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

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.