Liquid Crystalline Polymers

The study of the structure and properties of liquid crystalline polymers (LCPs) is fascinating as well as challenging from the points of view of scientific understanding and industrial applications. The LCPs have many attractive properties, particularly when compared to engineering polymers (EPs). They are mechanically stronger than the EPs; thermal expansivity is lower and is stable at higher temperature. The LCPs are extremely unreactive and inert, and highly resistant to fire. They have numerous technological advanced applications that are increasing day by day. The structure–property relationship is still far from being completely understood. The presence of both long-range order and disorder makes the subject of LCPs very interesting. The LCPs may be formed either by dissolving a polymer in a solvent (lyotropic liquid crystal polymers LLCPs) or by heating a polymer above its glass or melting transition point (thermotropic liquid crystal polymers TLCPs). Almost all the known thermotropic LCPs are polyethers. This chapter is devoted to the description of rheology, types, synthetic routes, structure–property dependences and properties of TLCPs composed of calamitic as well as disc-shaped mesogenic molecules.