Abstract In situ studies of structure and performance changes in aromatic copolysulfonamide (co-PSA) fibers during stretching at different thermal exposure temperature range from room temperature to 300 °C were carried out using synchrotron small angle X-ray scattering and wide angle X-ray scattering techniques. Results showed that the optimum microstructure and mechanical property of co-PSA fibers were achieved when stretched at 200 °C, the fibril length, fibril misorientation, crystal sizes L002 reached minimum, the long period became maximum at the same strain indicating that lamella and fibrils aligned perfectly, fiber structure compactness at 200 °C. During stretching at RT to 200 °C, at low strain, fibril length, crystal size L002 increased, fibrils oriented along stretching direction, the long period was enlarged; the opposite trend evolution of structure appeared under high strain. But stretching at 300 °C, L002 increased, fibril orientation became poor, the lamellae destroyed easily resulting in the decreasing strength. It can be concluded that co-PSA fibers remain good property under thermal at 200 °C, external force use environment.

中文翻译：

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原位同步加速器SAXS/WAXS在不同热温下芳族共聚磺酰胺纤维拉伸过程中结构和性能的变化

摘要 利用同步加速器小角 X 射线散射和广角 X 射线原位研究了芳族共聚磺酰胺 (co-PSA) 纤维在室温至 300 °C 不同热暴露温度范围内拉伸过程中的结构和性能变化。散射技术。结果表明，co-PSA 纤维在 200 °C 拉伸时获得最佳微观结构和力学性能，原纤维长度、原纤维取向差、晶体尺寸 L002 达到最小值，长周期在相同应变下达到最大值，表明片层和原纤维完美排列，200°C时纤维结构致密。RT至200℃拉伸，低应变时，原纤长度、晶体尺寸L002增大，原纤沿拉伸方向取向，长周期增大；高应变下出现相反的结构演化趋势。但在300°C拉伸，L002增加，原纤维取向变差，薄片容易破坏，导致强度下降。可以得出结论，co-PSA纤维在200°C的热、外力使用环境下仍保持良好的性能。