Novel electrically conductive epoxy/reduced graphite oxide/silica hollow microspheres adhesives with enhanced lap shear strength and thermal conductivity

Abstract A novel preparation method was employed for development of epoxy based electrically conductive adhesives (ECAs) by utilizing reduced graphite oxide (rGO, conductive filler) and silica hollow microspheres (SiHM, non-conductive hollow microsphere). The ECAs was fabricated by considering three different ratios of rGO:SiHM such as 30:10, 40:10 and 50:10. The lap shear strength and unnotched impact strength was found to be increasing with the inclusion of filler mixture, while there was a decrease in tensile and notched impact strength. The electrical conductivity of unmodified epoxy adhesive was enhanced by six orders up to 8.06 × 10−07 with the incorporation of 50:10 ratio, whilst the percolation threshold was achieved at 30:10 ratio of rGO:SiHM. The thermal conductivity (Tc) was increased up to 128% as 50:10 ratio was introduced within the epoxy resin. The conductive adhesive formulations represented higher storage modulus along with lower Tg values in comparison to the pristine epoxy resin as detected through Dynamic mechanical analysis (DMA).