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

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 x 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 (T-c) 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 T-g values in comparison to the pristine epoxy resin as detected through Dynamic mechanical analysis (DMA).