Novel Soluble Fluorinated Poly(ether imide)s with Different Pendant Groups: Synthesis, Thermal, Dielectric, and Optical Properties

Three types of new bis(ether dianhydride) monomers, [4,4'-(2-(3'-methylphenyl)-1,4-phenylenedioxy)-diphthalic anhydride (4a)], (4,4'-(2-(3'-trifluoromethylphenyl)-1,4-phenylene-dioxy)-diphthalic anhydride (4b)], and [4,4'-(2-(3',5'-ditrifluoro-methylphenyl)-1,4-phenylenedioxy)-diphthalic anhydride (4c)] were prepared via a multistep reaction sequence. Three series of soluble poly(ether imide)s (PEIs) were prepared from the obtained dianhydrides by a two-step chemical imidization method. Experimental results indicated that all the PEIs had glass transition temperature in the range of 200-230 degrees C and the temperature of 5% weight loss in the range of 520-590 degrees C under nitrogen. The PEIs showed excellent solubility in a variety of organic solvents due to introduction of the bulky pendant groups and were capable of forming tough films. The casting films of PEIs (80-91 mu m in thickness) had tensile strengths in the range from 88 to 117 MPa, tensile modulus from 2.14 to 2.47 GPa, and elongation at break from 15 to 27%. The casting films showed UV-Vis absorption edges at 357-377 nm, low dielectric constants of 2.73-2.82, and water uptakes lower than 0.66 wt %. The spin-coated films of PEIs presented a minimum birefringence value as low as 0.0122 at 650 nm and low optical absorption at the optical communication wavelengths of 1310 and 1550 nm. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3281-3289, 2010