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-dimethylform-amide (DMF), pyridine, chloroform, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), dichloromethane, cyclohexanone, and gamma-butyrolactone at room temperature or upon heating at 70 degreesC. 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 degreesC, and their 10% mass loss temperatures ranged from 440 to 462 degreesC and 421 to 443 degreesC 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. (C) 2004 Wiley Periodicals, Inc.