Synergistic effect of polypyrrole and reduced graphene oxide on mechanical, electrical and thermal properties of epoxy adhesives

Abstract

In the current work, a candid approach has been reported to synthesize epoxy based electrically conductive adhesives (ECAs) using synergistic effect of polypyrrole (PPy) and reduced graphene oxide (rGO) filler mixture. Further, an in-depth study has been done to investigate the adhesive, impact and thermal conductive properties of the developed ECAs. The fabrication of ECAs was performed by varying the concentration of PPy from 5 to 10 wt% and the content of rGO from 0.5 to 1.0 wt%, respectively. FTIR and XRD studies unveiled effective interaction of PPy, rGO and PPy/rGO filler mixture with epoxy resin in the adhesive systems. The lap shear strength showed enhancement as PPy, rGO and PPy/rGO filler mixture were introduced into the epoxy resin. Other mechanical properties such as tensile and impact strength of epoxy resin was found to be decreasing with the addition of PPy particles, while the incorporation of rGO and PPy/rGO filler mixture showed contrary results. The volume conductivity was enhanced up to 2.33 × 10−09 S/m which is four-orders higher than that of E resin, when 5 PPy/0.5 rGO filler mixture were introduced. The thermal conductivity of E-5 PPy/1.0 rGO adhesive exhibited optimum value of 0.41 W/mK among all the adhesives. The enhancement of storage modulus and thermo-stability of epoxy adhesive with the addition of PPy/rGO filler mixture were confirmed by DMA and TGA techniques, respectively.