Transparent and Soluble Polyimide Films Containing 4,4 '-Isopropylidenedicyclohexanol (Cis-HBPA) Units: Preparation, Characterization, Thermal, Mechanical, and Dielectric Properties

摘要

To develop colorless and soluble polyimide films, cis-hydrogenated bisphenol A (cis-HBPA) was successfully separated from HBPA isomers, and two novel monomers containing cis-HBPA unit, 4,4'-(4,4'-isopropenylbicyclohexyloxy) diphthalic anhydride (HBPADA) and 4,4'-(4,4'-isopropenylbicyclohexyloxy) dianiline (f) were designed and synthesized. PI-(1 - 5) were achieved from HBPADA and five kinds of aromatic diamines and PI - 6 from HBPADA and semiaromatic diamine f via a two-step thermal imidization. All the polyimides could afford flexible, tough, and transparent films with transparency as high as 86% at 450 nm. Surprisingly, the polyimides containing cis-HBPA unit exhibited excellent solubility not only in polar solvents such as N, N-dimethylacetamide, but also in low boiling solvents such as chloroform and dichloromethane. Additionally, analogues aromatic PI - 7 derived from 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) and 2,2-bis(4-aminophenyl)hexafluoropropane (e) was obtained for comparison with PI-(1 - 6) on aspects of thermal, mechanical, soluble, optical, electrical, and morphological properties. The structure-property relationships of PI-(1 - 7) were investigated in detail. (c) 2018 Wiley Periodicals, Inc.