Humid heat aging of biphenyl epoxy resin: a combined study of experiments and simulations

Epoxy resins are commonly used as external insulating materials for high-voltage outdoor applications. To improve the moisture and heat resistance of epoxy resin materials, this research carried out experimental tests and theoretical simulations on a variety of epoxy resin materials, including the biphenyl type. The theoretical simulation used the Materials Studio software to model the biphenyl epoxy resin and bisphenol A-type epoxy resin at different humidities. The simulation results show that the biphenyl epoxy resin has a higher glass transition temperature, at which the water molecules have a smaller root-mean-square displacement and a lower probability of forming hydrogen bonds. Experimental tests illustrated that biphenyl-type epoxy resins exhibit enhanced stability, lower hygroscopicity, and minimal changes in the permittivity in hot and humid environments. The agreement between the theoretical simulations and experimental tests indicates that the simulation calculation method is applicable to studying the hygrothermal resistance of epoxy resin materials. This study also lays the foundation for improving various aspects of the performance of epoxy resin materials through simulations, thereby providing a theoretical basis for the development of hygrothermal-resistant epoxy resins.