Enhancement of thermal conductivity of polymethyl methacrylate-coated graphene/epoxy composites using admicellar polymerization with different ionic surfactants

In this study, thermally conductive graphene/epoxy composites were prepared from graphene and coated with polymethyl methacrylate (PMMA) using admicellar polymerization. In this process, the surfactant plays a key role, and two types of ionic surfactants [sodium dodecyl sulfate (SDS) and, cetyltrimethylammoniurn bromide (CTAB)] were used. PMMA-functionalized graphenes using SDS (S-PfRG) and CTAB (C-PfRG) were prepared as fillers, and PMMA was coated on the graphene in different forms). Both S-PfRG and C-PfRG were fabricated into epoxy composites showing different thermal conductivities. In the S-PfRG/epoxy composites, S-PfRG improved the interfacial adhesion between the filler and matrix, but because of the coating of PMMA, graphene was presented in an aggregated form. However, the C-PfRG/epoxy composite exhibited not only good interfacial adhesion but also well-dispersed graphene in the matrix. As a result, the thermal conductivity was increased to 0.670 W/mK, which was a 403% increase when compared to that of the untreated graphene/epoxy composite.