Grafting of Polystyrene Onto the Cross Links in a Siloxane Elastomer

摘要

Hydroxyl-terminated chains of poly(dimethylsiloxane) were end-linked with a trimethoxysilane RSi (OCH3)3 where part of the R group was unsaturated. Styrene monomer was absorbed into portions of the resulting network and then radically polymerized to polystyrene (PS). Approximately half of the PS was unextractable, suggesting that at least some of this part was permanently grafted onto the cross-links. Stress-strain measurements in elongation were performed on an unmodified sample, and unextracted and extracted samples after modification with PS. Large increases in ultimate strength and rupture energy were observed for the modified networks, with both the grafted and extractable PS contributing to these increases. Reprints. (jes)