基于刚性脂环四羧酸二酐的无色透明聚酰亚胺薄膜的制备与性能

Preparation and Properties of Colorless Transparent Polyimide Films Based on Rigid Alicyclic Tetracarboxylic Anhydride

随着柔性显示领域的不断发展,无色透明聚酰亚胺(CPI)薄膜的研究受到广泛关注.本研究以刚性脂环四羧酸二酐CpODA为主体,选用多种不同的商业化二胺单体制备出对应的聚酰胺酸(PAAs),通过梯度升温环化得到一系列半芳香聚酰亚胺薄膜(PIs),研究-CF_(3)侧基、酰胺键结构对于改善薄膜光学透明性和热稳定性能之间的相互关系.研究发现酰胺结构的引入对聚合物薄膜的玻璃化转变温度和热膨胀系数具有突出影响,使制备薄膜的玻璃化转变温度高达472℃,热膨胀系数(CTE,50~250℃)甚至小于10×10^(-6) K^(-1).三氟甲基的引入对薄膜透明性具有一定的提升作用,其光学透明性T450 nm最高达87%,截止波长λcutoff范围为289~384 nm.值得注意的是,基于CpODA刚性脂环结构的基础上,PI薄膜的最低热处理温度为350℃,依然具有良好的光学透过率和较低的CTE值,为CPI的发展提供基础.

With the development of flexible display,colorless polyimide(CPI)films have attracted extensive attention.In this study,rigid aliphatic tetracarboxylic acid(CpODA)was used as the main body,and a variety of commercial diamine monomers were selected to prepare corresponding poly(amic acid)s(PAAs).A series of colorless polyimide films(PIs)were obtained by gradient temperature cyclization.The relationship between―CF3 side group and amide bond structure to improve the optical transparency and thermal stability of the films was studied.It is found that the introduction of amide structure has a significant effect on the glass transition temperature and thermal expansion coefficient of polymer films,making the glass transition temperature of the film up to 472℃,thermal expansion coefficient(CTE,50‒250℃)even less than 10×10^(-6) K^(-1).The introduction of trifluoromethyl has a certain effect on the transparency of the film,the optical transparency of T450nm up to 87%,cut-off wavelength(λcutoff)range of 289‒384 nm.It is worth noting that based on the rigid lipid ring structure of CpODA,the minimum heat treatment temperature of PI film is 350℃,and it still has good optical transmittance and low CTE value,which provides the basis for the development of CPI.