BPDA/PPD/OTOL聚酰亚胺纤维的力学性能、形貌和结构

Mechanical Property,Morphology and Structure of BPDA/PPD/OTOL Polyimide Fibers

在3,3',4,4'-联苯四酸二酐(BPDA)和对苯二胺(PPD)体系中引入3,3'-二甲基联苯胺(OTOL),显著改善了纤维的力学性能。当n(PPD)∶n(OTOL)=70∶30时,纤维的拉伸强度可达到改性前的2倍,其拉伸强度和拉伸模量分别为1.50和80 GPa。SEM照片显示了纤维的断面为圆形且没有孔穴,也没有明显的"皮芯"结构和原纤结构。WAXD和SAXS分析表明,纤维的轴向堆积和分子链取向在热牵伸过程中得到改善。

After incorporating o-tolidine（OTOL） into 3,3＇ ,4,4＇-biphenyhetracarboxylic dianhydride（BPDA） and p-phenylenediamine （PPD） backbone, the mechanical properties of fibers were dramatically improved. The strength and modulus of BPDA/PPD/OTOL polyimide （PI） fiber （diamine molar ratio of n,（ PPD ） ： n（OTOL） =70：30） attained 1.50 and 80 GPa, respectively, which were two times of the tenacity of BPDA/ PPD PI fibers. SEM pictures showed that the cross-sections of the fibers at each stage were circular and voids free, and also .no obvious ＂skin-core＂ and microfibrillar structure and wide/small angle X-ray scattering （WAXD/SAXS） experiments indicated that the longitudinal stacks and the molecular orientation of PI fiber were improved in the heat-drawn process.