Polyimides 6: Synthesis, characterization, and comparison of properties of novel fluorinated poly(ether imides)

Five new poly(ether imides) have been prepared on reaction with oxydiphthalic anhydride (ODA) with five different diamines: 1,4‐bis( p ‐aminophenoxy‐2′‐trifluoromethyl benzyl) benzene, 4,4′‐bis( p ‐aminophenoxy‐2′‐trifluoromethyl benzyl) benzene, 1,3‐bis( p ‐aminophenoxy‐2′‐trifluoromethyl benzyl) benzene, 2,6‐bis( p ‐aminophenoxy‐2′‐trifluoromethyl benzyl) pyridine, and 2,5‐bis( p ‐aminophenoxy‐2′‐trifluoromethyl benzyl) thiophene. Synthesized polymers showed good solubility in different organic solvents. The polyimide films have low water absorption of 0.3–0.7%, low dielectric constants of 2.82–3.19 at 1 MHz, and high optical transparency at 500 nm (>73%). These polyimides showed very high thermal stability with decomposition temperatures (5% weight loss) up to 531°C in air and good isothermal stability; only 0.4% weight loss occurred at 315°C after 5 h. Transparent thin films of these polyimides exhibited tensile strength up to 147 MPa, a modulus of elasticity up to 2.51 GPa and elongation at break up to 30% depending upon the repeating unit structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 821–832, 2004