Synthesis of cyclolinear polymethylsiloxanes with two reactive groups and liquid-crystalline polymers on their basis

Abstract

Cyclolinear polymethylsiloxanes with reactive vinyl groups at the silicon atoms in the fragment SiO3/2 have been synthesized for the first time by heterofunctional polycondensation of [2,6(2,8)-dichloro-2,6(2,8)-divinyl]methylcyclotetra(hexa)siloxanes with the corresponding dihydroxy derivatives. Their hydrosilylation with chlorodimethylsilane gives rise to cyclolinear polymers with 2-chlorodimethylsilylethyl substituents, hydrolysis of which leads to the corresponding hydroxy derivatives. Liquid-crystalline polymers with mesogenic cyanobiphenyl groups have been synthesized by hydrosilylation with (4’-cyanobiphenyl-4-yl) 11-(1, 1, 3, 3-tetramethyldisiloxanyl)undecanoate. The structures of the polymers obtained have been studied by 1H and 29Si NMR and IR spectroscopy, GPC, viscometry, X-ray diffraction, and polarization optical microscopy.