Mechanistic Aspects of Polyurethane Biodeterioration

Abstract

Polyester-based polyurethanes are particularly susceptible to bio- degradation by a wide range of micro-organisms. Many of them produce extracellular esterases, which have been used to study the degradation of model polyurethanes. The polymer containing only urethane links, and the polymers containing ester and urethane links were degraded, indicating that both are susceptible to enzymatic hydrolysis. A polyester-based polyurethane containing an effective biocide was still degraded by the isolated enzyme preparations. Partial characterisation of the crude esterase preparations from four micro- fungi by gel permeation chromatography has indicated possible differences in the mechanism of polyurethane degradation by different micro-organisms. Analysis of the MW distributions of a polyester- based polyurethane before and after microbial degradation showed that bulk MW, although reduced, is not unduly affected by the action of micro-organisms, but polydispersity of the polymer increases.