Synthesis And Characterization Of Four Series Of Main-chain Liquid Crystalline Inomoers Containing Carboxylic Ion

Liquid crystalline polymers have excellent properties containing high modulus, high strength, chemical stability, dimensional stability and lower coefficient of thermal expansion. The rigid group of the liquid-crystal polymer plays the role as an enhancer to form higher fibril surface and aspect ratio than common reinforcement fiber, which improves the property of processing performance. The ionomer has been widely used in the field of print, in situ composites, nano-films and so on for the excellent performances talked above.In this paper, four series of main-chain liquid crystalline ionomers P1-P4 containing carboxylic ion were synthesized in the manner of solution condensation polymerization reaction by controlling the proportions of 1,4-benzenedicarbonyl chloride,4,4'-dicarboxy-dihenyi ether chloride, sebacic chloride,4,4'-biphenyldiol and 2,5-dihydroxybenzoic acid. The structures and properties of the liquid crystalline were characterized by FTIR, DSC, TGA, and POM. It is main-chain liquid crystalline ionomers with nematic schlieren textures. The polymers exhibited good thermal stability.The liquid crystalline polymers composed of 1,4-benzenedicarbonyl chloride,4,4'-biphe-nyldiol and 2,5-dihydroxybenzoic acid were synthesized. The effect of 2,5-dihydroxy-benzoic acid on thermal properties, textures and structures of the polymers was discussed. The glass-transition temperatures and melting point decreased with the increasing of 2,5-dihydro-xybenzoic acid.The polymers were observed under POM. Colorized liquid crystalline textures were obtained in mesogenic regions. The series of P2 based on P1 were synthesized by adding different content sebacic chloride into P1-1 which was synthesized by 4,4'-biphen-yldiol and 2,5-dihydroxybenzoic acid with a molar ratio 9:1. The Tg and Tm decreased and mesogenic regions increased with the increasing of sebacic chloride. The series of P2 exhibited nematic droplet and schlieren. The P2 were nemaic liquid crystal polymers according to the characters of textures of nematic phase.The series of P3 composed of 4,4'-dicarboxydihenyi ether chloride,4,4'-biphenyldiol and 2,5-dihydroxybenzoic acid were synthesized by way of solution polycondensation. Because of the rigid intensity, the Tg and Tm slowly decreased with the increasing of 2,5-dih-ydroxybenzoic acid in the series of P3. And this series of ionomers exhibited colorized liquid crystalline textures in mesogenic regions. The series of P4 were synthesized based on series P3 by adding different content sebacic chloride into P3-1 which was synthesized by 4,4'-biphe-nyldiol and 2,5-dihydroxybenzoic acid with a molar ratio 9:1. The Tg and Tm slowly decreased with the increasing of sebacic chloride. The nematic droplets and schlieren textures belonging to the nemaic liquid crystal were obtained in series of P4. So the series of P4 are nemaic liquid crystalline polymers.