Abstract Poly( l -lactic acid) (PLLA) twisted nanofiber yarn (TNFY) was continuously prepared using a CO2-laser supersonic multi-drawing apparatus equipped with a twister-winder that offers independent control of winding speed (SW) and twisting speed (ST). TNFYs with various twist numbers (nT), twist angles, and bulk densities were produced by changing SW and ST. TNFYs with a wide nT range of 395–1276 T m−1 were obtained. Furthermore, the mechanical properties of the obtained TNFYs depended upon the degree of twist. The maximum Young’s modulus was 3.06 cN dtex−1 at ST = 300 T min−1 and SW = 0.440 m min−1, and the maximum tensile strength was 0.36 cN dtex−1 at ST = 365 T min−1 and SW = 0.440 m min−1. The Young’s modulus had a maximum value at optimum obliquity because the high twist reduced the contribution of fiber strength to the yarn hardness due to fiber obliquity in the yarn. The tensile strength increased with increasing ST because the frictional forces among the NFs were increased by twisting at higher ST.

中文翻译：

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二氧化碳激光超音速多次拉伸制备聚左旋乳酸纳米纤维捻线

摘要 聚（l-乳酸）（PLLA）加捻纳米纤维纱（TNFY）是使用配备有可独立控制卷绕速度（SW）和捻度速度的加捻机的CO2激光超声多次拉伸装置连续制备的。英石）。通过改变 SW 和 ST 产生具有不同扭曲数 (nT)、扭曲角和体积密度的 TNFY。获得了具有 395-1276 T m-1 宽 nT 范围的 TNFY。此外，获得的 TNFY 的机械性能取决于扭曲程度。最大杨氏模量在 ST = 300 T min-1 和 SW = 0.440 m min-1 时为 3.06 cN dtex-1，在 ST = 365 T min-1 和 SW = 0.440 时最大拉伸强度为 0.36 cN dtex-1米分钟-1。由于纱线中的纤维倾斜，高捻度降低了纤维强度对纱线硬度的贡献，因此杨氏模量在最佳倾斜度处具有最大值。拉伸强度随着 ST 的增加而增加，因为在较高的 ST 下扭曲会增加 NF 之间的摩擦力。