Core-shell structured polyethylene glycol functionalized graphene for energy-storage polymer dielectrics: Combined mechanical and dielectric performances

Polydispersed graphene was synthesized by grafting a thin layer of water-soluble amine functionalized polyethylene glycol monomethyl ether (PEG-NH2). PEG-NH2 functionalized graphene (PEG@rGO) was then introduced into epoxy resin via a facile solution mixing method. Fourier-transform infrared (FTIR) spectroscopy, Xray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) verified that PEG was successfully grafted to the surface of graphene. The obtained PEG@rGO showed excellent dispersibility in solvents when compared to pristine graphene. As a "core-shell" filler, PEG@rGO filled epoxy nanocomposites displayed improved dielectric constant and reduced dielectric loss, exhibiting potential applications in energy storage capacitors. The mechanical strength and final decomposition temperature were also simultaneously increased.