Influence of Polyhedral Oligomeric Silsesquioxanes (POSS) on Thermal and Mechanical Properties of Polydimethylsiloxane (PDMS) Composites Filled with Fumed Silica

A series of novel PDMS composites filled with a given amount of fumed silica were first prepared using divinyl-hexa[(trimethoxysilyl)ethyl]-POSS as cross-linker by hydrolytic condensation in the presence of organotin catalyst. The crosslinking reaction, the morphology, thermal behaviors and mechanical properties of the novel PDMS composites were characterized by attenuated total reflection infrared spectroscopy, scanning electron microscope, thermogravimetric analysis and universal tensile testing machine, respectively. It was found that the resistances to thermal degradation, thermo-oxidative decomposition of the novel PDMS composites were greatly improved by incorporation of POSS cross-linker, compared with that of the reference material (MT-1). Meanwhile, we also found that their thermal properties and mechanical properties were gradually enhanced with the further increment in loading amount of POSS cross-linker. The pronounced enhancements in thermal properties and mechanical properties of novel PDMS composites were likely attributed to the increasing interaction of PDMS chains and aggregated particles from synergistic effect between POSS and fumed silica.