When fabricated by thermal exfoliation, graphene can be covalently functionalized more easily by applying a direct ring-opening reaction between the residual epoxide functional groups on the graphene and the amine-bearing molecules. Investigation by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) all confirm that these molecules were covalently grafted to the surface of graphene. The resulting dispersion in an organic solvent demonstrated a long-term homogeneous stability of the products. Furthermore, comparison with traditional free radical functionalization shows the extent of the defects characterized by TEM and Raman spectroscopy and reveals that direct functionalization enables graphene to be covalently functionalized on the surface without causing any further damage to the surface structure. Thermogravmetric analysis (TGA) shows that the nondestroyed graphene structure provides greater thermal stability not only for the grafted molecules but also, more importantly, for the graphene itself, compared to the free-radical grafting method.
Polypropylene was successfully covalently grafted onto the surface of thermally reduced graphite oxide (PP-g-TRGO) by taking advantage of the "residual oxygen-containing functional groups" and the "grafting to" method. The PP-g-TRGO obtained showed an improved compatibility, and interfacial interaction, with an isotactic PP (iPP) matrix. The iPP/PP-g-TRGO nanocomposite exhibited a dramatically improved thermal stability compared to that of neat iPP even at low loadings.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.