Embedding an esterase mimic inside polyesters to realize rapid and complete degradation without compromising their utility

Abstract

Biodegradable plastics are considered as an alternative to commodity non-biodegradable plastics, but they still degrade slowly in the environment. Current strategies to promote their degradation rates often compromise their utility. Here, we enhance the degradation properties of poly(butylene terephthalate/adipate) (PBAT) by embedding an esterase mimic inside the polyester without compromising its processing and mechanical properties. This esterase mimic contains a binuclear zinc site and catalyzes the depolymerization of PBAT with a turnover frequency (TOF) an order of magnitude higher than that of conventional additives (ZnO). With 1 wt% of this enzyme mimic embedded, PBAT exhibits a 3.7-fold enhancement of the degradation rate under composting conditions. Mechanistic investigation indicates that the binuclear zinc binding center polarizes the ester carbonyl group and increases hydroxide uptake, thus leading to faster degradation. This work provides a possible approach to designing polymers that meet requirements of stability during use and fast degradation after use.