Synthesis And Characterization Of Side-Chain Liquid Crystal Polyacrylate

Side-chain liquid crystal polymers, is a new style function materials avalanched theses years. Side-chain liquid crystal polyacrylate with good photo-electricity performance, one of polymers, has good application potentiality in the field of information storage and gas chromatographic analysis. Two side-chain liquid crystal polyacrylates , one with flexible spacers and the other without flexible spacers , were prepared in different processes.In the first process, side-chain liquid crystal polyacrylate with flexible spacers was synthesized, which is divided into five steps: firstly, 4-(ω-ethoxy)-benzoic acid was made by p-hydroxybenzoic acid (HBA) with ethylene chlorohydrin, and the flexible spaces were added into HBA; secondly, 4-(ω-acrylic ethoxy)-benzoic acid was produced by the product with acrylic acid; thirdly, it was acylchloridized with thionyl chloride; fourthly, after esterification between the acylchloridized product and HBA, they generated the acrylic acid monomer with mesogenic unit; finally, side- chain liquid crystal polyacrylate with flexible spacers were obtained by free radical polymerization of the monomer with mesogenic unit. In the second process, side-chain liquid crystal polyacrylate without flexible spacers was synthesized, which was divided into four steps: firstly, dimmer of p-hydroxybenzoic acid (DHBA) as mesogenic unit was produced by acylation of acetic anhydride with HBA, acylchloridization with thionyl chloride, esterification with HBA and hydrolyzation in alkali condition ; secondly, acyloyl chloride acrylate was obtained by acylchloridization of benzoic acid and thionyl chloride, reaction with acrylic acid; thirdly, acrylic acid monomer with mesogenic unit was obtained by reaction of acyloyl chloride acrylate and DHBA; at last, by free radical polymerization, side-chain liquid crystal polyacrylate without flexible spacers was obtained.Result of performance measurement of the two side-chain liquid crystal polyacrylate by melting point apparatus,IR,DSC and POM shows that they are of perfect liquid crystal performance . the former nematic liquid crystal and the latter smectic liquid crystal , and their liquid crystal performance is very stable , which may be caused by the hydrogen bond of terminal carboxies.