Preparation and Properties of Organosoluble,Colorless,and High-Pretilt-Angle Polyimides Based on an Alicyclic Dianhydride and Long-Main-Chain Alkyl-Group-Containing Diamines

摘要

Alicyclic polyimides (PIs) were prepared from 3-carboxylmethyl-cyclopentane-1,2,4-tricarboxylic acid dianhydride and #alpha#,#omega#di(4-aminophenoxyl)alkanes.These PIs possessed good solubility in aprotic,strongly polar solvents such as N-methyl-2-pyrrolidone,N,N-dimethylacetamide,N,N-dimethyl formamide,and m-cresol.They possessed high transparency in visible wavelengths and were almost colorless.The pretilt angle of a liquid-crystal display with these PIs as the alignment layer increased linearly as the length of the alkyloxy groups increased;it was close to 5deg for the PI samples PI-10 and PI-12.