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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]

Porous modified collagens with vinylgroups were synthesized byreaction with 2,3-dimethylmaleic anhydride or citraconic anhydride.The structure of modified collagen was assessed by analytical determinationof the amino groups in collagen and spectroscopic methods (Fouriertransform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR)). The amount of protonated amino groups and carboxylicacid moieties of the samples have been determined by potentiometrictitration. The dependence of the viscosity of diluted collagen solutionson the concentration and temperature was followed to determine theirdenaturation transitions. The increased average molecular weight,particle size, and second virial coefficient of modified collagensolutions with respect to the unmodified one proved that modificationtook place. Coupled thermal analyses (TG/DTG/DTA/FT-IR/MS) also indicatedthe collagen modification by increased thermal stability and new volatilecompounds formed during decomposition. The adhesion tests revealedtheir potential application in wound dressing and tissue engineering. [ABSTRACT FROM AUTHOR]