Epoxy-based composites with enhanced thermal properties through collective effect of different particle size fillers

Abstract

Taking advantages of excellent adhesion and insulating properties, polymer-based thermal interface materials have been widely used in electrical and electronic industry. However, applications was limited due to the existence of high interfacial resistance and poor mechanical properties resulted from poor dispersion and weak interfacial adhesion of thermal conductive fillers in the polymer matrix. Herein, different sizes of aluminum oxide microparticle was used as thermal conductive fillers to fabricate a series of high thermal conductive epoxy composites, and the effect of fillers loading ratio on the properties of thermal conductive, mechanical, thermal stability was further analyzed. The optimum composite exhibits a high thermal conductivity (1.91 ± 0.02 W·m−1·K−1) at a loading ratio of 1: 2 (20-μm: 70-μm, mass ratio), which is equivalent to a thermal conductivity enhancement of 950% in comparison with pure epoxy resin. The outstanding properties of the as-prepared composite is mainly attributed to the effective conductive network formed by different size fillers that the smaller particles act as a bridge to connect the larger one. This work has proved by Agari model that combining different sizes Al2O3 as fillers is a workable way to obtain composite with high thermal conductivity and it is expected to provide a reliable route for the preparation of thermally conductive composites with different particle sizes.