Radiation synthesis and characterization of N-vinyl-2-pyrrolidone/N-allylthiourea hydrogels and their use in the adsorption of invertase

N-Vinyl-2-pyrrolidone/N-allylthiourea (VP/ATU) copolymeric hydrogels were prepared by gamma-irradiating ternary mixtures of VP/ATU/water. The influence of the ATU on the gelation of VP, on the network structure and on the adsorption of invertase was investigated. VP/ATU copolymeric hydrogels were found to swell in the range of 950-2500%. The water diffusion to the hydrogels is a non-Fickian type diffusion and the diffusion coefficients varied from 15.4.10(-8) to 1.5.10(-8) m(2) s(-1). The adsorption capacity of the hydrogels was found to increase from 8.0 to 380.0 mu g invertase/g dry gel with increasing amount of ATU, and loss in activity with adsorption is approximately threefold.