Abstract
To precisely identify the effect of molecular parameters such as stereoregularity, degree of saponification (DS), and molecular weight of syndiotacticity-rich poly(vinyl alcohol) (s-PVA) hydrogels prepared by freezing-thawing on the release behaviour of bovine serum albumin (BSA), we prepared various (s-PVA)s by copolymerization of vinyl pivalate and vinyl acetate and subsequent saponification. A series of experiments showed that molecular and processing parameters of s-PVA hydrogel had a significant influence on the BSA release behaviour of the hydrogel. That is, both the release rate and the amount of residual BSA decreased with increasing syndiotacticity of PVA. In the case of s-PVA hydrogels with higher DS and higher molecular weight, the BSA release was suppressed. The rate of BSA release increased with an increase in the release temperature. In addition, the release rate of s-PVA hydrogel made with one freezing-thawing cycle was higher than with three cycles. It was confirmed conclusively that s-PVA hydrogels having various kinds of release behaviour can be prepared by controlling molecular and processing parameters of PVA, for various biomedical applications.