Biodegradability of Lactide-Caprolactone Macromonomers in Wastewater

A desire to develop biorenewable materials has led to lactide- caprolactone copolymers being used in adhesive, medical, and pharmaceutical products. Use of this alternative material may diminish human impact on the environment and create products that are biocompatible. One advantage of these materials compared with other typical petroleum-based polymers is that they are easily degraded by microorganisms. In this study, the biodegradation of representative lactide-caprolactone macromonomers and an acrylic pressure sensitive adhesive incorporating these macromonomers was followed by a respirometric method using a consortium of microorganisms found in a typical wastewater treatment facility. The weight loss data of lactide- caprolactone macromonomers showed that the lowest molecular weight macromonomers with a high percentage of lactide had the greatest weight loss, which could have been caused by the greater number of ester linkages. Proton nuclear magnetic resonance data showed that for lower molecular weight copolymers, there was a preferential loss of caprolactone. Promisingly, testing of the full acrylic adhesives showed that they were easily degraded and thus provided a route to more environmentally friendly adhesive products.