Macrokinetics of the Degradation of Polyesterurethanes in Model Biological Media

Abstract

The degradation of samples of thrombo-resistant films of segmented polyesterurethanes (Avcothane® and Biomer®) in water and acidic solutions (acidic phosphates) has been investigated. Avcothane, being the copolymer of a segmented polyurethane with polydimethylsiloxane, degraded in water at a noticeable rate, whereas biomer samples were hydrolytically stable. It was shown that degradation from the surface of the Avcothane samples is controlled by decomposition of the siloxane component, as a result of hydrolysis. The values of the decomposition rate constant obtained allowed the authors to predict the time required for degradation of the surface layers of polyesterurethane (Avcothane), responsible for the thromboresistance.