United States of America As Represented by the Secretary of the Air Force

George J Moore

Robert C Evers

My Dotrong

Fusible, rod-like, graft polymers and copolymers having repeating units of the formula: ##STR1## wherein x ranges from 0 to about 0.97, y is 1-x, Y is a poly(etherketone) (PEK) or a poly(etheretherketone) (PEEK), and wherein Ba is a benzobisimidazole or benzobisthiazole moiety are provided. Also provided are methods for preparing the above polymers and copolymers, 2-(2,6-dimethylphenoxy)terephthalic acid and a method for preparing the latter.

Rigid-rod graft polymers and copolymers

Aromatic polyamide resins having repeating units, each containing at least one m-ethynyl amido subunit: ##STR1## These resins can be thermally treated to undergo intra-molecular cyclization, without evolution of volatiles, into polyimidines containing the following subunit. ##STR2##

Ethynyl-containing aromatic polyamide resin

Aromatic monomers, each containing at least one o-ethynyl carboxylic acid halide subunit: ##STR1## wherein X is Cl or Br. These monomers can be reacted with amines to form aromatic polyamide resins which can be thermally treated to undergo intromolecular cyclization, without evolution of volatiles, into polyimidines.

Ethynyl-containing phthaloyl halides

2-Amino-4-ethynylphenol, a novel compound, is prepared by a four-step synthetic sequence in which the key reaction is the treatment of 4-acetoxy-3-nitroacetophenone with a Vilsmeier reagent derived from N,N-dimethylformamide and phosphorus oxychloride. The compound is useful as an endcapping agent in the synthesis of fluorocarbon ether bibenzoxazole oligomers which, because of the presence of acetylenic terminal groups, can be cured by thermal means to provide broad-use temperature, fuel and fluid resistant vulcanizates.

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Dayton, OH, United States of America

George J Moore