Effects of macromolecular silane coupling agent on the mechanical properties of nano-SiO2/cyanate ester nanocomposites

In this paper, a novel kind of high-performance composite was developed by blending 2, 2′-Bis(4-cyanatophenyl)isopropylidene with nano-silica (nano-SiO2), in which the nano-SiO2 was modified by a tri-copolymer of styrene, vinyltrimethoxysilane and methacrylate. The transmission electron microscopic and scanning electron microscopic micrographs indicated that the modified nano-SiO2 particles were dispersed in the 2′-Bis(4-cyanatophenyl) isopropylidene matrix homogeneously. Compared with pure 2′-Bis(4- cyanatophenyl)isopropylidene resin, the impact and flexural strengths of the nanocomposite materials were improved markedly with up to 58% and 40% increasing magnitude, respectively, and the storage modulus showed a 58% increase in the glassy state. Meanwhile, the glass transition temperature of the resulting composite was 310°C, which was 30°C higher than that of pure 2′-Bis(4-cyanatophenyl)isopropylidene resin. It was found that the modified nano-SiO2 that possessed good dispersion in the 2′-Bis(4- cyanatophenyl)isopropylidene matrix had a significant influence on the mechanical and thermal properties of the 2′-Bis(4-cyanatophenyl) isopropylidene resin. All the improvements of properties could be attributed to the effect resulting from the changes of both interface adhesion and dispersibility of filler in matrix.