Electrochemical polymerization of carbon fibers and its effect on the interfacial properties of carbon reinforced epoxy resin composites

Polyacrylonitrile (PAN)-based carbon fibers (CFs) were electrochemically deposited and graphene oxide (GO) and three different kinds of comonomers, including diacetone acrylamide (DAAM), acrylic acid (AA) and phenol (Pheno), were electrografted onto CF surfaces. Compared with untreated CFs, the tensile strength of GO-DAAM, GO-AA and GO-Pheno electrografted CFs increased by 5%, 22.6% and 17%, respectively. The surface microstructure of CFs before and after the electropolymerization treatment were subsequently performed by scanning electron microscopy (SEM), Infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), Raman spectrometer (Raman) and surface tension/dynamic contact angle device. With the electrografting of GO-comonomers onto CF surfaces, the characteristic striations along the fiber axis became less well-defined and much more functional groups were introduced onto electrografted CF surfaces. Results also showed that the three-dimensional composite structure was formed through the grafting of GO-intermediate graft polymers onto CF surfaces, which could enhance the final interfacial properties of CF reinforced epoxy composites.