Sustainable and CO2-rich electrospun nonwovens with enhanced mechanical properties obtained from isocyanate-free aliphatic-aromatic poly(carbonate-urethane)s

Abstract

Meeting the criteria of performance and biocompatibility poses a significant challenge in developing polymeric nonwovens for biomedical and filtration purposes. Although non-isocyanate poly(carbonate-urethane)s (NIPCUs) made by transurethane polycondensation are emerging as non-toxic alternatives to isocyanate-based polyurethanes, their fibrous processing is scarce. Therefore, our work focused on preparing electrospun nonwovens from sustainable NIPCUs with an architecture tailored for high mechanical strength. Combining aromatic 4,4′-diphenylmethane bis(hydroxyalkyl carbamate) hard segments and soft oligocarbonate segments imparted strength and flexibility, while incorporating up to 29 wt % of CO₂ into the structure of the NIPCUs. Scanning electron microscopy showed that adjusted electrospinning parameters produced uniform, submicron fibers without defects. FT-IR and NMR spectroscopy confirmed their unchanged composition and molar mass (20–25 kg mol⁻¹) compared to the unprocessed NIPCUs. Differential scanning calorimetry and dynamic mechanical thermal analysis showed that the macromolecular arrangement induced during electrospinning was strongly dependent on the architecture of the polymer. The mechanical performance of the nonwovens, reaching tensile strength above 5 MPa and elongation at break up to 250 %, correlated to their morphological differences. Thus, appropriate modification of the structure and morphology of the NIPCU nonwovens allowed the production of CO₂-rich submicron fibers with high toughness and flexibility.