Facile synthesis of a degradable gel by radical copolymerization of vinyl sorbate and molecular oxygen

摘要

A new kind of degradable gel was prepared by radical copolymerization of vinyl sorbate (VS) with molecular oxygen. A soluble and linear copolymer was produced at the initial stage of the polymerization and the ratio of the gel fraction was rapidly increased in the process of polymerization. An analysis of the polymerization by near infrared (NIR) spectroscopy strongly suggests that the conjugated diene group is much more reactive than the vinyl ester group. The degradation of an insoluble part (VS-gel) was investigated by thermogravimetric (TG) and differential thermal analyses (DTA). Thermal degradation exothermically occurred around 110degreesC. The weight loss of the gel was simultaneously observed. The VS-gels obtained from polymerizations at various monomer concentrations had different physical properties, but similar degradation properties. The higher the VS monomer concentration in the feed, the lower the swelling ratio of the obtained gels due to an increase in a crosslinking density. The degradation of the VS-gel under several stimuli other than heating was also investigated.