New HydrogelsBased on Substituted Anhydride ModifiedCollagen and 2-Hydroxyethyl Methacrylate. Synthesis and Characterization.

Semi-interpenetrated networks wereobtained by free radical polymerization/cross-linkingof substituted anhydride modified collagen with 2-hydroxyethyl methacrylate(HEMA) in the presence of ammonium persulfate (APS) and N,N,N′,N′-tetramethyl ethylene diamine (TEMED). Substituted anhydridemodified collagens, porous materials with vinyl groups, have beenpreviously synthesized by reaction of soluble collagen with dimethylmaleic anhydride (DMA) or citraconic anhydride (CTA). The structureand physicochemical properties of the obtained hydrogels were investigatedby Fourier transform infrared spectroscopy, scanning electron microscopy(SEM), and water retention studies. Thermal properties of substitutedanhydride modified collagen and their corresponding hydrogels havebeen investigated by differential scanning calorimetry (DSC) in driedand hydrated states. The denaturation temperature (Td), denaturation enthalpy, and glass transition temperature(Tg) have been determined, and they werefound to be dependent on chemical composition, thermal history, andmoisture content. The water states (free or bonded) in the hydratedsamples were correlated with their swelling degree. [ABSTRACT FROM AUTHOR]