Improving foaming behavior of poly(L‐lactide‐co‐ε‐caprolactone) by blending with polyhydroxyalkanoates

Abstract Poly(L‐lactide‐co‐ε‐caprolactone) (PLCL) has garnered significant attention in the biomedical field due to its excellent properties, including good biocompatibility, with mechanical characteristics similar to those of human soft tissues. However, PLCL is a linear amorphous polymer with low melt strength, which leads to foam shrinkage and collapse, and low open‐cell content, thus limiting its potential applications in the human body. To address this, polyhydroxyalkanoates (PHA) were blended with PLCL at varying ratios (0–20 wt%) to enhance foamability via supercritical CO 2 . The addition of PHA increased melt strength, reduced cell size (from 103 μm in pure PLCL to 5.6 μm in PLCL/PHA‐20), and improved cell density (from 6.2 × 10 4 to 3.2 × 10 9 cell/cm 3 ). The PLCL/PHA‐15 blend exhibited optimal foaming performance, achieving a 6.6‐fold expansion ratio and 82% open‐cell content at 85°C/13.8 MPa. Enhanced compression recovery (permanent deformation <10%) and tunable mechanical properties (elastic modulus: 2.1–6.3 MPa) were achieved. This work demonstrates the potential of PLCL/PHA blends for biomedical scaffolds requiring tailored porosity and elasticity. Highlights PHA improves the melt strength and tensile strength of the PLCL matrix. PLCL/PHA foam cell size decreases markedly; density increases drastically. PHA serves as heterogeneous nucleation sites, promoting open‐cell structures.