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

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 (T_g) was also achieved with only 1.5wt% FGNS. The storage modulus of thiol-ene was improved by 138% at 1.5wt% 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. © 2013 The Authors.