Abstract
This study adopted free-radical grafting method to modify graphene. And utilize Raman spectroscopy, X-ray photoelectron spectroscopy(XPS) and Fourier transforms infrared spectra(FTIR) to confirm that maleic anhydride molecules are covalently grafted on the surface of graphene. Influence of concentration of carbon nano material on dispersion in polymer composite and influence of modified graphene and unmodified graphene on enhancing interfacial strength of composite would be analyzed in the process of research. According to the the result of TGA analysis that content of maleic anhydride was about 11.02%. Experimental results indicate that the mechanical properties and dispersion of modified graphene are better than those of unmodified graphene composite. The 0.25wt.% modified graphene is said to be the best ratio for enhancing the mechanical properties, improving the tensile strength by 15.43% and the flexural strength by 11.99% compared to epoxy. Scanning electron microscopy was used to observe the failure surface. It can be found that adding modified graphene significantly improves the phenomenon of aggregation. Adding graphene, it is useful to enhance interfacial interaction between matrix and fiber. Experimental results show that both unmodified and modified graphene have positive influence, improving the flexural strength by 2.37% and 16.19%, and the interlaminar shear strength by 34.19% and 36.99%, respectively. In the torsion fatigue test, fatigue life of CFRP with modified graphene can drastically improve two times longer than neat CFRP. Graphene can improve adhesion between fiber and matrix. Moreover, modification can improve graphene dispersion and effectively slow the crack growth rate. Therefore, the mechanical properties of composite material could be enhanced.