth that a
M. Corrias, B. Caussat, A. Ayral, J. Durand, Y. Kihn, Ph. Kalck, Ph. Serp, Chemical Engineering Science 58 (2003) 4475 – 4482

A1958 – Identification of key parameters for the selective growth of single or double wall carbon nanotubes on FeMo/Al2O3 CVD catalysts

The successive organometallic chemical vapor deposition of metallic molybdenum and then iron from their carbonyl precursors at 220°C on ?-alumina results in the formation of a bi-layered film on the alumina surface. These catalysts might be active for the selective synthesis of single or double wall carbon nanotubes from methane at 900°C provided that (i) a fine tuning of the activation step is performed and (ii) the gas phase composition is carefully controlled. The negative influence of nitrogen on the selectivity towards SWCNT and DWCNT has been evidenced. Addition of hydrogen is harmful to SWCNT growth, whereas a low partial pressure of hydrogen is necessary to grow selectively DWCNT. These results can be rationalized in terms of kinetics of reduction of the active catalytic species. Based on XRD, Raman spectroscopy, XPS, FESEM/EDX and TEM analyses, a general pathway for SWCNT formation on the FeMo/Al2O3 CVD catalysts is proposed that involves the active mixed FeMoO4 oxide phase.
Emmanuel Lamouroux, Philippe Serp, Yolande Kihn, Philippe Kalck, Applied Catalysis A: General 323 (2007) 162–173

A1957 – A parametric study of the large scale production of multi-walled carbon nanotubes by fluidized bed catalytic chemical vapor deposition

A parametric study investigating the impact of temperature, run duration, total pressure, and composition of the gaseous phase on the catalytic growth of multi-walled carbon nanotubes (MWCNT) has been performed. MWCNTs have been produced very selectively on the multi-gram scale by catalytic chemical vapor deposition from ethylene in a fluidized bed reactor. The kinetics of MWCNTs growth is fast and, with the catalyst used, no induction period has been observed. The kinetic law is of positive order in ethylene concentration and the process is limited by internal diffusion in the porosity of the catalyst. The formation of MWCNTs in the macroporosity of the catalyst induces an explosion of the catalyst grains. Such a process, thanks to the absence of temperature gradient and to the efficient mixing of the grains allows a uniform and selective treatment of the catalyst powder leading to very high selectivity towards MWCNTs formation. High purity MWCNTs have been obtained after catalyst dissolution. Depending on the temperature of production, the specific surface area of this material ranged between 95 and 455 m2/g.
Aurore Morançais, Brigitte Caussat, Yolande Kihn, Philippe Kalck, Dominique Plee, Patrice Gaillard, Daniel Bernard, Philippe Serp, Carbon 45 (2007) 624–635

A1956 – MWCNT activation and its influence on the catalytic performance of Pt/MWCNT catalysts for selective hydrogenation

Multi-walled carbon nanotubes were submitted to three activation procedures: nitric acid oxidation, ball-milling and air oxidation. The influence of these treatments on nanotubes surface chemistry and morphology was evaluated by XPS, Raman and infrared spectroscopy, TGA, TPD, nitrogen adsorption and TEM. The three activated materials were used to prepare Pt supported catalysts from the organometallic precursor [Pt(CH3)2(COD)]. The influence of the activation treatments, together with that of a post-reduction thermal treatment, on the performances of the catalytic systems in the selective hydrogenation of cinnamaldehyde was investigated. It was shown that the best compromise between catalyst activity and selectivity requires a low amount of oxygenated groups on the support surface of the final catalyst, typically less than 700 lmol/g CO + CO2 evolved during TPD experiments, together with an optimized platinum particle size ranging between 10 and 20 nm.
A. Solhy, B.F. Machado, J. Beausoleil, Y. Kihn, F. Gonçalves, M.F.R. Pereira, J.J.M. Orfao, J.L. Figueiredo, J.L. Faria, P. Serp, Carbon 46 (2008) 1194-1207

A1955 – Dynamics of catalyst particle formation and multi-walled carbon nanotube growth in aerosol-assisted catalytic chemical vapor deposition

In aerosol-assisted catalytic chemical vapor deposition (CCVD), the catalyst and carbon precursors are introduced simultaneously in the reactor. Catalyst particles are formed in situ and aligned multi-walled CNTs grow at a high rate. To scale-up the process, it is crucial to understand the chemical transformation of the precursors along the thermal gradient of the reactor, and to correlate nanotube growth with catalyst nanoparticle formation. The products synthesized along a cylindrical CVD reactor from an aerosol composed of ferrocene and toluene, as catalyst and carbon precursor, respectively, were studied. The product surface density and iron content are determined as a function of the location and the iron vapor pressure in the reactor. Samples are analyzed by electron microscopy, X-ray diffraction and Raman spectroscopy.We show the strong influence of the thermal gradient on location and rate of formation of both iron particles and CNTs, and demonstrate that catalyst particles are formed by gas phase homogeneous nucleation with a size which correlates with iron vapor pressure. They are gradually deposited on the reactor walls where nanotubes grow with an efficiency which is varying linearly with catalyst particle density. CNT crystallinity appears very high for a large range of temperature and iron content.
C. Castro, M. Pinault, S. Coste-Leconte, D. Porterat, N. Bendiab, C. Reynaud, M. Mayne-L’Hermite, Carbon 48 (2010) 3807-3816

A1954 – A comprehensive scenario for commonly used purification procedures of arc-discharge as-produced single-walled carbon nanotubes

The purification of single-walled carbon nanotube (SWCNT) samples was analysed using a multi-technique approach, with structural as well as spectroscopic probes, in order to characterize the samples and to identify important factors for improvement of SWCNT sample quality. The first dry oxidation step (air at 365 C) is shown to have only a weak selectivity for the removal of the amorphous carbon or weakly organized graphitic species as well as resulting in a partial consumption of the SWCNTs. The functionalization of the SWCNTs is highly specific with formation of carboxyl, hydroxyl and carbonyl groups. On the other hand this oxidation step is highly efficient for the oxidation of the catalytic impurities (Ni, Y) which can be easily removed by subsequent acid treatment. A final high temperature treatment indicates some incomplete restoration of the quality of the SWCNT surface.
Brigitte Vigolo, Claire Herold, Jean-François Marêche, Jaafar Ghanbaja, Michal Gulas, François Le Normand, Robert Almairac, Laurent Alvarez, Jean-Louis Bantignies, Carbon 48 (2010) 949-963

A1951 – Synthesis and characterisation of medium surface area silicon carbide nanotubes

Silicon carbide nanotubes with medium surface area (30–60 m /g) were successfully prepared by reaction between carbon nanotubes and SiO vapor according to the shape memory synthesis (SMS). The gross morphology of the carbon nanotubes was maintained during the carburization process. A calcination in air at 600 8C was performed to remove unreacted carbon domains in order to obtain pure carbon-free SiC nanotubes. The synthesized SiC nanotubes had a mean outer diameter of 100 nm and lengths up to several tens of micrometres
Nicolas Keller, Cuong Pham-Huu, Gabrielle Ehret, Valérie Keller, Marc J. Ledoux, Carbon 41 (2003) 2131–2139

A1946 – Processing and characterization of polyurethane nanocomposite foam reinforced with montmorillonite–carbon nanotube hybrids

