| abstract |
Novel rubber-modified rigid silicone resins are disclosed. The novel resins are the copolymerized reaction product of (A) an organosilicon composition selected from the group consisting (I) an organosilicone resin, (II) hydrolyzable precursors of (I), and an hydrolyzate of (II), (B1) a first silicone rubber having a nonfunctional linear chain length between functional groups from 6 to 100 and (B2) a second silicone ruberr having terminal functional groups and a degree of polymerization from about 200 to 1,000. The novel rubber-modified rigid silicone resins of the invention show remarkably high fracture toughness, K Ic , and critical strain energy release rate G Ic . |