Green and sono synthetic approach for direct-functionalization of reduced graphene oxide with poly(styrene-alt-maleic anhydride) by Diels Alder click reaction

The green ultrasound assisted Diels-Alder (DA) click reaction was utilized to the direct functionalization of reduced graphene oxide (rGO) with poly(styrene-alt-maleic anhydride) (PSMA) for the first time. PSMA derivatives having pendant furfuryl groups (PSMF) were synthesized by the ring-opening reaction of furfuryl amine and succinic anhydride moieties of PSMA backbones, and then the pendant furfuryl groups were used to grafting PSMF onto the surface of rGO through the DA cycloaddition. The direct and indirect evidences of covalent functionalization of PSMF onto rGO hybrids were obtained by means of Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The grafted PSMF was calculated to be 13 wt% in 4 h of reaction with sonication, while that was 8 wt% after 48 h with only stirring at the same condition, indicating that the reaction rate under ultrasound irradiation was much faster than the conventional method. The rGO-PSMF hybrid showed highly stable dispersion in water owing to PSMF as expected.