This study investigates the effect of montmorillonite carbon nanotube hybrids on the final properties of polyurethane (PU) nanocomposite foams. The hybrids were fabricated by chemical vapour deposition and dispersed in rigid polyurethane foam by an in situ polymerization process. The resulting morphology and dispersion were evaluated by scanning electron microscopy, optical microscopy and transmission electron microscopy. PU nanocomposite foams have revealed the presence of cells of smaller size and an increase of cell density when compared to neat polymer foams. Thermogravimetric studies revealed that addition of the hybrids nanoparticles improve the thermal properties of the resulting nanocomposites. Addition of small amounts of montmorillonite carbon nanotube hybrids has enhanced the compressive properties of the resulting PU nanocomposite foams making it suitable for several applications.
Liliana Madaleno, Ryszard Pyrz, Alan Crosky, Lars R. Jensen, Jens Chr. M. Rauhe, Viktoriya Dolomanova, Ana Margarida Madeira Viegas de Barros Timmons, José Joaquim Cruz Pinto, Jennifer Norman, Composites: Part A 44 (2013) 1–7

A1945 – Durability of carbon nanofiber (CNF) & carbon nanotube (CNT) as catalyst support for Proton Exchange Membrane Fuel Cells

Durability issues have recently been given much attention in Proton Exchange Membrane Fuel Cell (PEMFC) research. It gives fundamental definition for cell life time, capital cost, system stability and technique reliability. Loss of catalyst surface area due to corrosion of supportingmaterial (normally carbon black) is one of the essential degradation mechanisms during cell operation. In this work, durability of carbon nanofibers (CNF) & carbon nanotubes (CNT) as alternative platinum catalyst supports for Proton Exchange Membrane Fuel Cells (PEMFCs) was assessed. Platinized CNF and CNT using a standard polyol method were prepared and fabricated as cathodes of Membrane Electrode Assemblies (MEA) for PEMFC. Both the catalysts as such and theMEAsmade out of them were evaluated regarding to thermal and electrochemical stabilities using traditional carbon black (Vulcan XC72) as a reference. Thermal gravimetric analysis (TGA), cyclic voltammetry (CV), polarization curve and impedance spectroscopy were applied on the samples under accelerated stress conditions. The carbon nano-materials demonstrated better stability as a support for nano-sized platinumcatalyst under PEMFC related operating conditions. Due to different morphology of the nano carbons compared to Vulcan XC 72 the electrode structures may still need optimization to improve the overall cell performance.
Shuang Ma Andersen, Maryam Borghei, Peter Lund, Yli-Rantala Elina, Antti Pasanen, Esko Kauppinen, Virginia Ruiz, Pertti Kauranen, Eivind M. Skou, Solid State Ionics 231 (2013) 94–101

A1944 – Comparison of structural properties of pristine and gamma irradiated single-wall carbon nanotubes: Effects of medium and irradiation dose

A systematic study of the gamma irradiation effects on single wall carbon nanotube (SWCNT) structure was conducted. Nanotubes were exposed to different doses of gamma irradiation in three media. Irradiation was carried out in air, water and aqueous ammonia. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and Raman spectroscopy confirmed the changes in the SWCNT structure. TGA measurements showed the highest percentage of introduced groups for the SWCNTs irradiated with 100 kGy. FTIR spectroscopy provided evidence for the attachment of hydroxyl, carboxyl and nitrile functional groups to the SWCNT sidewalls. Those groups were confirmed by EA. All irradiated SWCNTs had hydroxyl and carboxyl groups irrelevant to media used for irradiation, but nitrile functional groups were only identified in SWCNTs irradiated in aqueous ammonia. Raman spectroscopy indicated that the degree of disorder in the carbon nanotube structure correlates with the irradiation dose. For the nanotubes irradiated with the dose of 100 kGy, the Raman ID/IG ratio was three times higher than for the pristine ones. Atomic force microscopy showed a 50% decrease in nanotube length at a radiation dose of 100 kGy. Scanning and transmission electron microscopies showed significant changes in the morphology and structure of gamma irradiated SWCNTs
D. Kleut, S. Jovanovi?, Z. Markovi?, D. Kepi?, D. Toši?, N. Rom?evi?, M. Marinovi?-Cincovi?, M. Drami?anin, I. Holclajtner-Antunovi?, V. Pavlovi?, G. Draži?, M. Milosavljevi?, B. Todorovi? Markovi?,Materials Characterization 72 (2012) 37-45

A1943 – Influence of size and oxidative treatments of multi-walled carbon nanotubes on their electrocatalytic properties

The influence of chemical oxidation on the electrochemical behavior against hydrogen peroxide of long and short multi-walled carbon nanotubes (MWCNT) has been investigated. Different degrees of oxidation with a sulfo-nitric mixture and with nitric acid were used and a complete physical and oxygen functional group characterization was performed by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), acid group titration, transmission and scanning electron microscopies (TEM/SEM), elemental analysis, thermogravimetric analysis (TGA), nitrogen adsorption isotherms and cyclic voltammetry. The results revealed that electrodes modified using pristine short CNT (s-NC) present higher amperometric response against hydrogen peroxide than that obtained using long CNT (l-NC), which correlates with the greater degree of packing observed for l-NC by SEM and the long and thin structures observed in s-NC. On the other hand, the chemical oxidation process increases slightly the sensitivity of resulting electrodes, in about 25%, for both s-NC and l-NC indicating that for hydrogen peroxide oxidation the metal catalyst impurities, that are removed in the oxidation process, are not as relevant in the electrocatalysis as the increase in the capacitance values observed in the oxidized CNTs. The presence of oxygen groups introduces (a) new sites for redox reaction (pseudocapacitance) and (b) strong polar sites that would adsorb water molecules favoring double-layer formation (double-layer capacitance).
Paulina Canete-Rosales, Valeria Ortega, Alejandro Álvarez-Lueje, Soledad Bollo, Mónica González, Alejandro Ansón, María Teresa Martínez, Electrochimica Acta 62 (2012) 163–171

A1942 – Elimination of D-band in Raman spectra of double-wall carbon nanotubes by oxidation

In this Letter, we present an in situ Raman spectroscopy study of oxidation-induced changes in the structure and composition of double-wall carbon nanotubes (DWCNTs). Above 480 C, the intensity of the D band decreases to less than 0.01% of the G band intensity, when measured using the 780 nm laser excitation. The D band was absent from the Raman spectra recorded with the 514.5 nm excitation. Thermogravimetric analysis and high-resolution transmission electron microscopy are used to explain the observed results. We conclude that oxidation provides a purification method for the DWCNT which leads to a sample containing tubes having nearly clean surfaces without disordered carbon
S. Osswald, E. Flahaut, H. Ye, Y. Gogotsi, Chemical Physics Letters 402 (2005) 422–427

A1941 – Effect of chromium addition to the Co-MCM-41 catalyst in the synthesis of single wall carbon nanotubes

This paper studies the effect of chromium addition to the Co-MCM-41 catalyst in the synthesis of single wall carbon nanotubes (SWNT). The molecular ratios between the two metals have been varied in the catalyst template and their effect on the synthesized SWNT distribution has been studied. By adding Cr to the Co-MCM-41 monometallic catalyst, the diameter distribution of the synthesized SWNT has shifted towards smaller diameter tubes. This shift was correlated with the development of a bimetallic oxide in the MCM-41 framework during catalyst synthesis. By use of fluorescence spectroscopy, the relative abundance of certain tube chiralities has been seen to increase in the bimetallic samples compared to the monometallic ones as for example the (6,5) nanotube. X-ray absorption analysis of the catalyst before, during and after the SWNT synthesis, suggested that the use of a less reducible oxide (chromium oxide) to anchor clusters of a nanotube growth catalyst (cobalt clusters) is an important general tool for engineering the resultant nanotube properties. The addition of chromium has been seen to affect both the reducibility of the cobalt ions and the size of the resultant particles during the SWNT synthesis process.
Codruta Zoican Loebick, Salim Derrouiche, Fang Fang, Nan Li, Gary L. Haller, Lisa D. Pfefferle, Applied Catalysis A: General 368 (2009) 40–49

A1940 – Effect of reaction temperature in the selective synthesis of single wall carbon nanotubes (SWNT) on a bimetallic CoCr-MCM-41 catalyst

