NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, vol.208, pp.242-246, 2003 (SCI-Expanded)
In the present work ternary systems composed of dimethylaminoethyl methacrylate/water/ethyleneglycol dimethacrylate (DMAEMA/water/EGDMA) were prepared at varying compositions and irradiated with gamma rays up to 4 kGy. The hydrogels thus prepared were characterized with respect to their swelling properties, network structures and mechanical properties by compression tests. Molecular weight between cross-links () and effective cross-linking density (νe) of DMAEMA/EGDMA hydrogels were calculated from swelling and shear modulus data obtained from compression tests. The results have shown that simple compression analyses and equations derived from Phantom network theory can be used for the determination of effective cross-link density of hydrogels without needing some polymer-solvent based parameters as in the case of swelling based determinations. By using theoretically and experimentally calculated cross-link densities, the cross-linking enhancement efficiency of EGDMA was calculated. It has been found that added EGDMA can facilitate the cross-linking reactions effectively during irradiation and improves the cross-linking efficiency approximately eightfold when used only 0.05% concentration in the initial monomer mixture.