Flexible preparation of PA6-based thermoplastic elastomer filaments with enhanced elasticity, melt spinnability and transparency enabled by high-molecular-weight soft segments

The melt polymerization of polyamide 6 (PA6)-based thermoplastic elastomers with high-content and high-molecular-weight soft segments (HS-TPAEs) has posed a long-standing challenge, rendering them unsuitable for filament presentation in textiles. To address this issue, a “3-step” melt polymerization method was employed to enable a more flexible synthesis of HS-TPAEs. The HS-TPAEs prepared using this method exhibited a well-defined microphase-separated morphology, and their melting temperature (T_m ∼ 185 °C) was found to be 25 °C higher than that of Spandex®, which is the most widely used elastic filament for fabrics. Furthermore, enhanced elasticity, melt spinnability and transparency enabled by the high-molecular-weight soft segments were demonstrated for HS-TPAEs with 55 wt% soft segments (HS-TPAE-55). Notably, the filaments produced from molten HS-TPAE-55 exhibited thermo-mechanical performance comparable to that of Spandex®. In summary, this research provides a foundation for the industrial-scale production of innovative elastic filaments through melt spinning in the textile industry.