Research on the Preparation and Properties of Biphenol Liquid Crystal Epoxy Resin

Abstract Various crystalline epoxy resins with liquid crystal properties are widely used as electronic packaging materials. However, most liquid crystals have specific molecular structures, and the synthesis methods and processes used are complicated and costly.In this study, 4,4′-biphenol and epichlorohydrin were used as synthetic monomers to synthesize oligomeric 4,4′-diglycidyl ether of biphenyl (BP) epoxy resin containing biphenyl moieties. Moreover, the synthesis method was optimized to obtain a higher-quality product. The thermodynamic properties of the new product and the cured product of E51 epoxy resin were compared to highlight the advantages of liquid crystal epoxy resins.The results showed that the epoxy equivalent of the liquid crystal epoxy resin obtained by the optimized synthesis method was 184.4 g/eq, which was lower than that of the liquid crystal epoxy resin synthesized by the traditional one-step method (200.2 g/eq). Compared with the cured sample of E51, its glass transition temperature (Tg) reached 277.2°C, the initial storage modulus was 2308 MPa, and the initial decomposition temperature reached 389.85°C. Therefore, it can be concluded that optimizing the synthesis steps can improve the performance of liquid crystal epoxy resins. And compared with ordinary epoxy resins, liquid crystal epoxy resins have more excellent performance. The research results provide an optimization idea for the synthesis method of liquid crystal epoxy resins and provide data support for its application through the study of curing kinetics.