Free-radical graft polymerization of acrylonitrile on gamma irradiated graphene oxide: Synthesis and characterization

A novel graphene oxide (GO) grafted polyacrylonitrile (PAN) nanohybrid was synthesized via free radical polymerization. An innovative green method has been used to modify the surface of graphene oxide by gamma radiation. GO was gamma irradiated in air at different absorbed doses to enhance the amount of oxidative groups on its surface. The gamma irradiated GO was silanized with vinyltriethoxysilane (VTES) and used as base material to graft acrylonitrile (AN) on its surface. Synthesis parameters were optimized by varying the concentration of monomer, initiator, and surfactant to get maximum grafting of PAN. The percentage of grafting on GO was increased with increase in gamma absorbed dose. Maximum grafting of 850% of PAN was obtained in 100 kGy irradiated GO. Spectroscopic techniques such as FT-IR, Raman and XRD were used to characterize the synthesized nanohybrids. The obtained results confirmed the structural changes during gamma irradiation of GO and successful grafting of PAN onto it. The morphological changes in irradiated GO during silanization and its PAN grafted nanohybrids were studied by field emission scanning electron microscopy (FESEM). Thermal gravimetric analysis (TGA) demonstrated that the thermal stability of GO-g-PAN was decreased with increase in PAN content. The developed nanohybrid can act as a precursor for the development of new materials.