Synthesis, phase transitions, and mesomorphic state in transtactic cyclolinear organosiloxane copolymers

Transtactic cyclolinear organosiloxane copolymers were obtained by heterofunctional condensation reaction of trans-2,8-dioxydecaorganocyclohexasiloxanes with α,ω-dichloropolydimethylsiloxanes or bis-(chlorodimethylsilyl)alkanes. It is shown that transtactic copolymers exhibit high crystallinity, regardless of the nature of organic substituents in the organosilsesquioxane fragment of cyclohexasiloxane. Above the melting point one of the copolymers is in the mesomorphic state and reveals a two-stage transition from mesophase to the isotropic melt