Interpenetrating Polymer Network PVA/PAA Hydrogels

ABSTRACT A new type of interpenetrating polymer network (IPN) hydrogel based on polyvinyl alcohol (PVA) networking with difuctional monomer, acrylic acid (AA), and its polymer, polyacrylic acid (PAA), generated in situ, were prepared by a non-conventional emulsion method without any added crosslinker, using benzoyl peroxide as initiator and sodium chloride as additive. Structure and bonding in hydrogel due to interpenetrating network were confirmed by infrared spectroscopy. The networking was optimized by variation of reaction parameters such as concentrations of additive, monomer, time, and temperature. The response of the hydrogels with and without NaCl was observed by study of their swelling kinetics, and their apparent activation energies for diffusion (Ed) of water were calculated to be 29.28 and 35.97 J mol−1 K−1 with and without NaCl, respectively. The conductivity and pH were measured at different temperatures. The conductivity decreased largely with temperature whereas pH increased in presence of NaCl. The effect of swelling ratio was studied by variation of AA percentage and the optimal PVA/AA was determined. Biodegradability of the polymeric network was studied by culture media and the surface morphology investigated by scanning electron microscopy (SEM).