Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 5.Synthesis and Mesomorphic Behavior of Poly(2-(4-Cyano-4'-Biphenyl)oxy)ethyl Vinyl Ether-co-8-(4-Co-4'-Biphenyl)oxyoctyl Vinyl Ether

摘要

The synthesis and characterization of poly 2-(4-cyano-4 '-biphenyl)oxy ethylvinyl ether poly(6-2), poly 8-(4-cyano-4'biphenyl)oxyocctyl vinyl ether poly(6-8) and poly (6-2-co6-8) X/Y (where X/Y is the molar ratio of the two monomericstructural units) with degrees of polymerization of about 10 and narrow molecular weight distribution are described. Both homopolymers and copolymers were prepared by living cationic polymerization and copolymerization of 6-2 and 6-8. During the first heating scan poly(6-2) presents an inverse monotropic s sub c mesophase. During subsequent heating and cooling scans, this polymer is amorphous regardless of the thermal history of the sample. Poly(6-8) exhibits an enantiotropic s sub a mesophase. Both during the first and subsequent haeting and cooling scans, the phase diagram which plots the dependence of mesomorphic transition temperatures as a function of copolymer composition presents a discontinuity. Keywords: Side chain liquid crystalline polyethers and copolyethers, Living cationic polymerization)