Abstract
This study was performed primarily to investigate the effects of chemical modification on silica surface and the silica content on the thermal and gas barrier properties of a polyethersulfone (PES) matrix. The PES/SiO2 composites composed of PES and three species of SiO2 nanoparticles (AEROSIL A200, R805 and R974) were prepared by solution blending. The thermal behaviour, thermal stability, and morphology of the composites were studied by DSC, TGA and SEM. The oxygen barrier efficiency of the composites was characterized by use of an oxygen transmission rate (OTR) analyzer. The composites' properties, such as glass transition temperature (Tg), decomposition temperature (Td), and oxygen barrier, were found to improve. The Tgs of the composites increased significantly with the silica content and the 10 wt.% R805 composite exhibited the highest Tg, which was 28.7 °C higher than that of pure PES (193.8°C). The Tds of these composites increased from 4.9 °C to 10.6 °C with silica content ranging from 0.5∼10 wt.%. The added SiO2 leads to an increase in Tg and Td. The oxygen barrier effectiveness of the composites showed significant improvement when compared to pure PES. The 1 wt.% R974 composite exhibited the lowest OTR, a decrease of 62% when compared to pure PES. These results indicate that the PES/SiO2 composites have high potential for flexible polymer substrate applications.