Double macromolecules reinforced and toughened GO/epoxy resin composites: The critical role of a rigid-flexible interface

The rigid-flexible transition interface between graphene oxide (GO) and epoxy by double macromolecules using chitosan (CS) and polyethylene glycol diglycidyl ether (EGDE) on GO surface was firstly established, and the effects on dispersion, interfacial and mechanical properties of the composites were investigated. It was proved by FT-IR, Raman, XPS and TEM tests that rigid-flexible macromolecules have been successfully covalently grafted on GO, which could balance the modulus of GO and resin, effectively improving the dispersion in epoxy and forming stronger interface combination. Mechanical tests demonstrated that compared with pure epoxy, the tensile, flexural and impact strength of GO-CS-EGDE (only 0.1 wt%)/epoxy composite increased by 36.2%, 42.9% and 54.3% respectively, and the elongation at break increased by 102.7%. In addition, the stress transfer and strengthening mechanisms of composites have been explored. This work would provide an economic and feasible avenue for the high-performance resin nanocomposites.