Design of an experimental study of high through-plane thermal conductivity hybrid epoxy composite insulation with superior dielectric strength

Thermally conductive polymers are highly desired as electrical insulation materials in power-electronic and electrical machines toward high power density and payload efficiencies. This paper investigates the thermal conductivity of hybrid epoxy composites containing talc nanoclay, boron nitride (BN) clusters, and zinc oxide (ZnO) particles using the Design of Experiment (DoE) approach. A statistical model of the composite thermal conductivity based on the compositions of the components has been established with an R-squared of 98.17%. The effects of shapes, sizes, filler thermal conductivity, and the structured network of the fillers are discussed. The structured edge-connecting BN nanosheets endowed in nanostructured BN-clusters play a critical role in composite thermal conductivity enhancement. The thermal conductivity with the optimized formulation could reach 1.3 W m(-1) K-1, which is 6x higher than that of neat epoxy resin, while maintaining superior dielectric properties. The results of DoE analysis can be widely applied to the design of polymer composites with optimal formulations.