Semi-interpenetrating polymer network hydrogels based on water-soluble N-carboxylethyl chitosan and photopolymerized poly (2-hydroxyethyl methacrylate)

Semi-interpenetrating polymer network (semi-IPN) hydrogels were prepared by UV irradiation of water-soluble N-carboxylethyl chitosan (CECS) and 2-hydroxyethyl methacrylate (HEMA) aqueous solutions in the presence of D-2959 as photoinitiator. Hydrogels were characterized by using scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and X-ray diffractometry (XRD). SEM showed that semi-IPN hydrogels displayed porous surface and therefore had high surface area. XRD indicated that CECS/poly (HEMA) semi-IPN hydrogels had amorphous structure. The thermal stability and equilibrium degree of swelling improved obviously with increase of CECS content. Differential scanning calorimetry (DSC) indicated that free water content increased with increase of CECS content while bonded water content decreased. Cytotoxicity results suggested that semi-IPN hydrogels had good biocompatibility. From these preliminary evaluations, it is possible to conclude that these materials have potential applications in the biomedical field.