Swelling behavior of poly(N-vinyl-2-pyrrolidone) and poly(N-vinyl-2-pyrrolidone)/K2S2O8 hydrogels in urea solutions

Abstract

Hydrogels with varying cross‐linking densities and average molecular weights between two consecutive cross‐links were prepared from the binary poly(N‐vinyl‐2‐pyrrolidone)/water and ternary poly(N‐vinyl‐2‐pyrrolidone)/water/K2S2O8 systems by irradiation with γ rays at ambient temperature. Both hydrogel systems were employed for diffusion and swelling experiments in various urea solutions at room temperature. Diffusion of urea solutions into hydrogels has been found to be of the non‐Fickian type, except for the samples of PVP/K2S2O8 hydrogels irradiated at higher doses in dilute urea solutions. The percent swelling, equilibrium swelling, initial rate of swelling, swelling rate constant, equilibrium water/urea content, and diffusion constant values were evaluated for PVP and PVP/K2S2O8 hydrogel systems at two different urea concentrations. With regard to swelling data, it was determined that the dilute urea solution can penetrate much more effectively into the PVP/K2S2O8 hydrogel system. © 2000 John Wiley & Sons, Inc. Adv Polym Techn 19: 210–217, 2000

The effect of processing design and the stabilizing effect of nanostructures on the swelling and adsorption properties of polyvinylpyrrolidone macroporous ferrogels obtained through a cryogenic route

“…Figure 7 shows the swelling results for each system after reaching equilibrium in water (48 h of immersion; measurements corresponding to 2 and 24 h of swelling are shown in Table S1). The materials prepared in this study showed good degrees of swelling, in the order of values typically reported in the literature 60–62 …”

“…The materials prepared in this study showed good degrees of swelling, in the order of values typically reported in the literature. [60][61][62] Some results deserve to be remarked. First, the increase in PVP concentration does not influence (within the limits of error) the degree of swelling of the gels, with both G8 and G16 reaching values of approximately 1100%.…”