“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°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.