Synthesis and characterization of novel fluorinated poly(ether imide)s containing pyridine and/or phenylphosphine oxide moieties

Abstract

4-(4-Trifluoromethylphenyl)-2,6-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]pyridine (9FPBAPP), as a new aromatic diamine, was prepared by a modified Chichibabin reaction of 4-(4-nitro-2-trifluoromethylphenoxy)acetophenone with 4-triflouromethylbenzaldehyde, followed by a catalytic reduction. A series of fluorinated poly(ether imide)s containing pyridine and/or phenylphosphine oxide moieties were prepared from bis(3-aminophenyl)phenylphosphine oxide (BAPPO), 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), and 9FPBAPP via a conventional two-step thermal imidization procedure with various mole ratios of BAPPO and 9FPBAPP. All the polymers were amorphous and soluble in common organic solvents such as N, N-dimethylacetamide and N-methyl-2-pyrrolidone and had Tg’s of 277–285°C, 5% weight loss temperature of 521–550°C in nitrogen. Furthermore, high char yields and good limited oxygen index values indicated that these polymers exhibited good thermal stability and flame-retardant property. Tough and flexible polymer films also had good mechanical properties with tensile strengths of 75–99 MPa, tensile moduli of 1.1–1.6 GPa, and elongations at break of 12%–24% and low dielectric constants of 2.81–3.53 (1 MHz), as well as high optical transparency with the ultraviolet cutoff wavelength in the range of 350–384 nm.