Synthesis of High Molecular Weight Fluorinated Poly(phthalazinone ether)s by Self‐Condensation of an AB‐Type Monomer and by Condensation of AA Monomers with Decafluorobiphenyl

Abstract

Two kinds of fluorinated phthalazinone monomers have been successfully synthesized. The fluorinated AB‐type phthalazinone monomer 4‐(4‐hydroxyphenyl)‐2‐(pentafluorophenyl)phthalazin‐1(2H)‐one was prepared by reaction of 2‐(hydroxybenzoyl)benzoic acid with 1‐(pentafluorophenyl)hydrazine. The fluorinated biphenol phthalazinone monomer 2,2′‐(perfluorobiphenyl‐4,4′‐diyl) ‐bis(4‐(4‐hydroxyphenyl)‐phthalazin‐1(2H)‐one) was synthesized by reaction of 2‐(hydroxybenzoyl)benzoic acid with (perfluorobiphenyl‐4,4′‐diyl)bis(hydrazine). High molecular weight fluorinated poly(phthalazinone ether)s were obtained by self‐condensation polymerization of the AB‐type phthalazinone monomer under mild reaction conditions or by condensation of the fluorinated bisphthalazinone monomer with decafluorobiphenyl. Detailed structural characterization of these monomers and polymers was carried out by a combination of 1H‐NMR, 19F‐NMR, and FTIR. The self‐condensation poly(phthalazinone ether) has a T g of 316°C, and a T d,−5% of 491°C. The poly(phthalazinone ether)s derived from AA phthalazinone monomers and decafluorobiphenyl have a similar T g , 220°C, and T d,−5%s higher than 467°C. These fluorinated poly(phthalazinone ether)s are soluble in many common solvents, and can be cast from chloroform solutions into tough, flexible films. These polymers cross‐link to give insoluble polymers when heated for a short time at 300°C.