Polyorganosiloxanes with linear and cyclic segments

Abstract

Hydride transfer to the tricyclic siloxane compound, i.e. 1,7-dimethyl-1,7-divinyl-3,5,9,11-tetraphenyltricyclohexamethylsiloxane, from the α,ω-methylphenyl-siloxane dihydride and the α,ω-dimethylsiloxane hydride oligomers yielded polymers with linear-structure polydiorgano- and polycyclosiloxane segments. Hydride transfer reaction between diallyl isophthalate and the α,ω-dimethylsiloxane dihydride oligomers yielded polymers containing molecules with linear siloxane and aromatic segments. The glass temperatures ( T g) were determined for all the produced polymers. The larger the contents of tricyclic siloxane and also of aromatic segments in the linear siloxane chains, the larger were the T g. The TGA of the polymers showed their resistance to thermal-oxidative degradation to increase with the content of tricyclic siloxane segments and to decrease as the content of aromatic segments increased in the linear siloxane chain.