Simultaneous Toughening and Strengthening of PHBV/Bio-Based Elastomer Blends Through Reactive Interfacial Compatibilization With Poly(Glycidyl Methacrylate)

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a representative bio-based biodegradable polyester; however, its high crystallinity and brittleness severely restrict its practical applications. To improve its mechanical performance, a thermoplastic copolyester (TPC) elastomer (ET) was used as a toughening agent, and a reactive interfacial compatibilizer—poly(glycidyl methacrylate) (PGMA)—was synthesized to enhance interfacial adhesion between PHBV and the TPC-ET, improving their compatibility. Differential scanning calorimetry and Fourier transform infrared spectroscopy analyses indicated that the epoxy groups of PGMA formed hydrogen bonds with the PHBV and TPC-ET phases, strengthening intermolecular interactions and restricting blend crystallization. Rheological and scanning electron microscopy results revealed that the incorporation of PGMA improved the interfacial bonding, refined the dispersed-phase size, and produced a uniform sea–island morphology. Consequently, the mechanical properties of the PHBV/TPC-ET/PGMA blends considerably improved: the impact strength reached 17.58 kJ m −2 , elongation at break reached 8.23%, and tensile strength reached 27.5 MPa—representing improvements of 270.1%, 69%, and 190.4%, respectively, compared with those of pristine PHBV. The proposed strategy effectively toughens PHBV and increases its application potential in sustainable polymer materials.