Zinc Oxide Tetrapod-Based Thermally Conducting Epoxy Systems for Aerospace Applications

Abstract

Zinc oxide tetrapod whiskers (T-ZnO) with uniform morphology were processed by thermal evaporation and condensation technique. This was used as filler in epoxy matrix resins to formulate room temperature curable, thermally conducting and high-strength composite adhesive systems. Adhesive compositions with varying extend of T-ZnOs were processed and cured using an ambient temperature curable amine hardener. Adhesive formulations which contain the same extent of conventional irregularly shaped zinc oxide particles were also processed for comparison. Various formulations were evaluated for lap shear strength (LSS), thermal conductivity and morphological examinations. Epoxy-TZnO-based adhesive formulations exhibited higher lap shear strength and thermal conductivity compared to their conventional zinc oxide-based counterparts. Thus, an optimized epoxy-TZnO formulation exhibited 42% improvement in LSS and 77% in thermal conductivity than their zinc oxide counterparts. Fracture morphology revealed a rough texture and uniform distribution of T-ZnO in the epoxy resin system.