Highly organosoluble and flexible polyimides with color lightness and transparency based on 2,2‐bis[4‐(2‐trifluoromethyl‐4‐aminophenoxy)‐3,5‐dimethylphenyl]propane

A new diamine containing isopropylidene, methyl substituted arylene ether, and trifluoromethyl groups, 2,2‐bis[4‐(2‐trifluoromethyl‐4‐aminophenoxy)‐3,5‐dimethylphenyl]propane (BTADP), was synthesized and used in preparation of a series of polyimides by direct polycondensation with various aromatic tetracarboxylic dianhydrides in N, N‐dimethylacetamide (DMAc). All polymers derived from diamine (BTADP) with trifluoromethyl substituents were highly organosoluble in the solvents, like N‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylacetamide, N,N‐dimethylformamide (DMF), pyridine, chloroform, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), dichloromethane, cyclohexanone, and γ‐butyrolactone at room temperature or upon heating at 70 °C. Inherent viscosities of the polyimides were found to range between 0.58 and 0.97 dL·g^?1. These polyimides had glass transition temperatures between 256 and 307 °C, and their 10% mass loss temperatures ranged from 440 to 462 °C and 421 to 443 °C under nitrogen and air, respectively. These polyimides had low dielectric constants in the range of 2.84–3.09. All the polyimides could be cast into films from DMAc solutions and were thermally converted into color lightness, optically transparent, flexible, and tough polyimides. The polyimide films had a tensile strength in the range of 83–97 MPa and a tensile modulus in the range of 2.0–2.2 GPa. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5766–5774, 2004