含嘧啶杂环聚酰亚胺纤维的湿法纺丝成形及结构性能

以2,5-二(4-氨基苯基)嘧啶与3,3',4,4'-联苯二酐聚合得到高分子质量的聚酰胺酸溶液,采用"两步法"湿法纺丝制备聚酰亚胺纤维,研究了凝固浴组成对纤维成形形貌的影响以及热亚胺化、热牵伸作用对纤维聚集态结构的影响。三元相图与扫描电镜结果显示:过快或过慢的凝固速度均不利于形成规则、致密结构的纤维,以体积比5/5的H2O/DMAc混合溶液为凝固浴时,纤维成形较佳。同步辐射结果显示:热环化、热牵伸均可促进纤维形成更为完善的晶态、取向结构。最终得到聚酰亚胺纤维的最高拉伸强度、模量分别达1.72 GPa与95.1 GPa,此外所得纤维具有优异的耐热稳定性。

Fabrication,Structure and Properties of Polyimide Fiber Containing Pyrimidine Moiety Prepared by Wet-Spinning Method

An aromatic poly(amic acid) dope was synthesized from 2,5-bis(4-aminophenyl)-pyrimidine and3,3',4,4'-biphenyltetracarboxylic dianhydride. The corresponding polyimide fiber was fabricated via a two-step wet-spinning method. The morphology and aggregation structure of the fiber were investigated by scan-ning electron microscope(SEM) and 2 D-wide angle X-ray diffraction(2 D-WAXD) technology. The SEM re-sults indicate that the as-spun precursor fiber with a regular and dense morphology is obtained in the H2 O/DMAc solution at a volume ratio of 5/5. 2 D-WAXD data reveales that the better-define crystal structure for-mation is mainly induced by the effects of thermal and thermal stretching. The obtained polyimide fibershows excellent thermal oxidative stability and the optimal tensile strength and modulus reaches to 1.72 GPa and 95.1 GPa, respectively.