Synthesis of single wall carbon nanotubes (SWNT) on a CoCr-MCM-41 bimetallic catalyst by CO disproportionation has been carried out at five different temperatures between 500 and 900°C. A series of methods have been employed for a comprehensive assessment effect of temperature on the sizecontrollability of the catalyst particles and the morphology of the resultant SWNT. By extended fine structure X-ray absorption, thermogravimetric analysis, resonance Raman spectroscopy, photoluminescence excitation (PLE) mapping and transmission electronmicroscopy we found an optimal synthesis temperature window between 600 and 800 8C. In this window, modifying the reaction temperature leads to significant changes in the SWNT yield, diameter and chirality distribution. Decrease in reaction temperature favored the selective synthesis of very small diameter carbon nanotubes (as lowas 0.6 nm). Chirality dependence of SWNT on temperature has been measured by PLE. A progressive suppression of larger diameter SWNT identities in the measured SWNT population was noted when reaction temperature decreased. In the measured PL maps, two near armchair structures (6,5) and (7,3) were dominant at 600 and 700 8C.
Codruta Zoican Loebick, Darlington Abanulo, Magda Majewska, Gary L. Haller, Lisa D. Pfefferle, Applied Catalysis A: General 374 (2010) 213–220

A1939 – Thermogravimetric studies of carbon nanofiber formation from methane at low temperature over Ni-based skeletal catalysts and the effect of substrate pre-carburization

Using thermogravimetry (TG) under conditions that minimize inhibition by the hydrogen produced, the intrinsic catalytic rates of skeletal Ni, pure and alloyed with solute metals Fe, Co, or Cu, were evaluated in methane decomposition to carbon nanofibers. In ‘‘standard’’ tests, i.e., after pre-reduction in H2 and exposure to CH4 directly at 450 C, several catalysts reached stable activities exceeding 4 mg C/mg cat./h, comparable with literature values obtained at 500 C or above. TG evidence is presented for partial bulk carburization of Ni in CH4 below 350 C, which leads to substantially increased coking rates. TEM evidence supports the view that carburization promotes catalyst particle disintegration, thereby inducing faster and more stable nanofiber growth. Irregularities in alloy response to carburization are interpreted in terms of the stability of the respective mixed-metal carbides. TEM also shows that alloying changes the metal nanocrystallite shape (habit), with consequences for the carbon nanofiber structure. Evidence for the easy dissociation of CH4 is corroborated by direct catalyst activation in the absence of H2. Reduction begins in pure hydrocarbon around 300 C and leads to coking activities at 450 C comparable to those for samples pre-reduced in H2. Skeletal metal catalysts offer distinct advantages in low-temperature natural gas conversion.
James Highfield, Yook Si Loo, Ziyi Zhong, Benjamin Grushko, Carbon 45 (2007) 2597–2607

A1932 – The effect of the functionalization of carbon nanofibers on their electronic conductivity

The effects of the functionalization of carbon nanofibers (CNFs) on their electronic conductivity, in addition to their physico-chemical properties have been studied. Oxygen surface groups have been created on the surface of three CNFs with different properties, following three oxidation treatments with diverse severity. The oxygen content increased from two to six times the original content, depending on the CNF texture, from 1.5–2.6 wt.% up to 15.1 wt.%. Whereas some important properties are not significantly modified after functionalization (texture, crystalline structure, etc.), other properties like the electronic conductivity are affected depending on the extent of the process. The electronic conductivity of CNFs decreases from 200–350 Sm 1 up to 20–100 S m 1 (the precise value depends on carbon crystallinity and compaction degree) when surface oxygen content increases from 1.5 wt.% to 5 wt.%. A further oxidation degree leads to a 90% decrease in conductivity, and in the end can even destroy the original fibrous structure. As a first approach, oxidizing at room temperature with rather strong acid solutions is a better strategy to create functional groups and maintain the electronic conductivity than increasing the process temperature with less severe oxidizing agents.
D. Sebastian, I. Suelves, R. Moliner, M.J. Lazaro, 48 (2010) 4421-4431

A1913 – Study of thermal stabilization for polystyrene/carbon nanocomposites via TG/DSC techniques

The degradability and durability for polymer–nanocomposites under various environmental conditions are from the essential fields of research. This study was carried out to examine the thermal stability of polystyrene loaded by carbon (C) nanoparticles up to 20 wt% content. The thermal degradation of PS/C nanocomposites were studied by thermogravimetry analysis and differential scanning calorimetry (DSC) under non-isothermal condition and inert gas atmosphere at constant heating rate 10 °C min-1. The variation of degradation characteristic temperatures as a function of C content has been a non-monotonic behavior. The obtained results suggested that the C nanoparticles act as a promoter slowing down the degradation and providing a protective barrier to the nanocomposite, except 5 wt% C content. The latter exception was confirmed by DSC curve through the emergence of a small endothermic peak before the fundamental endothermic, melting, one.
Sh. A. Mansour, J Therm Anal Calorim, 2012

A1865 – Synthesis, characterization and thermal analysis of urea–formaldehyde/nanoSiO2 resins

In the present work urea–formaldehyde resins (UF) containing different amounts of SiO2 nanoparticles were synthesized and studied in depth. All the hybrids were characterized with Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffractometry (XRD), while the dispersion of nanoparticles was studied with scanning electron microscopy with associated energy dispersive X-ray spectrometer (SEM/EDS). It was found that even though silanol groups of SiO2 can interact with UF resin and form hydrogen bonds, aggregates of SiO2 nanoparticles can still be formed in UF resin. Their size increases as SiO2 content is increased. The curing reactions were examined with differential scanning calorimetry (DSC) and it was revealed that curing temperature of UF resin is slightly affected by the addition of nanoparticles. Furthermore, the activation energy of the curing reactions, for every hybrid, was calculated using the Kissinger’s method, which implied the existence of interactions between the nanoparticles and the polymer chain. Thermogravimetric analysis (TGA) revealed that SiO2 nanoparticles do not have an effect in the thermal stability of the resin. From the application of the prepared UF/SiO2 resins in wood panels it was found that the mechanical properties of the panels, like the internal bond and the modulus of rapture, are enhanced with increasing nanoSiO2 concentration.
E. Roumelia, E. Papadopouloub, E. Pavlidoua, G. Vourliasa, D. Bikiaris c, K.M. Paraskevopoulosa, K. Chrissafis, Thermochimica Acta 527 (2012) 33– 39

A1857 – An optimal low-temperature tartrate precursor method for the synthesis of monophasic nanosized ZnFe2O4

In this study, the synthesis of monophasic nanocrystalline zinc ferrite (ZnFe2O4) was achieved by controlling the thermal decomposition conditions of a zinc–iron tartrate precursor method. Differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), Fe2+ content analysis, transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) techniques were used to investigate the effect of heat treatment conditions on the calcined powders. The thermal decomposition of the precursor led to an intermediate phase formation of ZnO, Fe3O4, and ?-Fe2O3. It was found that the Fe3O4 ? ?-Fe2O3 oxidation reaction is the key step in producing monophasic nanosized ZnFe2O4. The monophasic nanoparticles of ZnFe2O4 can be obtained when the precursor is heat treated under a low temperature (300–400 °C) and long residence time (4 h) process that can prompt the Fe3O4 oxidation and prevent the formation of ?-Fe2O3.
J. M. Yang, K. L. Yang, J Nanopart Res (2009) 11, 1739–1750

A1845 – The role of synthetic parameters in the magnetic behavior of relative large hcp Ni nanoparticles

