Optimization of Bio-Based Polyurethane Elastic Nanofibrous Membrane via Electrospinning for Waterproof and Breathable Applications

Bio-based polyurethane (BPU) offers excellent biocompatibility and outstanding elasticity, providing vast potential for the development of next-generation waterproof and breathable materials. However, achieving stable and uniform electrospinning of BPU remains a significant challenge. Herein, BPU with superior electrospinning performance was synthesized using poly(butylene sebacate), poly(trimethylene ether glycol), ethylene glycol, and methylene diphenyl diisocyanate (MDI) as raw materials. BPU nanofibrous membranes were successfully fabricated using solutions of varying concentrations (12 wt%, 16 wt%, 20 wt%, and 24 wt%), and their morphology, mechanical properties, hydrophobicity, and breathability were systematically analyzed. The nanofibrous membrane prepared with 20 wt% BPU solution exhibited optimal fiber morphology and mechanical properties, with a tensile strength of 15.6 MPa and an elongation at break of 440.8%. In contrast, lower concentrations (12 wt% and 16 wt%) resulted in insufficient fiber formation, leading to poorer performance, while higher concentrations (24 wt%) significantly reduced fiber uniformity, negatively impacting the overall performance. Additionally, the nanofibrous membrane produced from the 20 wt% BPU solution demonstrated significant hydrophobicity and breathability, with a water contact angle of 133.2°, hydrostatic pressure of 48.2 kPa, and breathability of 12.6 kg·m²·d^-1. These findings suggest that BPU nanofibrous membranes produced via electrospinning hold great potential for application in functional textiles.