Enhanced thermal and mechanical properties of functionalized graphene/thiol-ene systems by photopolymerization technology

Abstract

Functionalized graphene nanosheets (FGNSs) were synthesized through surface modification with 3-mercaptopropyl trimethoxysilane and then incorporated into thiol-ene using photopolymerization technology. The structure and morphology of GO, GNS and FGNS were characterized by AFM, XRD, TEM, XPS, FTIR and 29Si NMR. The incorporation of functionalized graphene nanosheets enhanced the thermal properties of thiol-ene nanocomposites. The initial thermal degradation temperature of thiol-ene was increased from 249 °C to 362 °C and a 30 °C increment in the glass transition temperature (Tg) was also achieved with only 1.5 wt% FGNS. The storage modulus of thiol-ene was improved by 138% at 1.5 wt% loading of FGNS. By contrast, untreated GNS/thiol-ene nanocomposites exhibited relatively lower thermal properties and storage modulus than its modified-GNS counterpart. The excellent reinforcements were attributed to good dispersion of FGNS and strong interfacial adhesion between FGNS and thiol-ene matrix as supported by SEM images of the fracture surfaces and TEM. The covalent functionalization of graphene with silane reported herein will provide a simple method to fabricate UV-curable nanocomposite coatings with effectively enhanced thermal and mechanical properties.