An MD-based physical characteristics analysis on the PI/EP duo-layer composites, impacting of diamino groups

Owing to the possible interfacial mismatching, the insulation performance in the polyimide-Epoxy (PI-EP) dual-layer composite structures would be reduced. In this paper, molecular dynamics simulations are used to study changes in various key physical characteristics of PI-EP composites agented by diamino groups, as well as the in-depth mechanisms. Particularly, the thermal-dynamics and dielectric characteristics were analyzed. Results indicated that agented by 4,4′-Diaminodiphenyl sulfur (SDA), the glass transition temperature was increased by 5 %, coefficient of thermal conductivity was increased by 18 %, and dielectric permittivity was reduced by 6 %. In addition, the density functional theory based calculations were applied to clarify the effects of diamino groups on the physical characteristics of the duo-layer composite structures, in the scope of electronics and energies. Agented by SDA, the duo-layer PI-EP composite is more suitable for the solid insulation of power electronics transformers.