(The) transport phenomena of a series of amides through the copolymer hydrogel membranes

Abstract

2-Hydroxy ethyl methacrylate (HEMA) and N-vinyl-2-pyrrolidone (VP) were copolymerized in the presence of the solvent and the crosslinker tetraethyleneglycol dimethacrylate (TEGDMA). Hydrogel membranes were prepared by copolymerizing the monomers as a thin transparent film. By changing the monomer composition and the crosslinker content, different membranes were synthesized. Using these membranes, relative permeabilities ($U_{re}$) and distribution coefficients ($K_D$) for amides including urea were measured. The water contents in membrane were also measured. From $U_{re}$ and $K_D$, diffusivities(D) were calculated. On the basis of solute-membrane matrix interaction, the diffusion data were discussed. With increasing the volume fraction of VP in the comonomer, $U_{re}$, D, and $K_D$ increased monotonously, since VP is more hydrophilic than HEMA. With increasing the crosslinker content, $U_{re}$, D, and $K_D$ decreased. In membranes of low crosslinker content, the molecular size was the controlling factor in $U_{re}$ and D. But with increasing the crosslinker content, the hydrogen bonding effect between the solutes and the polymer matrix is more important than the effect of the molecular size.