Modification of graphene with organic/inorganic silicon-based materials and its reinforcement on the UV-curing polyurethane composite coatings

Functionalized graphene (FGO) was prepared through the sol-gel method and thiol-ene reactions. FGO was subsequently incorporated into polyurethane (PUA) through UV-curing process. The structural and morphological features of FGO/PUA composite coatings were characterized by transmission electron microscopy (TEM) as well as scanning electron microscope (SEM). The TEM and SEM results show that FGO nanosheets are homogeneous dispersed in the PUA matrix and form the strong interfacial interaction with PUA matrix due to the formation of chemical reaction between FGO and PUA matrix. Moreover, the incorporation of FGO could effectively enhance the thermal, flame retardant, and mechanical properties of composite coatings. The thermal stability of the PUA composite coatings with only 0.1 wt% FGO was increased by 18 degrees C. Meanwhile, the incorporation of FGO could also reduce the peak heat release rate (pHRR) of PUA resins. Compared with pure PUA, the storage modulus and tensile strength of the composite coatings with 0.5 wt% FGO were also improved by 9% and 82%, respectively. By contrast, rGO/PUA composite coatings could not form homogeneous dispersion and exhibit significant accumulations. Consequently, the covalent modification of graphene presented herein will provide a feasible and effective approach to the modification of graphene and the obtained FGO could impart PUA with high performance. POLYM. COMPOS., 39:746-754, 2018. (c) 2016 Society of Plastics Engineers