一类含甲基结构高透明聚酰亚胺的合成与性能研究

Synthesis and properties of a class of high transparent polyimides containing methyl structure

摘要:

以2,6-二氨基甲苯、3,3',4,4'-联苯四甲酸二酐、3,3',4,4'-二苯醚四甲酸二酐为原料，间甲酚作为溶剂，经一步法高温共缩聚，制备一系列可溶性共聚型聚酰亚胺(MPI)。利用红外光谱（FTIR）、核磁共振波谱（1H NMR）、差式扫描量热仪（DSC）、热重分析仪（TGA）和紫外-可见光分度计（UV）等测试仪器对MPI进行结构与性能表征。结果表明：红外与核磁的数据说明成功合成了含甲基结构的聚酰亚胺；该系列的含甲基聚酰亚胺在室温下可溶于N-甲基吡咯烷酮（NMP）、N,N-二甲基乙酰胺（DMAc）、二氯甲烷（CH2Cl2）三氯甲烷（CHCl3）、二甲基亚砜（DMSO）等有机溶剂，具有良好的溶解性和成膜性，并随着联苯酐的含量增加溶解性降低；同时该系列MPI制得的薄膜具有良好的光学透过性能，在紫外光波长450 nm时的透过率均在74%以上，截止波长在350 nm左右；该系列MPI的起始分解温度均大于457 ℃，800 ℃氮气氛围中的焦炭产率均大于63%，玻璃化转变温度在260 ℃~285 ℃之间，表现出优异的热学性能。此外，MPI-1~MPI-4薄膜还具有良好的机械性能，其弹性模量在1.7~2.1 GPa，拉伸强度在89.7~120.6 MPa，断裂伸长率在19.7%~28.4%。

Abstract:

A series of soluble methyl-containing polyimides (MPI) were prepared by a one-step high-temperature copolymerization using 2,6-diaminotoluene(TDA), 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride(ODPA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride(BPDA) as monomers and m-cresol as the solvent. Their structures and properties were tested by FTIR, 1HNMR, DSC, TGA, UV, etc. The series of methyl-containing polyimides had good solubility in NMP, DMAc, DMSO, DMF, CH2Cl2 and CHCl3 at room temperature, and their solubility decreased as increasing of the content of biphenyl anhydride. The obtained films showed good optical transmission properties, and the transmittance at the ultraviolet light wavelength of 450 nm was above 74%, and the cutoff wavelengths were around 350 nm. The series of polyimides also had good thermal properties. The initial decomposition temperatures of this series of MPI were more than 457 °C, and their glass transition temperatures were in the range of 260 °C~285 °C. The elastic modulus, tensile strength and elongation at break of the prepared films were in the range of 1.7~2.1 GPa, 89.7~120.6 MPa and 19.7%~28.4%, respectively.