Synthesis and characterization of noncytotoxic and biodegradable polymethacrylates-grafted chitosan gels.

Poly(methacrylates), namely 2-hydroxy ethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA) and triethylene glycol dimethacrylate (TEGDMA) were grafted onto chitosan by using ceric ammonium nitrate as a redox initiator. Semi-IPN gels of chitosan-graft-poly(HEMA)-graft-poly(EGDMA) and chitosan-graft-poly(HEMA)-graft-poly(TEGDMA) were obtained. The grafting conditions were optimized with respect to monomer concentrations. The products were characterized by TGA, FTIR, XRD and SEM techniques. The solubility of the grafted products in aqueous medium decreased with increasing grafting percentage. The insoluble gels exhibited a highly pH sensitive swelling behaviour. TGA thermograms showed that poly(HEMA)/poly(TEGDMA)-grafted product is much more stable than poly(HEMA)/poly(EGDMA)-grafted product showing that TEGDMA is a more effective crosslinker than EGDMA. According to XRD analysis TEGDMA has a higher tendency to form ordered structures than EGDMA as it is capable of chain folding. The results of cytotoxicity studies revealed that the methacrylate-grafted chitosans were noncytotoxic and good candidates for biomedical applications.