The controllable synthesis of relatively large nickel nanoparticles via thermal decomposition of nickel acetate tetrahydrate in oleylamine in the presence of 1-adamantane carboxylic acid (ACA) and trioctylphosphine oxide (TOPO) is reported. High crystalline hcp nanoparticles of different sizes have been prepared at 290 °C, whereas at relative lower temperatures fcc are favored. The particle size was varying between 50 and 150 nm by properly adjusting the proportion of the capping ligands. TOPO-to-ACA ratio was also found to have an influence on the magnetic properties through the potential formation of a NiO shell. Pure hcp Ni nanoparticles over 50 nm in size served as models to illuminate the magnetic behavior of this metastable hexagonal Ni phase. Contrary to the net ferromagnetic characteristics of fcc Ni nanoparticles in the same size range, hexagonal structured particles exhibit superparamagnetic behavior at room temperature and a weak ferromagnetic contribution below 15 K.
A. Kotoulas, M. Gjoka, K. Simeonidis, I. Tsiaoussis, M. Angelakeris, O. Kalogirou, C. Dendrinou-Samara, J Nanopart Res (2011) 13, 1897–1908

A1755 – Sucrose assisted hydrothermal synthesis of SnO2/graphene nanocomposites with improved lithium storage properties

SnO2/graphene nanocomposites are synthesized by a new hydrothermal treatment strategy under the assistance of sucrose. From the images of the scanning electron microscope (SEM) and transmission electron microscope (TEM), it can be observed that SnO2 nanoparticles with the size of 4~5 nm uniformly distribute on the graphene nanosheets. The result demonstrates that sucrose can effectively prevent graphene nanosheets from restacking during hydrothermal treatment and subsequently treatment. The charging/discharging test result indicates that the SnO2/graphene nanocomposites exhibit high specific capacity and excellent cycleability. The first reversible specific capacity is 729 mAh.g?1 at the current density of 50 mA.g?1, and remains 646 mAh.g?1 after 30 cycles at the current density of 100 mA.g?1, 30 cycles at the current density of 200 mA.g?1, 30 cycles at the current density of 400mA.g?1, 30 cycles at the current density of 800 mA.g?1, and 30 cycles at the current density of 50 mA.g?1.
Xiao-Yong Fan, Xiao-Yuan Shi, Jing Wang, Yong-Xin Shi, Jing-Jing Wang, Lei Xu, Lei Gou, Dong-Lin Li, J Solid State Electrochem, 2012

A1723 – Synthesis of amorphous acid iron phosphate nanoparticles

A simple method to precipitate nanoparticles of iron phosphate with acid character has been developed in which the control of pH allows to obtain amorphous nanoparticles. The acid aging of the precipitated amorphous nanoparticles favored the P–O bond strength that contributes to the surface reordering, the surface roughness and the increase of the phosphate acid character. The thermal behavior of the acid iron phosphate nanoparticles has been also studied and the phosphate polymerization at 400 °C produces strong compacts of amorphous nanoparticles with interconnected porosity.
E. Palacios, P. Leret, J. F. Fernandez, A. H. De Aza, M. A. Rodr?guez, J Nanopart Res (2012) 14, 1131

A1720 – Control of the Properties of Carbon Nanotubes Synthesized by CVD for Application in Electrochemical Biosensors

Interest in carbon nanotubes (CNT) has grown at a very rapid rate in the last decade. Their interesting physical and chemical properties open attractive possibilities in many application areas. These properties depend on the process conditions during synthesis and on subsequent purification steps. Recent studies have demonstrated that CNT can promote the electron transfer of biomolecules. These exceptional properties make them attractive for use in electrochemical biosensors. Multi walled nanotubes have been synthesized by the Chemical Vapor Deposition (CVD) method using methane as a carbon source and Ni–Al2O3–SiO2 as the catalyst. The influence of the variation of certain reaction parameters such as feed gas composition, catalyst mass, temperature and reaction time in the yield of the CVD process has been established. In addition, the structural and chemical characteristics of the CNTs have been studied and a purification process to eliminate the catalyst and amorphous carbon has been developed that involves a gaseous oxidative process and acid treatment. The efficiency of the purification step has been determined by analytical techniques, including thermogravimetric analysis.
Izaskun Bustero , Garc?a Ainara, Obieta Isabel, Munoz Roberto, Rincon Ines, Arteche Amaya, Microchim Acta 152, 239–247 (2006)

A1692 – Enhancing mechanical and thermal properties of PLLA ligaments with fumed silica nanoparticles and montmorillonite

Nanocomposites of poly(L-lactic acid) (PLLA) containing 2.5 wt% of fumed silica nanoparticles (SiO2) and organically modified montmorillonite (OMMT) were prepared by solved evaporation method. From SEM micrographs it was observed that both nanoparticles were well dispersed into PLLA matrix. All nanocomposites exhibited higher mechanical properties compared to neat PLLA, except elongation at break, indicating that nanoparticles can act as efficient reinforcing agents. Nanoparticles affect, also, the thermal properties of PLLA and especially the crystallization rate, which in all nanocomposites is faster than that of neat PLLA. From the thermogravimetric curves it can be seen that neat PLLA nanocomposites present a relatively better thermostability than PLLA, and this was also verified from the calculation of activation energy (E). From the variation of E with increasing degree of conversion it was found that PLLA/ nanocomposites decomposition takes place with a complex reaction mechanism, with the participation of two different mechanisms. The combination of models, nth order and nth order with autocatalysis (Fn–Cn), for PLLA and PLLA/OMMT as well as the combination of Fn–Fn for PLLA/SiO2 give the better results. For the PLLA/OMMT the values of the E for both mechanisms are higher than neat PLLA. For the PLLA/SiO2 nanocomposite the value of the E is higher than the corresponding value for PLLA, for the first area of mass loss, while the E of the second mechanism has a lower value
K. Chrissafis, E. Pavlidou, K. M. Paraskevopoulos, T. Beslikas, N. Nianias, D. Bikiaris, J Therm Anal Calorim (2011) 105, 313–323

A1690 – Effect of acid treated multi-walled carbon nanotubes on the mechanical, permeability, thermal properties and thermo-oxidative stability of isotactic polypropylene

The effect of acid treatment of multi-walled carbon nanotubes (MWCNTs) on the mechanical, thermal and mainly thermo-oxidative stability of isotactic polypropylene (iPP) was evaluated. From the acid treatment surface carboxylic groups were mainly formed, while the nanotubes’ length was gradually reduced by increasing the treatment time. Young’s modulus, tensile strength and storage modulus of the iPP/MWCNT nanocomposites were increased by increasing the treatment time of the MWCNTs, due to finer dispersion inside the polymer matrix, as revealed by TEM and micro-Raman spectroscopy. Furthermore, the nanotubes acted as nucleating agents, an effect more pronounced with finer filler dispersion. Thermal stability in an inert atmosphere also increased. Thermo-oxidative stability tests in air and O2 revealed that oxidative degradation took place in two stages. In the first stage, corresponding to temperatures up to 230 C, the MWCNTs accelerated the oxidation of iPP, while at higher than 300 C temperatures the trend was reversed. Incubation studies proved that, at the first stages, oxidation was due to random chain scission of iPP and oxygen uptake. This behaviour was accelerated by the MWCNTs’ surface carboxylic groups and, as found by O2 permeability studies, was mainly a surface process. In the second stage, due to the shielding effect of MWCNTs, the removal of the gases produced during decomposition was hindered. At this stage the presence of MWCNTs resulted in more thermo-oxidatively stable nanocomposites.
D. Bikiaris, A. Vassiliou, K. Chrissafis, K.M. Paraskevopoulos, A. Jannakoudakis, A. Docoslis, Polymer Degradation and Stability 93 (2008) 952e967

A1685 – Oxidized Multiwalled Carbon Nanotubes as Effective Reinforcement and Thermal Stability Agents of Poly(lactic acid) Ligaments

