Elution of polymers from physically cross-linked poly(vinyl alcohol) gels

Elution of polymers from physically cross-linked poly(vinyl alcohol) (PVA) gel in its swollen state was investigated by measuring quantitatively the total carbon in the outer water using a Total Organic Carbon (TOC) analyzer. The dried samples, prepared by a cast-drying method, were immersed in pure water under different conditions. As a result, the elution was detected, and it gradually stopped in a limited amount of water. On the other hand, the polymer was successively released by exchanging the outer water repeatedly at long intervals (more than 21 h), which was suppressed by adding a drying treatment at each water exchange. Effects of the degree of polymerization of PVA on the elution ratio were also presented.