Mesomorphic cyclolinear organosiloxane and organocarboxiloxane block copolymers

Cyclolinear organoxiloxane and organocarbosiloxane block copolymers have been obtained by a heterofunctional condensation reaction of α,ω-dioxy(decaorganocyclohexasiloxane-2,8-diyl)]s with α,ω-dichloropolydimethylsiloxanes and bis-(chlorodimethylsilyl)alkanes. Nearly all of the synthesized polymers exhibit at least two phase transitions, from mesophase 1 to mesophase 2 and from mesophase 2 to isotropic melt. The isotropization temperature of block copolymers decreases monotonically when the length of the siloxane spacer increases