Effect of the Polymer Backbone on the Thermotropic Behavior of Side-Chain Liquid Crystalline Polymers

摘要

Poly(ephichlorohydrin) (PECH) and poly(2,.6-dimethyl-1,4-phenylene oxide) (PPO) containing pendant mesogenic units separated from the main chain through spacers of zero to ten methylene units were synthesized and characterized in order to test the 'spacer concept'. Both polymers were modified by phase transfer catalyzed esterifications of the chloromethyl groups (PECH) or the bromobenzyl groups (brominated PPO) with potassium omega-(4-oxybiphenyl) alkanoates and potassium omega-(4-methoxy-4'-oxybiphenyl)-alkanoates. While PPO required ten methylene units as spacer and 4,4'-methoxybiphenyl as mesogen to present thermotropic liquid mesomorphism, PECH required no spacer. Keywords: Side-chain thermotropic liquid crystalline polymers.