Synthesis and characterization of side chain liquid crystalline polymers

The series of side chain liquid crystal polymers are prepared using 4-hydroxybenzoic acid (HBA), hydroquinone and acryloyl chloride (AC) as the starting materials through stepwise alkylation and acylation reactions. By means of homopolymerization using BPO as the initiator at 60°C in 1, 4-dioxane, four side chain liquid crystalline polymers having different architectures are synthesized. The monomers and the polymers obtained are characterized by elemental analyses, FTIR and ¹H-NMR measurements. DSC and HS-POM are used to study the phase-transition temperatures and mesophase textures for both monomers and polymers. The thermal stability of the polymers is measured by TGA in the nitrogen atmosphere. It is found that the polymers are all qualified thermotropic side chain liquid crystalline polymers with excellent thermal stability and present nematic schlieren texture in wide liquid crystalline phase transition temperature.