Utilizing poly(4‐hydroxybutyrate) as a reinforcing additive to produce high‐performance and biodegradable PBAT blends tailored for foaming applications

Abstract Poly(butylene‐adipate‐co‐terephthalate) (PBAT) is recognized for its advantages as a biodegradable thermoplastic polyester. However, its application is often limited due to low strength and poor processability. In contrast, poly(4‐hydroxybutyrate) (P4HB) emerges as a fully biodegradable polyester characterized by high strength, excellent toughness, and facile processing. In this study, P4HB was employed to reinforce PBAT, and glycidyl methacrylate grafted onto poly(4‐hydroxybutyrate) (P4HB‐g‐GMA) was introduced as an effective compatibilizer to address their inherent incompatibility. The study explored the influence of P4HB‐g‐GMA content on the mechanical, thermal, morphological, and rheological properties of the blends. The findings revealed that P4HB‐g‐GMA significantly enhanced the compatibility, mechanical properties, and melt strength of PBAT/P4HB blends. Furthermore, various PBAT/P4HB foams were prepared through a batch foaming process, employing supercritical CO 2 as a physical foaming agent. The volume expansion ratio and cell size of PBAT/P4HB foams increased with higher levels of the compatibilizer.