In this study, nanocomposites of poly(lactic acid) (PLA) containing 0.5, 1, and 2.5 wt % oxidized multiwalled carbon nanotubes (MWCNT–COOHs) were prepared by the solved evaporation method. From transmission electron microscopy and scanning electron microscopy micrographs, we observed that the MWCNT–COOHs were well dispersed in the PLA matrix and, additionally, there was increased adhesion between PLA and the nanotubes. As a result, all of the studied nanocomposites exhibited higher mechanical properties than neat PLA; this indicated that the MWCNT–COOHs acted as efficient reinforcing agents, whereas in the nonoxidized multiwalled carbon nanotubes, the mechanical properties were reduced. Nanotubes can act as nucleating agents and, thereby, affect the thermal properties of PLA and, especially, the crystallization rate, which is faster than that of neat PLA. From the thermogravimetric data, we observed that the PLA/MWCNT–COOH nanocomposites presented relatively better thermostability than PLA; this was also verified from the calculation of activation energy. On the contrary, the addition of MWCNT–COOH had a negative effect on the enzymatic hydrolysis rate of PLA
K. Chrissafis, K. M. Paraskevopoulos, A. Jannakoudakis, T. Beslikas, D. Bikiaris, Journal of Applied Polymer Science,Vol. 118, 2712–2721 (2010)

A1684 – Nanocomposites of isotactic polypropylene with carbon nanoparticles exhibiting enhanced stiffness, thermal stability and gas barrier properties

Carbon nanoparticles (CN), synthesized by a shock wave propagation method from the free carbon of the explosive, were dispersed in isotactic polypropylene (iPP) using a twin screw co-rotating extruder. These materials were analyzed for their tensile properties, crystallization morphology, thermal stability under N2, O2 and air, as well as their permeability rates for N2, O2 and CO2. Young’s modulus was significantly enhanced, as was the tensile strength at the yield point, although at a smaller extent. However, the tensile strength and elongation at the break point slightly deteriorated with the increase of the Filler’s concentration. This behaviour was attributed to the increase tendency of CN to form aggregates into iPP matrix by increasing its content. The size of aggregates, as was evaluated by extended micro-Raman mapping, is ranged from 1 up to 5 lm. The nanoparticles caused a significant reduction of the iPP chain’s mobility leading to smaller and less ordered crystallites, with the appearance of c-phase crystallites at CN content 5 wt.%. In inert atmosphere (N2) the presence of the nanoparticles caused a shift of the starting decomposition temperature (Td), from 368 up to 418.6 C, while, under oxygen, thermal decomposition was more complex, displaying more than two stages. The Td was slightly lowered, up to a filler content of 2.5 wt.%, with the nanoparticles exhibiting a catalytic role at the beginning of the polymer’s decomposition. Under air, the degradation behaviour was between those exhibited in inert and O2 atmospheres. Permeability rates for the gases measured were substantially lowered with increasing filler content.
A. Vassiliou, D. Bikiaris, K. Chrissafis, K.M. Paraskevopoulos, S.Y. Stavrev, A. Docoslis, Composites Science and Technology 68 (2008) 933–943

A1683 – Comparative Study of the Effect of Different Nanoparticles on the Mechanical Properties, Permeability, and Thermal Degradation Mechanism of HDPE

In the present study, different series of high-density polyethylene (HDPE) nanocomposites were prepared by melt mixing on a Haake-Buchler Reomixer, containing 2.5 wt % of multiwall carbon nanotubes, pristine and modified montmorillonite, surface-treated and -untreated SiO2 nanoparticles. From transmission electron micrographs, it was found that beyond a fine dispersion of nanoparticles into HDPE matrix, there are also some aggregates easily discriminated. As a result, there was a decrease in the tensile and impact strength of most of nanocomposites except Young’s modulus, which was increased. Storage modulus as recorded from dynamic mechanical analysis was also increased in all nanocomposites, because HDPE becomes stiffer due to the incorporation of nanoparticles. The nucleation behavior of nanoparticles during crystallization was found to have no obvious effect on melting and crystallization temperature of HDPE. However, a small decrease in the heat of fusion in all nanocomposites was evidenced. Gas permeability of HDPE matrix in O2, N2, and CO2 was reduced in all nanocomposites compared with neat polymer. Thermal stability of HDPE was also enhanced due to the incorporation of different nanoparticles. From the kinetic analysis of thermal decomposition of HDPE, it was concluded that to describe the thermal degradation of HDPE and the studied nanocomposites, two consecutive mechanisms of nth-order autocatalysis have to be considered.
K. Chrissafis, K. M. Paraskevopoulos, I. Tsiaoussis, D. Bikiaris, Journal ofAppliedPolymer Science,Vol. 114, 1606–1618 (2009)

A1681 – Thermal and Dynamic Mechanical Behavior of Bionanocomposites: Fumed Silica Nanoparticles Dispersed in Poly(vinyl pyrrolidone), Chitosan, and Poly(vinyl alcohol)

Various bionanocomposites were prepared by dispersing fumed silica (SiO2) nanoparticles in biocompatible polymers like poly(vinyl pyrrolidone) (PVP), chitosan (Chi), or poly(vinyl alcohol) (PVA). For the bionanocomposites preparation, a solvent evaporation method was followed. SEM micrographs verified fine dispersion of silica nanoparticles in all used polymer matrices of composites with low silica content. Sufficient interactions between the functional groups of the polymers and the surface hydroxyl groups of SiO2 were revealed by FTIR measurements. These interactions favored fine dispersion of silica. Mechanical properties such as tensile strength and Young’s modulus substantially increased with increasing the silica content in the bionanocomposites. Thermogravimetric analysis (TGA) showed that the polymer matrices were stabilized against thermal decomposition with the addition of fumed silica due to shielding effect, because for all bionanocomposites the temperature, corresponding to the maximum decomposition rate, progressively shifted to higher values with increasing the silica content.
Konstantinos Chrissafis, Konstantinos M. Paraskevopoulos, George Z. Papageorgiou, Dimitrios N. Bikiaris, Journal of AppliedPolymer Science,Vol. 110, 1739–1749 (2008)

A1675 – Reduction Kinetics of FeO-CoO Solid Solution by Hydrogen Gas

The reduction kinetics of the FeO-CoO solid solutions (Fe0.8Co0.2O, Fe0.7Co0.3O, and Fe0.6Co0.4O) by hydrogen gas has been investigated using the thermogravimetric technique. Isothermal experiments were carried out in the temperature range 573 to 973 K. The activation energies for the reduction were calculated from the results of the isothermal experiments, and a typical value for Fe0.8Co0.2O solid solution was 65.9 kJ/mol. The activation energy values were found to be higher than the corresponding values for FeO and CoO obtained earlier under identical reduction conditions. Fine Fe-Co alloy particles were obtained by carrying out the reduction experiments using a fluidized bed reactor with the parameters defined by the ther- mogravimetric results. The transmission electron microscope and laser particle sizer studies confirmed that the particle size of the synthesized alloys is in the range of 20 to 300 nm. By using vibrating sample magnetomer measurements, the saturation magnetization values (Ms) were evaluated to be 196 emu/g and the coercive field was 33 Oe for Fe0.8Co0.2
Lidong Teng, Satoko Noguchi, Seshadri Seetharaman, Metallurgical and Materials Transactions B, Vol. 38B, 55, Février 2007

