Graphene Oxide/Silicon-containing Cycloaliphatic Epoxy Resin Nanocomposites:Preparation And Properties

Much of the excitement around graphene, a one-atom thick layer of sp2-hybridized carbon atoms, is related to its unique authentic two-dimensional structure which leads to outstanding properties. As a precursor in large-scale synthesis of high-quality graphene and a momentous graphene-derived material, graphene oxide(GO) is also an excellent nano-filler owing to a nice dispersity in epoxide monomer, a high reactivity with epoxide system during curing and properties improvement around multiple fields to the polymer matrix. Basing on the study of recently reported cycloaliphatic epoxy resin, a silicon-containing graphene oxide/cycloaliphatic epoxy resin with novel structure has been synthesized. The structure and properties have been characterized and systematically studied.(1) GO is synthesized by ultra-sonic exfoliation of graphite oxide manufactured by Hummers oxidation. FTIR spectrum indicates hydroxyl, epoxy and carboxyl groups are contained in the GO, XPS spectrum further confirms the C/O ratio of3/1. Raman spectrum ensure the ratio of sp2and sp3in GO layers, proving an appropriate level of oxidation. Resulting from WAXD spectrum, most GO sheets maintain single-layer structure. At the same time, SEM images have been employed to the observation of micro-structure of GO. Lateral size of the GO sheet is up to several microns, and the surface shows wrinkled and silk-like characteristic which is identical to graphene feature. Above conclusions well support the Lerf GO-model. TGA test shows the thermo degradation temperature of GO is around200℃.(2) Ultra-sonic approach is used in incorporating GO into silicon-containing cycloaliphatic epoxide monomer. With the assist of anhydride HMPA and2-ethyl-4-methylimid-azole EMI (curing agent and curing accelerate agent respectively), silicon-containing graphene oxide/cycloaliphatic epoxy resin nanocomposites(GO/SiEP) have been manufactured by in-suit polymerization. WAXD, FTIR, SEM and TEM are used in characterizing dispersity of graphene oxide in epoxy resin. Results show a homogeneous dispersion of GO in polymer matrix and indicate GO sheets have blocked into the cross-linking network of polymer matrix.(3) TGA, DMA, insulating property test and dielectric constant test of the GO/SiEP have been employed. Results show that thermo stability of GO/SiEP has been significantly improved, thermo degradation rate has been decreased50%and char residual has been increase to30%utmost. Glass-transition temperature of GO/SiEP increase during low loading of GO and decrease when GO loading continuous rising. Compared with neat SiEP, electrical resistivity of GO/SiEP is not affected. Dielectric permittivity of GO/SiEP has been utmost increase from5to54, makes the GO/SiEP a huge potential application in embedded capacitor.