Assembly of Ordered Polystyrene Nanoparticles on Self-Assembled Monolayers
Pages 202-209
Ortal Lidor-Shalev, Hagit Aviv and Yitzhak Mastai

DOI: http://dx.doi.org/10.6000/1929-5995.2015.04.04.5

Published: 12 January 2016

Abstract: Spontaneous assembly of nanoparticles onto a surface is a promising bottom-up concept for the fabrication of new functional materials that can be used for various applications in the nanotechnology. In this paper, we describe a system based on gold/polystyrene (Au/PS) Janus particles arranged onto Au self-assembled monolayer (SAM) of 1-dodecanthiol (NDA). The micro-size Au/PS Janus particles are self-assembled onto Au surface and are dissolved into polystyrene (PS) nanoparticles. The SAM of NDA plays two different roles; it dissolves the original Au/PS Janus particles and organizes the PS nanoparticles onto the Au surface. Overall, our proposed method for the assembly of large-scale area nanoparticles can be extended for further uses in the surface science.

A Simple and Efficient Approach to Cellulose/Silica Composite Aerogel with High Silica Utilization Efficiency
Pages 56-61
Chong Lin, Ang Li, Yang Cao and Lingbin Lu

DOI: http://dx.doi.org/10.6000/1929-5995.2015.04.01.7

Published: 17 April 2015

Abstract: Cellulose aerogel is a fascinating material with high porosity, low density and biocompatibility. However, cellulose aerogel lacks sufficient thermal stability. Recombination between cellulose aerogel with silica is efficacious for enhance the cellulose aerogel’s thermal stability.This work described a simple and efficient approach to the cellulose/silica composite aerogel via a dropwise manner, using tetraethoxysilane as silicon source and NaOH solution as cellulose solvent. The result showed that the thermal stability of cellulose aerogel was enhanced by introducing silica. And by this manner, the utilization efficiency of silica was up to 95%. The composite aerogel had a low density and a high porosity, which promised the material a good heat insulation performance, and the thermal conductivity of the composite aerogel was low to 0.0161W/(m·K). Moreover, by adjusting cellulose concentration and tetraethoxysilane amount, the density, porosity and thermal conductivity of the composite aerogel could be controlled. This work contributed to improving the utilization efficiency of silica for the composite aerogel with better performances.

Effect of Cenosphere Fly Ash on the Thermal, Mechanical, and Morphological Properties of Rigid PVC Foam Composites
Pages 1-14
Parisa Khoshnoud and Nidal Abu-Zahra

DOI: http://dx.doi.org/10.6000/1929-5995.2015.04.01.1

Published: 17 April 2015

Abstract: Cenosphere fly ash is a byproduct of coal combustion processes of power plants. It is composed of hollow, hard shelled, minute spheres, which are made up of silica, iron, and alumina. In this study, cenosphere fly ash is incorporated into rigid PVC foam to improve thermal and mechanical properties of their composites. Microstructural, physical, mechanical, and thermal properties of rigid PVC foam extruded with different loadings of cenosphere fly ash (6, 12, 18phr) are characterized. The measured density of the extruded PVC foam composites increased with cenosphere content, indicating a hindrance to the foaming process. Tensile and flexural mechanical properties improved at higher cenosphere content, while the impact strength decreased at initial loading of 6 phr of cenosphere particles and remained steady at higher loadings. Thermal characterization of the extruded samples showed that glass transition temperature remained almost unaffected, while TGA analysis revealed no change in the initial degradation temperature and significant improvement in the final degradation temperature. Thermo-mechanical properties measured by DMA revealed a remarkable improvement in the viscoelastic properties of the composites reinforced with cenosphere particles. SEM analysis of the composites microstructure confirmed that the cenosphere particles were mechanically interlocked with good interfacial interaction in the PVC matrix.

5-Hydroxy-6-Methyluracil as a Polyvinyl Chloride Stabilizer
Pages 123-126

R.M. Akhmetkhanov, I.T. Gabitov, A.G. Mustafin, V.P. Zakharov and G.E. Zaikov

DOI: http://dx.doi.org/10.6000/1929-5995.2015.04.02.4

Published: 28 July 2015

Abstract: Kinetic regularities of thermooxidative dehydrochlorination of rigid and plasticized PVC in the presence of 5-hydroxy-6-methyluracil have been studied. The high antioxidant efficacy of 5-hydroxy-6-methyluracil in the process of polymer degradation has been revealed. It is shown that the studied uracil significantly slows down the process of accumulation of hydroperoxides in oxidation of dioctyl phthalate the plasticizer of PVC, which is the cause of a significant slowdown in the rate of decomposition of the plasticized polymer.