A1655 – Blue TiO(2-x)/SiO2 nanoparticles by laser pyrolysis

Composite TiSiOC nanoparticles with Ti/Si ratio varying in a very large range were prepared by laser pyrolysis of a gas–spray mixture of silane and titanium tetra-isopropoxide. The as-formed nanoparticle batches exhibit intense blue colours, varying from dark to light blue while the Ti/Si ratio increases. This blue colour is attributed to the formation of sub-stoichiometric TiO(2-x) compounds induced by the presence of reducing agents such as silicon-based radicals and carbon atoms in the reaction medium. The blue colour of the powders is stable for several months at room temperature in normal atmospheric conditions. Elemental analysis, specific surface area and pycnometry measurements, as well as Photon Correlation Spectroscopy allow determining the chemical composition and size of the as-synthesized nanoparticles as a function of the Ti/Si ratio. X-ray diffraction, transmission electron microscopy and IR spectroscopy have been used to analyse their chemical organisation, nanostructure and morphology. Mean grain size is found around 20 nm. The nanoparticles exhibit a core-shell structure TiO(2-x)/SiO2, with a core made of titania, surrounded by an amorphous shell, mainly of silica. Crystallites of anatase are present in the core with size increasing with the Ti/Si ratio. Annealing under air at 800°C induces the removal of carbon and the crystallisation of the powders with light beige to white colours.
Hicham Maskrot, Nathalie Herlin-Boime, Yann Leconte, Krystina Jursikova, Cécile Reynaud, Jean Vicens, Journal of Nanoparticle Research (2006) 8: 351–360

A1643 – Metallic Particles from Complexing Microcapsules Dispersed in a Silica Gel

A new process to control the distribution of metal nanoparticles is proposed. It involves the use of complexing microcapsules obtained by interfacial polycondensation. The latter are hollow spheres constituted of a polymer membrane, containing an insoluble active ingredient, such as a polyacrylic acid, which can complex Co2+ ions. These capsules are dispersed in a silica sol followed by thermal treatments and reduction under H2 which results in metallic Co nanoparticles confined in the capsules domains. The particles do not diffuse in the matrix.
Mireille Richard-Plouet, Jean-Louis Guille, Yves Frere, Louis Danicher, Journal of Sol-Gel Science and Technology 25, 207–213, 2002

A1634 – Large influence of the synthesis conditions on the physico-chemical properties of nanostructured Fe3O4

Magnetite synthesized via three different synthesis routes (coprecipitation process in aqueous media, electrochemical synthesis in presence of complexing agents and solid state reaction at high temperature) has been characterized by X-Ray diffraction, scanning electron microscopy, thermal analysis (TGA), FT-IR and Mössbauer spectroscopies. Although each procedure gave homogeneous magnetite powders, many differences could be seen in the physico-chemical properties of the samples mostly depending on the synthesis conditions. For instance, at least two factors seem to have a huge impact onto the Fe3O4 behaviour: the presence of hydration water molecules and the particle size of the powders since a super-paramagnetic behaviour was observed with the thinnest particles, at room temperature, on the Mössbauer spectra via the appearance of line broadening and a pronounced central doublet.
S. Franger, P. Berthet, O. Dragos, R. Baddour-Hadjean, P. Bonville, J. Berthon

A1633 – Electrochemical synthesis of Fe3O4 nanoparticles in alkaline aqueous solutions containing complexing agents

Ultrafine magnetite particles are prepared through an electrochemical process, at room temperature, from an iron-based electrode immersed in an alkaline aqueous medium containing complexing compounds. XRD and chemical analysis indicate that the product is pure magnetite, Fe3O4. The size and morphology of the particles are studied by SEM. The magnetite nanoparticles present a magnetoresistance of almost 3%, at 300 K, under a magnetic field of 1 T. A reactive mechanism for the electrochemical process is proposed.
S. Franger, P. Berthet, J. Berthon, J Solid State Eletrochem (2004) 8, 218–223

A1622 – Uniform nanoparticles building Ce12xPrxO22d mesoarchitectures: structure, morphology, surface chemistry, and catalytic performance

Ce1-xPrxO2-d (x = 0, 0.1, 0.5, 0.9) mesoarchitectures built from nanoparticles with crystalline framework have been synthesized by the self-assembly method assisted by surfactants and hydrothermal treatment. Cetyltrimethylammonium bromide (CTAB) was used as template, urea as hydrolyzing agent and tetraethylammonium hydroxide (TEAOH) as pH mediator to obtain pH 9. The inorganic precursors have been co-assembled with surfactant template to produce mesoarchitectures which have uniform pore size distribution, crystalline channel walls, high thermal stability, and high catalytic activity in the oxidation reaction of methane. The resulting powders, calcined at 550 °C, were characterized by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption/desorption isotherms (BET), thermogravimetric analysis (TG-DTG), scanning and transmission electron microscopy (SEM, TEM, and HRTEM), and X-ray photoelectron spectroscopy (XPS).
Simona Somacescu, Viorica Parvulescu, Jose Maria Calderon-Moreno, Soong-Hyuck Suh, Petre Osiceanu, Bao-Lian Su, J Nanopart Res (2012) 14, 885

A1620 – Facile preparation of single-crystalline nanowires of ?-MnOOH and ?-MnO2

A facile method has been developed to synthesize single-crystalline manganese (oxyhydr)oxide nanowires. A pure phase of single-crystalline ?-MnOOH nanowires with the lengths of several hundred nanometres to several micrometers and the diameters of 5–40 nm was synthesized by hydrothermal transformation of commercial granular ?- or ?-MnO2 in water, and single-crystalline ?-MnO2 and polycrystalline ?-Mn2O3 nanowires formed after subsequent calcination at 300 and 600 ?C of the as-prepared ?-MnOOH nanostructures, respectively. These low-dimensional nanostructured materials may find novel properties and provide more possible applications in lithium batteries and catalysis.
Z.-Y. Yuan, T.-Z. Ren, G.-H. Du, B.-I. Su, Appl. Phys. A 80, 743–747 (2005)

A1596 – Targeted Herceptin–dextran iron oxide nanoparticles for noninvasive imaging of HER2/neu receptors using MRI

A novel magnetic resonance imaging (MRI) contrast agent containing Herceptin is reported. The surfaces of superparamagnetic iron oxide nanoparticles were modified with dextran and conjugated with Herceptin (Herceptin–nanoparticles) to improve their dispersion, magnetization, and targeting of the specific receptors on cells. From analytical results, we found that Herceptin–nanoparticles were well dispersed in solutions of various pH range, and had no hysteresis, high saturation magnetization (80 emu/g), and low cytotoxicity to a variety of cells. Notably, the magnetic resonance enhancements for the different breast cancer cell lines (BT-474, SKBR-3, MDA-MB-231, and MCF-7) are proportional to the HER2/neu expression level in vitro. When Herceptin–nanoparticles were administered to mice bearing breast tumor allograft by intravenous injection, the tumor site was detected in T2-weighted magnetic resonance images as a 45% enhancement drop, indicating a high level of accumulation of the contrast agent within the tumor sites. Therefore, targeting of cancer cells was observed by in vitro and in vivo MRI studies using Herceptin–nanoparticles contrast agent. In addition, Herceptin–nanoparticles enhancing the magnetic resonance signal intensity were sufficient to detect the cell lines with a low level of HER2/neu expression.
Ting-Jung Chen, Tsan-Hwang Cheng, Chiao-Yun Chen, Sodio C. N. Hsu, Tian-Lu Cheng, Gin-Chung Liu, Yun-Ming Wang, J Biol Inorg Chem (2009) 14, 253–260

A1577 – Photocatalytic activity of nanocrystalline TiO2 (brookite, rutile and brookite-based) powders prepared by thermohydrolysis of TiCl4 in aqueous chloride solutions

