PECVD application to obtain polymer coated graphene nanoplatelets and development of new epoxy nanocomposites

Abstract

In this study, graphene nanoplatelets (GNPs) were synthesized from graphite by a liquid-phase exfoliation (layer separation) method, and their surfaces were functionalized with poly(glycidyl methacrylate) (PGMA) by using the rotating bed plasma-enhanced chemical vapor deposition (PECVD) method. Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and thermogravimetric (TGA) analyses were performed to characterize the unmodified (u-GNP) and modified GNP (PGMA-GNP). Epoxy nanocomposites were prepared with both types of GNPs at different loading levels (0.1-2% by weight). The role of the surface modification of the GNPs on the mechanical, thermal, electrical conductivity, contact angle, water sorption, and corrosion properties of the epoxy nanocomposite coatings was also investigated. Consequently, the tensile strength and Young's modulus of the epoxy resin (ER)/PGMA-GNP nanocomposites were enhanced by 10.2-20 and 3.3-18.4%, respectively, as compared to the ER/u-GNP composites. Moreover, the nanocomposites prepared with PGMA-GNP had better water sorption and wettability properties than those prepared with u-GNP, but lower electrical conductivity. The corrosion test results showed that the addition of GNPs to epoxy effectively improved the corrosion resistance of the epoxy composites in high salinity, basic, and acidic environments.