In the family of polyimide (PI) materials, Upilex-S^® film has been a shining star through the research PI materials due to its appealing merits. Unfortunately, the wholly rigid-rod backbone and easily formed skin-core micromorphology and microvoids of Upilex-S^® type PI lead to the high difficulty in melt- and wet-spinning fabrication. Herein, we propose a facile and scalable method, reaction-spinning, to fabricate the Upilex-S^® type PI fiber, in which the rapid solidification of spinning dope and partial imidization take place simultaneously. Thus, the stability and mechanical strength of as-spun fibers can be improved, and the microvoids in fibers can be greatly reduced in relative to the wet-spun fibers. The resultant Upilex-S^® type PI fiber shows higher tensile strength and modulus than most commercial thermal-oxidative polymeric fibers with an ultrahigh glass transition temperature T_g of 478 °C. Moreover, the WAXS and SAXS results indicate that orthorhombic crystals are formed for Upilex-S^® type PI fiber in the post hot-drawing process. Increasing the hot-drawing temperature results in a continuous crystallization and high orientation of PI chains in amorphous phase and perfects the existing lamellar structure, which make a great contribution to the improved mechanical property.

在家庭的聚酰亚胺（PI）材料的Upilex-S ^®薄膜已经通过研究PI材料一颗耀眼的明星，由于其吸引人的优点。不幸的是，全刚性棒状骨架和容易地形成皮-芯型微观和的Upilex-S微孔^®型PI导致在熔融高难度和湿纺丝制造。在此，我们提出了一种容易的和可扩展的方法，反应纺丝，以制造的Upilex-S ^®型PI纤维，在其同时纺丝原液和部分酰亚胺化走位的快速凝固。因此，可以改善初纺纤维的稳定性和机械强度，并且相对于湿纺纤维，可以大大减少纤维中的微孔。将所得的Upilex-S ^®PI型纤维比大多数商业热氧化聚合物纤维具有更高的拉伸强度和模量，具有478°C的超高玻璃化转变温度T _g。此外，WAXS和SAXS结果表明，斜方晶体形成用于的Upilex-S ^®在后热拉伸处理型PI纤维。热拉伸温度的升高导致非晶相中PI链的连续结晶和高取向，并完善了现有的层状结构，这对改善机械性能做出了巨大贡献。