Restudy of the Old Poly-2,5-di(benzoyloxy)styrene as a New Liquid Crystal Polymer

The 40 year old polymer, poly-2,5-di(benzoyloxy)styrene, has been restudied from the view point of the "mesogen-jacketed liquid crystal polymer." This old polymer was synthesized in 1952 as a precursor of an electron exchange polymer and is now found to be thermotropically liquid crystalline, from which the characteristic banded texture of rigid and semi-rigid liquid crystal polymers may be obtained. The monomer of this polymer, 2,5-di(benzoyloxy)styrene, was then also not realized as liquid crystalline, is now found to be liquid crystalline forming too. This finding offers probably the first example of liquid crystal rigid rod-like molecules with lateral but without terminal substitutions. The synthesis and primary characterization of a series of the closely related polymers poly-2,5-bis[(4-substituted-benzoyl)oxy]styrenes are also reported.