# Zinc‐Catalysed Depolymerization of Poly(Butylene Succinate) and Poly(Butylene Adipate‐co‐Terephthalate) and Enhanced Degradation of Catalyst‐Polymer Composite Films

## TL;DR

A zinc catalyst efficiently breaks down two biodegradable plastics, even when embedded in the material, speeding up their degradation in methanol and water.

## Contribution

A zinc catalyst enables rapid depolymerization and enhanced degradation of bio-derived polyesters when embedded in polymer films.

## Key findings

- Zinc-catalyzed methanolysis of PBS achieved 98% conversion and 62% dimethyl succinate yield in 48 hours.
- Embedding the catalyst in polymer films caused significant mass loss and molecular weight reduction in methanol and water.
- Solvent-free methanolysis of PBS and PBAT reached high conversion in just 1 hour at elevated temperatures.

## Abstract

The depolymerization of poly(butylene succinate) (PBS) and poly(butylene adipate‐co‐terephthalate) (PBAT) with a highly active zinc catalyst was investigated. The methanolysis of PBS in solution was optimised by varying temperature, catalyst loading, and methanol equivalents, giving a maximum conversion of 98% after 48 h with a dimethyl succinate yield of 62%. Solvent‐free methanolysis of PBS and PBAT was shown to reach high conversion after 1 h, although increased temperature was required (100–130°C). When the catalyst was embedded into thin films of PBS and PBAT, a significant loss of mass and a reduction in molecular weight was observed after incubation at 50°C in methanol, comparing favorably with samples of pure polymer. Some increase in degradation activity was also observed in deionized water. This work demonstrates the application of common chemical recycling techniques to increasingly relevant bio‐derived polyesters as well as the potential for embedded zinc catalysts to promote degradation.

Biodegradable polymers are a crucial part of a sustainable future with plastics. The depolymerization of two prominent examples, poly(butylene succinate) and poly(butylene adipate‐co‐terephthalate), is reported with a highly active zinc catalyst. This includes rapid depolymerization in neat methanol. The catalyst was also embedded into polymer films and incubated in water or methanol, showing significant mass loss and reduction in molecular weight compared to a pure control sample.© 2026 WILEY‐VCH GmbH