Preparation of Graphene oxide/Poly(acrylic acid) Hydrogel by γ-ray Pre-irradiation

Abstract

The graphene oxide/poly(acrylic acid) hybrid hydrogel was synthesized using a γ-ray pre-irradiation technique. The γ-ray radiation was used for modifying the functional groups of graphene oxide to peroxides. The changes of functional groups and structural deformation of graphene oxide by γ-ray radiation were investigated in detail. This modified graphene oxide (GO) was utilized as initiator for polymerizing acrylic acid monomer to polymeric hydrogel. Radical species are generated from the thermal decomposition of peroxides of the modified GO and they initiate the radical polymerization of acrylic acid monomer. The variation of interior morphology at different reaction period was observed by scanning electron microscopy. The chemical bond between graphene oxide and poly(acrylic acid) framework was investigated with FT-IR spectroscopy. The analysis of mechanical and thermal properties confirmed the role of graphene oxide in the hydrogel as reinforcing agent. The swelling ability of hydrogel, which is originated from electrostatic repulsion of deprotonated poly(acrylic acid) chains in a basic condition, was measured and Scanning electron microscope image of the swollen state was obtained. In this study, a variety of advantages could be obtained by using γ-ray pre-irradiation such as mild and simple synthetic procedure, and modified GO substitutes conventional initiator and cross-linker so that Well-defined hydrogel network was obtained without further additives.