Highly Soluble and Transparent of Novel Polyimides Containing Trifluoromethyl and Cyclohexane Units

Abstract

Two novel polyimides(PIs) were polymerized from 1,4-bis((4-amino-2-(trifluoromethyl)phenoxy)methyl)cyclohexane, with aromatic tetracarboxylic dianhydrides using the typical one-step method. The inherent viscosity of the PIs were around 0.90dL/g, and they exhibited an excellent solubility and optical property. They were readily soluble not only in some strong polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), but also in some low-boiling-point solvents such as chloroform (CDCl3), and tetrahydrofuran (THF). The PIs film showed high optical transparency and colorless with cut-off wavelength in 332nm and 338nm. Meanwhile, the temperature of 10% weight loss in air and nitrogen were higher than 441°C and 449°C respectively, and their glass-transition temperature (Tg) were higher than 348 °C. Furthermore, they possessed good mechanical properties with tensile strengths of 69–71MPa, elongations at break of 11.6–15.4% and low moisture absorption (<2%).Due to their properties, the polyimides could be considered as photoelectric and micro-electronic materials.