Non-covalently surface modification of graphene oxide nanosheets and its role in the enhancement of the epoxy-based coatings' physical properties

The surface of graphene oxide (GO) nanosheets was modified by a complex of benzimidazole (BI) molecules-cerium (III) ions and analyzed by UV-vis, SEM/EDS, and Raman methods. The improvement in the epoxy-based coatings' mechanical characteristics after the inclusion of the modified and unmodified GO sheets was studied by tensile (stress-strain plots) and dynamic mechanical thermal analysis (DMTA) tests. Furthermore, the morphology of the fractured-surface was analyzed by cross-section SEM analysis. The modified GO (MGO) nanoparticle dispersion quality in the coating structure was examined by X-ray diffraction analysis (XRD). The XRD test results depicted that the modification of GO by BI-Ce complex, BI, and cerium (III) led to the nanosheets dispersion improvement in the polymer matrix under study. The tensile test results evidenced that the stress at break, Young's modulus, energy at the break, and elongation at break values increased by 99.6 %, 40.3 %, 133.4 %, and 446.4 %, respectively by addition of MGO nanoparticles. Also, the DMTA results showed that the T-g and E' values increased by about 13 % and 102 %, respectively, after inclusion of MGO nanoparticles in the nanocomposite.