Surface Effect of Silica Nano-Particles with Different Size on Thermotropic Liquid Crystalline Polyester Composites

Abstract

Interface properties of nano-silica/thermotropic liquid crystalline polyesters (TLCP) composites were investigated by X-ray diffraction analysis and differential scanning calorimetory. The crystallinity of TLCP in the composites drastically decreased with an increase of nano-silica content, depending on the surface area of the silica particles. Little size effects (40-400 nm) in the particles and strong interaction between silica surface and the C=O moieties of TLCP were observed by IR analysis. The glass transition temperature of TLCP (<20 nm) in silica surface increased about 20˚C higher than that in bulk.

Interfacial region of poly(n‐butyl acrylate)/silicon oxide

“…We previously investigated the interfacial regions between PnBA and alumina nanoparticles, 26 and we found that they were enriched with PnBA in a trans ‐ trans conformation. The XRD patterns of PnBA mixed with silica nanoparticles differed from that of neat PnBA.…”

“…The weight percentages of silica nanoparticles in the samples are shown in parentheses. The DSC curve of each sample was normalized based on the weight of the polymer in the sample 25,26 . The DSC curves of neat PnBA and the PnBA/silica composites showed that a glass transition occurred near −54°C.…”

“…The DSC curve of each sample was normalized based on the weight of the polymer in the sample. 25,26 The DSC curves of neat PnBA and the PnBA/silica composites showed that a glass transition occurred near −54 C. In the DSC curve of the PnBA/silica composite, a change in the specific heat resembling a glass transition occurred near 34 C, which was designated the sub-glass transition temperature (sub-T g ). A change in the specific heat was also observed at −54 C, which was close to the T g of the bulk sample.…”

Effect of tacticity of poly(methyl methacrylate) on interfacial region with silica in polymer nanocomposite

“…The curves in the figures were normalized by the polymer weight. [ 24,25 ] The DSC curves of the neat PMMAs in Figures 1‐3 were obtained from the samples prepared by casting PMMA/toluene solutions. The T g values of the neat st ‐, at ‐, and it ‐PMMAs were indicated at 104.0°C, 98.5°C, and 50.8°C on the DSC curve, respectively, and the values were approximately the same as those of the as received samples.…”

Structure of polyacrylate/nanoparticle interfaces

“…The numbers in parentheses indicate the weight percentages of the nanoparticles in the samples. The curves in the figure were calculated by subtracting the pattern of the nanoparticles from those of the mixed samples [14]. Two main peaks that are characteristic of the XRD pattern of polyacrylates were observed.…”