Nanocrystalline TiO2 powders were synthesized by thermohydrolysis of TiCl4 in HCl or NaCl aqueous solutions. Rutile, mixtures of brookite and rutile or mixtures of anatase, brookite and rutile were obtained depending on the acidity of the medium. Crystalline phases and composition of the mixtures were identified by using XRD analysis. Pure brookite nanoparticles, separated from the mixtures of brookite and rutile by simple peptization with water, were stable against transformation to rutile up to 750 ?C. The prepared TiO2 powders were characterized by thermal analysis, diffuse reflectance spectroscopy and BET surface area determinations. The band gap of bulky brookite was estimated 3.29 eV. 4-Nitrophenol photodegradation was used to evaluate the photocatalytic activity of the various samples. The highest activity corresponded to the powders consisting of more than one crystalline phase.
Agatino Di Paola, Giovanni Cufalo, Maurizio Addamo, Marianna Bellardita, Renzo Campostrini, Marco Ischia, Riccardo Ceccato, Leonardo Palmisano, Colloids and Surfaces A: Physicochem. Eng. Aspects 317 (2008) 366–376

A1576 – Mechanical and thermal properties of a nanopowder talc compound produced by controlled ball milling

A powdered compound constituted by over the 95% of talc Mg3Si4O10(OH)2 with MgCO3 and CaMg(CO3)2 as minor phases was mechanically deformed by compaction and shear to a nanosized particulate (crystallite size *5 nm) in a specifically built planetary ball mill. The mechanical milling was conducted in a controlled thermodynamic environment (25 °C and 0.13 Pa) by using low mechanical load to minimise amorphisation of the material. Mechanical s(e) shear analysis and thermo-structural modifications of the nanostructured talc particulate were investigated after selected milling times (0, 1, 5 and 20 h). At the very early stages of milling (1 h) layer flattening, lamination and texturing of the talc particles occurred. For prolonged milling (up to 20 h), a progressive reduction of the TOT talc stacking layer coherence, from about 20–5 nm, and an increase of (001) microstrain from about 0.6–2.2 9 10-2 nm, as a non-linear function of the treatment time, were observed. A progressive increase of the specific surface area up to 28 m2/g as a consequence of the particle size reduction took place at intermediate milling times (5 h) and reduced to about 10 m2/g at prolonged milling (20 h). Even the thermo-structural behaviour of the particulate was significantly modified. For 20-h milled talc, a severe decrease of the dehydroxylation temperature from about 900–600 °C was observed with a concomitant anticipation of the recrystallisation of talc into MgSiO3 (enstatite). The s(e) behaviour of the compound was strongly affected by the milling treatment changing from a shear-softening regime (untreated and 1 h) to a shear-hardening one (20 h). The observed changes of talc are of great importance to understand the rheology and the thermal transformation kinetics of talc compounds and can be exploited in those industrial applications that required milling of talc, such as in the production of talc-polymers nanocomposites or in medium–high-temperature ceramic processes.
Francesco Dellisanti, Vanna Minguzzi, Giovanni Valdre, J Nanopart Res (2011) 13, 5919–5926

A1565 – Nanosized SrTiO3 powder from oxalate precursor microwave aided synthesis and thermal characterization

Nanosized strontium titanate (SrTiO3) was synthesized from strontium titanyl oxalate hydrate, SrTiO(C204)2 4H20 (STO) precursor employing microwave heating technique. STO precursor was characterized by Thermogravimetry (TG) and differential thermal analysis (DTA) techniques prior to the heat treatment in conventional and microwave heating system. STO precursor heated in microwave heating system in air at 773 K for 30 min yielded pure cubic SrTiO3. The product obtained by heating of STO precursor in the same system at 973 K for same duration was, however, much more crystalline. Experiments repeated in conventional furnace showed that SrTiO3 was formed above 973 K. SrTiO3 powder obtained was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM) techniques. TEM study shows that the particles of SrTiO3 are nearly spherical in shape and the particle size of SrTiO3 powder varies between 28 and 68 nm.
Y. S. Malghe, J Therm Anal Calorim (2010) 102:831–836

A1533 – Elaboration of nanostructured Eu3+-doped Gd2O3 phosphor fine spherical powders using polyol-mediated synthesis

Red-emitting Eu3+-doped Gd2O3 spherical powders were directly precipitated using a polyol method. The as-synthesized powders consist of agglomerates with a spherical shape and a size ranging between 0.4 and 0.6 ?m. Each agglomerate is nanostructured and consists of a packing of nanocrystallites (3–5 nm) of a bcc oxide phase whose luminescence presents original features in comparison with bulk materials. The powders were further calcinated and the size of both crystallites and agglomerates, the crystalline structure and the luminescence were studied as a function of the annealing temperature. For temperatures lower than 900 ?C, the samples obtained are highly crystalline and possess the classical Eu3+ red luminescence. For optimized temperature, the morphology of the particles can be preserved leading to spherical, dense, luminescent and almost monodisperse oxide powders, 0.5 ?m in size.
M.A.Flores-Gonzalez, C. Louis, R. Bazzi, G. Ledoux, K. Lebbou, S. Roux, P. Perriat, O. Tillement, Appl. Phys. A 81, 1385–1391 (2005)

A1532 – Deposit of UV- or !-synthesized gold nanoparticles on TiO2 powder using lipid-based multilamellar vesicles

This article describes a general method for the deposition of gold nanoparticles onto solid support based on the use of multilamellar vesicles (MLVs). Gold nanoparticles (nps) synthesized within lipid-based MLVs by UV-or ?-irradiation were deposited onto TiO2 powder support. The organic phase from MLVs was removed by calcination leading to high dispersion of naked Au nanoparticles. The resulting particles were investigated using spectrometry, electron microscopy and XPS. The gold nanoparticles were stable and well-separated on the titania surface. It was found that the metal nanoparticles produced by radiolysis have smaller average size and narrower size distribution than those synthesized by photochemical route. After calcinations, the particles tended to enlarge to reach c.a. 18 nm. The gold loading on the titania support could be controlled by changing the gold salt concentration and the MLV-to-TiO2 weight ratio; values of Au-to-Ti ratio up to 44 % could be obtained.
Adeline Lafon, Mona Tréguer-Delapierre, Damien Bazin, Chrystel Faure, Colloid Polym Sci (2012) 290, 1015–1022

A1494 – About MX3 and MX2 (Mn+ = Mg2+, Al3+, Ti4+, Fe3+; Xp? = F?, O2?, OH?) nanofluorides

Several nanosized fluoro-compounds have been prepared by microwave-assisted solvothermal routes: Al3+-, Fe3+- and Ti4+-based oxyfluorides with the hexagonal tungsten bronze (HTB) framework, Ti4+-based fluorinated anatase, and rutile MgF2. The structural features have been determined using XRD and TEM analyses. The presence of OH? groups substituted for F? ions has been demonstrated for all of these nanofluorides. In Al- and Mg-based nanofluorides, the OH rate can be reduced by F2-direct fluorination. Furthermore, the higher the polarizing power of the cation, the higher the oxygen content. For cation with high formal charge, such as Ti4+ stabilized in a distorted octahedral site, the occurrence of O2?/OH?/F? anions in its vicinity as well as vacancies have to be mentioned. Finally coupling the microwave-assisted solvothermal route with the F2-direct fluorination allow preparing high surface area metal fluorides where the amount of oxygen is noticeable and contribute to create under-coordinated cationic species at the surface which can induce high Lewis acidity.
A. Demourgues, N. Penin, D. Dambournet, R. Clarenc, A. Tressaud, E. Durand, Journal of Fluorine Chemistry, 134 (2012) 35–43

A1492 – Detail kinetic analysis of the thermal decomposition of PLA with oxidized multi-walled carbon nanotubes

