聚酰亚胺纤维的制备及其结构研究

Preparation and morphology of polyimide fibers

将均苯四甲酸二酐(PMDA)和4,4’-二氨基二苯醚(ODA)在N-甲基吡咯烷酮(NMP)中进行溶液聚合得到聚酰胺酸(PAA)溶液,并用该溶液进行干湿法纺丝得到PAA纤维,分别用化学酰亚胺化法和热酰亚胺化法得到聚酰亚胺(PI)纤维。研究了凝固浴组成和工艺条件对PAA形态结构和纤维性能的影响,以及不同酰亚胺化方法对PI纤维形态结构和性能的影响。结果表明:以甲醇为凝固浴制备的PAA初生纤维,无孔致密,最高拉伸强度和初始模量分别为2．21 cN/dtex和40．73 cN/dtex;采用化学酰亚胺化法制得的PI纤维中存在少许孔洞缺陷,其强度较低,热酰亚胺化法制得的PI纤维无孔致密,其强度和模量分别达到2．83 cN/ dtex和43．4 cN/dtex。

Polyamide acid （PAA） solution was synthesized from pyromellitic dianhydride （PMDA） and 4,4＇-diaminodiphenyl oxide （ODA） with N-methylpyrrolidone （NMP） as a solvent via solution polymerization. PAA fiber was produced from this solution via dry-wet-spinning. Polyimide （PI） fiber was obtained from PAA fiber via chemical imidization method or thermal imidization method. The effects of coagulation bath composition and process conditions on the morphology and properties of PAA fiber were studied. The effects of different imidization methods on the morphology and properties of PI fiber were also studied. The results showed that the as-spun PAA fiber prepared with methanol as coagulation bath had a compact structure without any holes and exhibited the maximal tensile strength and initial modulus of 2.21 cN/dtex and 40.73 cN/dtex, respectively. The PI fiber prepared via chemical imidization method had some hole defects and low strength when the PI fiber prepared via thermal imidization method had a compact structure without any holes and exhibited strength and modulus of 2.83 cN/dtex and 43.4 cN/dtex, respectively.