''Liquid crystalline'' thermosets from 4,4'-bis(2,3-epoxypropoxy)biphenyl and aromatic diamines

Pure 4,4'-bis(2,3-epoxypropoxy)biphenyl (1) has been synthesized and its mesophase behaviour has been investigated. 1 forms a monotropic nematic mesophase with a virtual clearing temperature of 109 degrees C. 1 has been cured with 2,4-diaminotoluene (3), 4,4'-diaminobiphenyl (4), and 4-aminophenyl 4-aminobenzoate (5) to investigate the possibility of formation of anisotropic networks. Virtual clearing temperatures of the diamines indicate that liquid crystalline thermosets (LCT's) might be obtained with 4 and 5. Crystallization of oligomeric products from the isotropic melt of 1 with 3 or 4, respectively, occurred on isothermal curing without formation of a mesophase, while a nematic LCT was obtained with 5.