In Situ NMR Measurement of Novel Silicone Elastomer Obtained by Cross-Linking of Silicones Having Phenylene Backbone and Hyperbranched Molecular Architectures

Novel silicone elastomer was obtained by cross-linking reaction of thermal hydrosilylation reaction between poly(oxysilphenylenesiloxydisiloxane) having vinyl groups in side chain and SiH-terminated hyperbranched polycarbosiloxane. In situ measurements using solid-state 1 H NMR were performed during the cross-linking reaction on heating. The results suggest that the cross-linking reaction was accelerated beyond 110 °C. Two overlapping reaction mechanisms reflect the characteristic molecular structures of poly(oxysilphenylenesiloxydisiloxane) having vinyl groups and SiH-terminated hyperbranched polycarbosiloxane. A possible structural model to satisfy both reaction mechanisms is proposed to characterize the development of the cross-linking reaction.