Low thermal expansion coefficient and high thermal conductivity epoxy/Al2O3/T-ZnOw composites with dual-scale interpenetrating network structure

Substrates with high thermal conductivity (TC), outstanding mechanical strength, and low coefficient of thermal expansion (CTE) and dielectric constant are ideal materials for electronic packaging. The preparation of ceramic/polymer composites is a feasible method to meet the above requirements. Herein, a kind of reticulated porous alumina ceramics (RPCs) was introduced into epoxy resin (EP) doped with tetrapod-like zinc oxide whiskers (T-ZnOw) to produce EP/Al2O3/T-ZnOw composites with continuous interpenetrating network structure. The addition of 11.7 vol% RPCs and 6 vol% T-ZnOw caused an increase of TC to 1.968 W.m(-1).K-1. Compared to pure EP, the CTE of EP/11.7 vol% Al2O3/6 vol% T-ZnOw composite was reduced by an order of magnitude and the flexural modulus increased 5.7 times. The novel substrate materials, fabricated via the polymer replica and vacuum impregnation methods, featured attractive properties for potential use in electronic packaging applications with low fillers loading.