【摘要】 采用乙酸酐/吡啶催化体系，通过改变体系添加量，制备了不同化学亚胺化程度的聚酰胺酸-酰亚胺(PA-I)薄膜，然后在不同温度下进行单轴拉伸，再经热亚胺化制得聚酰亚胺(PI)薄膜。系统探究了亚胺化程度与拉伸温度协同作用对PI薄膜聚集态结构和力学性能、热性能及光学性能的影响。结果表明，亚胺化程度主导分子链刚柔性，而拉伸温度是决定分子取向的关键参数，二者存在显著协同效应。在中等亚胺化程度(约60%)下，分子链刚柔平衡，结合最佳拉伸温度(260℃)能实现PI薄膜最高的分子有序程度和最优的力学性能。薄膜的热稳定性受亚胺化程度影响较小，完全亚胺化形成的致密网络有效抵消了拉伸潜在的热劣化效应。拉伸导致分子取向排列，增加了光散射，使薄膜的可见光透过率略有下降且黄色指数上升，但亚胺化程度约为60%的样品综合光学性能最佳。综上，约60%亚胺化程度结合260℃拉伸温度是实现PI薄膜高有序程度、优异力学性能与良好光学特性平衡的最优工艺组合，为高性能PI薄膜的精密制造提供了理论依据和工艺优化路径。更多还原

【Abstract】 Using acetic anhydride/pyridine catalytic system,polyamide acid imide(PA-I) films with different chemical imidization degrees were prepared by varying the additives of the system,then,the uniaxial stretching was carried out at different temperatures,and the polyimide(PI) films were prepared by thermal imidization. The influences of synergism between imidization degree and stretching temperature on the aggregation structure,mechanical properties,thermal properties,and optical properties of PI films were systematically investigated. The results demonstrate that imidization degree governs molecular chain rigidity-flexibility,while stretching temperature is a critical parameter that determines molecular orientation,revealing significant synergism between the two parameters. At a moderate imidization degree(about 60%),molecular chains achieve optimal rigidity-flexibility balance,combined with the optimal stretching temperature(260 ℃),the highest molecular order degree and best mechanical properties of PI films can be obtained. The thermal stability of PI films are minimally affected by imidization degree,the dense network formed by complete imination effectively counteracts the potential thermal deterioration effect of stretching. Stretching-induced molecular orientation increases light scattering,slightly reducing visible-light transmittance and increasing yellowness index. Nevertheless,the sample with about 60% imidization degree exhibits the best overall optical performances. In conclusion,the combination of about 60% imidization degree coupled with 260 ℃ stretching temperature represents the optimal process to achieve a balance of high molecular order degree,superior mechanical properties,and favorable optical characteristics of PI films. This provides theoretical foundation and process optimization route for precision manufacturing of high-performance PI films.更多还原