Optically transparent and colorless poly(ether-imide)s derived from a phenylhydroquinone bis(ether anhydride) and various trifluoromethyl-substituted bis(ether amine)s

A series of colorless and organosoluble poly(ether-imide)s (PEIs) were prepared from a phenylhydroquinone bis(ether anhydride), i.e., 2,5-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, and seven trifluoromethyl-containing bis(ether amine)s by the conventional two-stage process via the thermal or chemical imidization of the precursor poly(amic acid)s. The fluorinated PEIs prepared via the chemical imidization procedure had inherent viscosities of 0.46-1.27 dL/g and weight-average molecular weights of 68,000-87,500. The PEIs exhibited good solubility in a variety of organic solvents; they were readily soluble in amide-type polar solvents and chlorinated hydrocarbons on a concentration higher than 10%. The solution-cast films showed a high optical transparency and low color intensity, with an ultraviolet-visible absorption edge of 368-375 nm and a yellowness index of 5.9-9.9. These films were flexible and tough with tensile strengths of 89-114 MPa. They exhibited glass-tranisition temperatures of 198-250A degrees C and 10% weight loss temperatures higher than 488A degrees C in air or nitrogen. In addition, these PEI films also displayed low dielectric constants (3.22-3.52 at 1 MHz) and low moisture absorptions (0.22-0.73 wt%).