Abstract: Nano-SiO2 was modified with a coupling agent (KH-570), and was mixed with methyl methacrylate and styrene. The system was subjected to a suspension polymerization leading to P(MMA-St)/nano-SiO2 composites, in which Nano-SiO2 was evenly dispersed in the matrix. The structure and properties of the composites were characterized using Fourier transform infrared spectroscopy, gel permeation chromatography, thermal gravimetric analysis, TEM, universal testing machine, and torque rheometer. Because of the interaction between nano-SiO2 and P(MMA-St),the molecular weight became larger, and the molecular weight distribution became narrow. Thermal stability and mechanical performance of the composites were significantly improved.

Key words: methyl methacrytate, styrene, nanosilica, suspension polymerization, mechanical property