Optically transparent and organosoluble poly(ether imide)s based on a bis(ether anhydride) with bulky 3,3′,5,5′-tetramethylbiphenyl moiety and various fluorinated bis(ether amine)s

Novel optically transparent and organosoluble poly(ether imide)s (PEIs) were prepared from 4,4′-bis(3,4-dicarboxyphenoxy)-3,3′,5,5′-tetramethylbiphenyl dianhydride and various fluorinated bis(ether amine)s via chemical or thermal imidization. The effects of fluorinated groups and the imidization method on the properties of PEIs were investigated. Fluorinated PEIs prepared by the chemical imidization method exhibited essentially colorless characteristic with cutoff wavelengths lower than 380 nm, and yellowness index (b* values) ranging from 5.2 to 7.3, which are close to that of transparent polyarylate polymer (b* = 3.3). In addition, all fluorinated PEIs showed excellent solubility in common organic solvents. The thermal decomposition temperature at 10% weight loss is higher than 490°C, and the glass transition temperatures are in the range of 245–315°C. The fluorinated PEI series also exhibited low dielectric constants of 2.95–3.29 (1 MHz) and low moisture absorption in the range of 0.17–0.86 wt%, which are lower than the analogous nonfluorinated series.