Chavan, N: Thermotropic Liquid Crystalline Polyesters

This chapter presents detailed literature survey of liquid crystalline polymers. The major emphasis is given to structure property relationship of thermotropic liquid crystalline polyesters. Triad based liquid crystalline polyesters showed thermal stability above 3000C and solubility in chlorinated solvents. Cholesteric liquid crystalline polyesters are also explained due to its high strength, and high modulus. High performance cholesteric liquid crystalline polyesters derived from isosorbide is reported in detail, because it is easily accessible from renewable resources. As far as lyotropism is concerned, Preston‘s hypothesis of lowering reactivity by the introduction of nitro group at ortho to amino, which opened a new route to synthesise high performance and soluble lyotropic liquid crystalline polyamides, is also presented. These polyamides can be a better substitute to KEVLAR. The current trend of incorporating nanoparticles into thermotropic liquid crystalline polyesters to improve mechanical, thermal and water resistant properties are described. Improvements in storage modulus and glass transition temperature were observed.