Degradation Behavior of the Hydrogel Poly(vinyl alcohol)-graft-Poly[(rac-lactide)-co-Glycolide)] under Different Conditions

Summary: The hydrogel poly(vinyl alcohol)-graft-poly(rac-lactide)-co-glycolide)] PVA-g-P(LGA)], containing nine ester groups in the polyester grafts (lactide:glycolide ratio 50:50) grafted onto PVA to an extent of 13%, and crosslinked via terminal acrylate groups was subjected to degradation experiments in phosphate buffer solution (pH 7.4) at room temperature and at 37 °C during 8 weeks. In the course of degradation, the properties of the hydrogel change as a result of the decrease of the polyester content. The increased temperature has a significant influence on the degradation rate but its amount varies with the methods applied. Thus, a large drop of the elastic modulus takes place in samples degraded at 37 °C with time and relative to RT. Thermal and IR analysis show changes while the initial difference between two sets of samples in contact angle is reduced with time.