Colorless poly(ether-imide)s deriving from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and aromatic bis(ether amine)s bearing pendent trifluoromethyl groups

A series of poly(ether-imide)s (III) characterized by colorless, highly solubility was synthesized from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and various fluorinated aromatic diamines (Ia-h) in DMAc via polycondensation to form poly(amic acid) (II), followed by chemical (C) and thermal (H) imidization. These polymers had inherent viscosities ranging from 0.60 to 1.3 dL/g. These polyimides were highly soluble in a variety of organic solvent such as amide-type, ether-type and chlorinated solvents. Moreover, these poly(ether-imide) films were almost colorless, with an ultraviolet–visible absorption cutoff wavelength below 390 nm and low b* value (a yellowness index) of 4.6–18.0. The III series showed strength tensile of 72–101 MPa, elongation at break of 11–25%, initial modulus of 1.5–2.0 GPa. The glass transition temperature (Tg) of IIIa-h were in the range of 202–267 °C, and the decomposition temperature above 493 °C and left 40–65% char yield at 800 °C in nitrogen. They had the lower dielectric constants of 3.39–3.72 (1 MHz) and moisture absorptions in the range of 0.11–0.40%.