Pyromellitic dianhydride (PMDA)/4,4′-oxidianiline (ODA) polyimide (PI) orientation models with different draft ratios were established to reveal the macromolecular structural evolution of PI chains during large-ratio uniaxial fiber orientation process. The high consistency between experimental data and modelling results, in terms of mechanical properties and XRD patterns, demonstrates the rationality of the orientation models. The simulation results indicated that the PI chains became stretched from entanglement and arranged along the draft direction in the fiber drafting process, and chain orientation observed in PMDA/ODA-based PI fibers during drafting was mainly caused by the change of CCOC torsion distribution in the ODA units.

建立了具有不同牵伸比的均苯四甲酸二酐（PMDA）/ 4,4'-氧化苯胺（ODA）聚酰亚胺（PI）取向模型，以揭示大比例单轴纤维取向过程中PI链的大分子结构演变。在力学性能和XRD图案方面，实验数据与建模结果之间的高度一致性证明了定向模型的合理性。仿真结果表明，在纤维牵伸过程中，PI链从缠结开始拉伸并沿牵伸方向排列，牵伸过程中在PMDA / ODA基PI纤维中观察到的链取向主要是由C C O C扭转的变化引起的。在官方发展援助单位中分配。