Sustainable Flexible Polyurethane Foams From Marine‐Biodegradable <scp>PHA</scp> and <scp>PCL</scp> ‐Based Polyols: Synthesis, Characterization, and Degradation

ABSTRACT Polyhydroxyalkanoate (PHA) is produced by microorganisms as a CO 2 ‐derived polymer, while polycaprolactone (PCL) is a synthetic semi‐crystalline polyester. Both compounds are known to biodegrade under appropriate conditions in marine and terrestrial environments. In this study, PHA‐ and PCL‐based polyurethane foams were synthesized by reacting these biodegradable polyols (PHA and PCL) with 1,5‐naphthalene diisocyanate via a prepolymer method and subsequent polycondensation at 150°C. Based on FT‐IR spectra, no vibration peak was observed at 2270 cm −1 assigned to free isocyanate groups, indicating the successful formation of polyurethane foams (PUFs). TGA thermograms revealed that the PHA‐ and PCL‐based polymers had good thermal stability, with initial thermal decomposition around 260°C, and the final char residue content increased with higher PHA content in the PUF chain. The PHA content greatly influenced mechanical properties, notably the tensile strength and elongation at break. In accelerated degradation experiments, PUF samples containing PHA showed a higher tendency for degradation under hydrothermal conditions. This indicates that PHA‐containing structures are more susceptible to hydrolytic degradation than those made with only PCL and polyether polyols under the tested conditions. These results suggest that PHA‐based polyurethane has significant potential for various eco‐friendly applications where environmental degradability is desirable.