Short-chain-length polyhydroxyalkanoates (scl-PHAs) are among the most abundant biologically derived polyesters, offering a renewable, biodegradable alternative to petrochemical plastics. Their appeal lies in their biocompatibility, thermal processability, water resistance, ambient biodegradability, barrier properties and microbial tunability. However, their practical deployment is hindered by inherent brittleness, low melt strength, and poor elongation at break/toughness, limiting their use in flexible or process-intensive applications.
In this work, we present a series of new materials derived from common scl-PHAs that overcome these limitations through targeted crystallinity manipulation and mechanical property enhancement. Using a range of approaches based on either blending, chemical modification, mechanical manipulation, reactive extrusion and/or controlled thermal processing, we have developed a range of tough, flexible scl-PHA-based materials1,2,3. Notably, we have also demonstrated film-blowing capability - a benchmark rarely achieved with unmodified scl-PHAs - thereby opening the door to scalable, high-throughput manufacturing.
Our results show very significant improvements in elongation and toughness, while retaining the desirable biodegradability and renewable origin of the parent polymer. These advances represent a meaningful step toward replacing conventional plastics in flexible packaging and beyond with truly sustainable, circular alternatives.