Covalent modification of graphene oxide and applications in polystyrene composites

Abstract

p-Methylstyrene groups were covalently grafted onto graphene oxide (GO) via esterification reactions and confirmed by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis (TGA). The as-prepared functionalized graphene oxide (FGO) exhibits good dispersibility in many organic solvents and monomer such as ethanol, dichloromethane and styrene. The high dispersibility and accessible reactive groups enable the preparation of reduced FGO (FrGO)/cross-linked polystyrene (PS) microsphere nanocomposites with improved thermal and anti-swelling properties. The thermal degradation temperature of the nanocomposites at 1.0 wt% addition increased by 27 °C, while the glass transition temperature improved by 8 °C; the swelling capacity in water and methanol decreased by 66% and 37%, respectively. Such enhanced properties could effectively improve the catalysis performance of nanocomposite-based ion-exchange resins (IERs). The IERs demonstrated high ethylene oxide (EO) conversion and monoethylene glycol (MEG) selectivity in the hydration of EO, even after a long run of 1800 h.