Aromatic polyimide fibers having an enhanced mechanical strength are produced by a process comprising the steps of: preparing a spinning dope solution of at least one aromatic polyimide having 90 molar %or more of a recurring unit of the formula (I):
wherein R is divalent aromatic radical, in a phenolic solvent; converting the dope solution into at least one filamentary stream thereof; solidifying the filamentary dope solution stream by removing the solvent therefrom to provide at least one undrawn filament, and; drawing the undrawn filament at a temperature of 20 to 600°C at a draw ratio of 1.5 to 5.0.
具有增强机械强度的芳香族聚
酰亚胺纤维的生产工艺包括以下步骤:在
酚醛溶剂中制备至少一种芳香族聚
酰亚胺的纺丝掺合料溶液,该掺合料溶液具有90摩尔%或更多的式(I)
重复单元:
其中 R 为二价芳香基,在
酚类溶剂中;将涂料溶液转化为至少一种长丝流;通过去除溶剂使长丝涂料溶液固化,以提供至少一种未牵伸长丝,以及;在 20 至 600°C 的温度下以 1.5 至 5.0 的牵伸比牵伸未牵伸长丝。