Nanocomposites of poly(l-lactic acid) (PLA) with oxidized multi-walled carbon nanotubes (MWCNTs-COOH) were prepared by solved evaporation method containing 2.5 wt% MWCNTs-COOH. From the thermogravimetric curves it can be seen that PLA/MWCNTs-COOH nanocomposite present a relatively better thermostability than PLA. The activation energy was calculated with the isoconvertional Ozawa–Flynn–Wall and Friedman's methods. For all the mass conversions, PLA has lower values than the nanocomposite. From the variation of the activation energy (E) with increasing degree of mass conversion, especially for the PLA, it was concluded that the decomposition of all the samples is taking place with a complex reaction mechanism with the participation of at least two different mechanisms. The best fitting of experimental data with theoretical models for PLA and PLA–2.5 wt% MWCNTs-COOH give nth-order for the first mechanism and nth-order with autocatalysis (Fn–Cn) for the second mechanism with different activation energies.
K. Chrissafis, Thermochimica Acta, 511 (2010) 163–167

A1485 – Thermal ignition and self-heating of carbon nanotubes: From thermokinetic study to process safety

A comprehensive investigation on the kinetics of combustion of multiwall carbon nanotubes (MWCNTs) produced by vapour chemical deposition has been undertaken. The kinetics parameters were determined from isothermal and non-isothermal combustion tests i.e. by both thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The activation energy of CNT combustion was found to be about 150 kJmol?1. The oxidation of carbon nanotubes (CNTs) appears to be a single step reaction well represented by a cylindrical shrinking core model. The consistency of this model was assessed both by comparing the activation energy extracted from TGA and DSC, and by theoretical considerations on the geometrical development of CNT oxidation. The influence of oxygen concentration on CNT combustion was also studied. Finally, these results combined with those obtained by self-ignition tests in baskets lead to recommendations for a safe handling and storage of CNTs.
A. Vignes, O. Dufaud, L. Perrin, D. Thomas, J. Bouillard, A. Janès, C. Vallières, Chemical Engineering Science 64 (2009) 4210 -- 4221

A1479 – Nanocomposites based on gelatin and montmorillonite. Morphological and thermal studies

Model gelatin/montmorillonite (Ge/MMt) composites were obtained for a variety of unmodified clay concentrations and in the absence of additives, with the main goal of evaluating the effect of the morphologies developed on the composites thermal stability. Morphologies turned form partially exfoliated to exfoliate/intercalated and eventually agglomerated with increasing clay loading, as was observed by atomic force microscopy. Formulations containing 3–10 mass% montmorillonite resulted in an enhancement of composites thermal stability due to stabilizing interactions between co-components, such as strong hydrogen-type bonds, in agreement with the partially exfoliated/intercalated morphologies. Higher clay concentrations showed lower stabilizing effect in agreement with the agglomerated structures developed and the less effective interactions between co-components.
J. F. Martucci, A. Vázquez, R. A. Ruseckaite, Journal of Thermal Analysis and Calorimetry, Vol. 89 (2007) 1, 117–122

A1451 – Thermal degradation kinetics of in situ prepared PET nanocomposites with acid-treated multi-walled carbon nanotubes

A series of PET/acid-treated multi-walled carbon nanotubes (MWCNTs) nanocomposites of varying nanoparticles’ concentration were prepared, using the in situ polymerization technique. TEM micrographs verified that the dispersion of the MWCNTs into the PET matrix was homogeneous, while some relatively small aggregates co-existed at higher filler contents. Intrinsic viscosity of the prepared nanocomposites was increased at low MWCNTs contents (up to 0.25 wt%), while at higher contents a gradual reduction was observed. The surface carboxylic groups of acid-treated MWCNTs probably reacted with the hydroxyl end groups of PET, acting as chain extenders at smaller concentrations, while at higher concentrations, on the other hand, led to the formation of branched and cross-linked macromolecules, with reduced apparent molecular weights. From the thermogravimetric curves, it was concluded that the prepared samples exhibited good thermostability, since no remarkable mass loss occurred up to 320 °C (.5%). The activation energy (E) of degradation of the studied materials was estimated using the Ozawa, Flynn, and Wall (OFW), Friedman and Kissinger’s methods. Pure PET had an E = 223.5 kJ/mol, while in the PET/MWCNTs nanocomposites containing up to 1 wt% the E gradually increased, indicating that MWCNTs had a stabilizing effect upon the decomposition of the matrix. Only the sample containing 2 wt% of MWCNTs exhibited a lower E due to the existence of the aforementioned cross-linked macromolecules. The form of the conversion function for all the studied samples obtained by fitting was the mechanism of nth-order auto-catalysis.
A. A. Vassiliou, K. Chrissafis, D. N. Bikiaris, J Therm Anal Calorim (2010) 100, 1063–1071

A1439 – Cation distribution in manganese cobaltite spinels Co32xMnxO4 (0 ? x ? 1) determined by thermal analysis

Thermogravimetric analysis was used in order to study the reduction in air of submicronic powders of Co3-xMnxO4 spinels, with 0 ? x ? 1. For x = 0 (i.e. Co3O4), cation reduction occurred in a single step. It involved the CoIII ions at the octahedral sites, which were reduced to Co2+ on producing CoO. For 0 < x ? 1, the reduction occurred in two stages at increasing temperature with increasing amounts of manganese. The first step corresponded to the reduction of octahedral CoIII ions and the second was attributed to the reduction of octahedral Mn4+ ions to Mn3+. From the individual weight losses and the electrical neutrality of the lattice, the CoIII and Mn4+ ion concentrations were calculated. The distribution of cobalt and manganese ions present on each crystallographic site of the spinel was determined. In contrast to most previous studies that took into account either CoIII and Mn3+ or Co2+, CoIII and Mn4+ only, our thermal analysis study showed that Co2+/CoIII and Mn3+/Mn4+ pairs occupy the octahedral sites. These results were used to explain the resistivity measurements carried out on dense ceramics prepared from our powders sintered at low temperature (700–750 °C) in a Spark Plasma Sintering apparatus.
H. Bordeneuve, A. Rousset, C. Tenailleau,,S. Guillemet-Fritsch, J Therm Anal Calorim (2010) 101, 137–142

A1437 – Synthesis of YAP phase by a polymeric method and phase progression mechanisms

The phase formation kinetics of YAP (YAlO3) synthesized through the polymeric precursor method was investigated by thermal analysis, X-ray diffraction and FT-IR spectroscopy. We demonstrated that the YAP synthesis is highly dependent on the heat and mass transport during all stages of the synthesis route. In the first stages, during the preparation of amorphous precursor, ‘‘hot spots’’ need to be suppressed to avoid the occurrence of chemical inhomogeneities. Very high heating rates combined with small amorphous particles are advantageous in the last stage during the formation of crystalline phase. We were able to synthesize nanosized particles of YAP single phase at temperatures around 1100 °C for future preparation of phosphors or ceramics for optics.
J. F. Carvalho, F. S. De Vicente, N. Marcellin,,P. Odier, A. C. Hernandes, A. Ibanez, J Therm Anal Calorim (2009) 96, 891–896

A1436 – Nanoscale spinel ferrites prepared by mechanochemical route. Thermal stability and size dependent magnetic properties

Among the many types of preparation and processing techniques, the nonconventional mechanochemical route has been recognized as a powerful method for the production of novel, high-performance, and low-cost nanomaterials. Because of their small constituent sizes and disordered structural state, nanoscale materials prepared by mechanochemical route are inherently unstable with respect to structural changes at elevated temperatures. Taking into account the considerable relevance of the thermal stability of nanoscale complex oxides to nanoscience and nanotechnology, in the present work, results on the response of mechanochemically prepared MgFe2O4 and NiFe2O4 to changes in temperature will be presented. Several interesting features are involved in the work, e.g., a relaxation of the mechanically induced cation distribution towards its equilibrium configuration, a disappearance of the superparamagnetism on heating, an increase of both the saturation magnetization and the Néel temperature with increasing particle size, and a core–shell structure of nanoparticles.
V. Sepelák, P. Heitjans, K. D. Becker, Journal of Thermal Analysis and Calorimetry, Vol. 90 (2007) 1, 93–97