Polycarbonate composites flame-retarded by poly(phenylsilsesquioxane)

摘要

Poly(phenylsilsesquioxane) (PPSQ) of ladder chain structure was synthesized and characterized, then used in flame-retarding polycarbonate (PC) in this article. The PC/PPSQ composites with different loading level of PPSQ were blended by twin-screw extruder and moulded. It was observed by SEM that the PPSQ particles were dispersed in PC in the size of 0.5-1.5 μm. In mechanical properties, addition of the PPSQ to PC could maintain fracture strain of the composites. In improving flame-retardancy of the PC, the PPSQ was verified to be very effective. The 6.0 wt% PPSQ could reduce peak heat release rate (PHRR) of the PC composites from 570 to 212 kW/m~2, and made it reach the combustion rating of UL 94 V-0 (1.6 mm). The char of the composites burnt after the cone calorimeter testing was intumescent, and exhibited structures of thin layered membranes. TG-FTIR analysis revealed that the PPSQ weakened CO2 release of the late thermal decomposition of PC.