The textile industry faces an urgent need for sustainable alternatives to petroleum-derived fibers, with bio-based and biodegradable polymers emerging as promising candidates. In this work, we demonstrate the successful melt-spinning of polyhydroxyalkanoate (PHA) monofilaments, specifically P(3HB)/P(3HB-co-4HB), into woven and knitted textiles using standard industrial machinery. This is relevant, as PHA processing into textile-grade fibers has remained a major challenge due to its thermal sensitivity and mechanical limitations.

The resulting monofilaments exhibited tensile strengths of ~138 MPa and elongation at break of ~55%, with crystallinity around 30%. Mechanical testing under cyclic loading revealed pronounced hysteresis during the first cycle, which diminished in subsequent cycles; importantly, a short relaxation period of 120 s was sufficient to reset conformational changes, demonstrating recoverability under repeated stress. Beta tricalcium phosphate (ß-TCP) particles were incorporated during melt-spinning. While this reduced tensile strength, it significantly improved thermal stability, thereby expanding the processability window for melt spinning.