Preparation and performance of epoxy resin-based thermal conductive composites with different morphologies of ZnO

The morphology of filler exerts a momentous influence on the construction of heat conduction path in polymer matrix. In this paper, ZnOs@T-ZnOw/EP composites was prepared by mixing spherical zinc oxide (ZnOs) powder with tetra-needle like ZnO whiskers (T-ZnOw). By changing the mixture ratio of ZnOs and T-ZnOw, the thermal conductivity of ZnOs@T-ZnOw composite was optimized. When the filler content was 11.08% vol., the thermal conductivity of the composite with 40 wt% ZnOs and 60 wt% T-ZnOw reached the maximum 0.52 W(m K) −1 , which was 2.76 times higher than that of the pure epoxy resin. Meanwhile, the obtained composite showed good insulation properties. This experiment explored the influence of packing topography on the composition of thermal conductivity pathways and other properties, and revealed the thermal conductivity mechanism of filled thermal conductive composites. Graphical Abstract Figure (I) shows the SEM cross-sections of ZnOs@T-ZnOw/EP composites; Fig. (II) demonstrates the model diagram of filler structure under three different filling quantities; Fig. (III) presents a schematic diagram of the heat conduction mechanism; Fig. (IV) exhibits the thermal conductivities of pure EP and ZnO/EP composites. Highlights Optimized the heat conduction path of composite materials through the synergistic effect of fillers. Zinc oxide powder with high sphericity was prepared by sol–gel method. The excellent insulation and mechanical properties of epoxy resin are retained as much as possible.