Ethynyl terminated ester oligomers and polymers therefrom
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsPaul M. Hergenrother, Stephen J. Havens
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Abstract
A new class of ethynyl-terminated oligomers and the process for preparing same are disclosed. Upon the application of heat, with or without a catalyst, the ethynyl groups react to provide crosslinking and chain extension to increase the polymer use temperature and improve the polymer solvent resistance. These improved polyesters are potentially useful in packaging, magnetic tapes, capacitors, industrial belting, protective coatings, structural adhesives and composite matrices.
Claims14
An ethynyl terminated ester oligomer for producing a cured polymer having improved solvent resistance, higher use temperature and synthesized according to the general reaction ##STR6## where PE refers to the polyester radical portion,
- n is an integer and represents 4 to 100 repeat units, base refers to an organic base selected from the group consisting of triethylamine, pyridine, quinoline, diethylamine and piperidine,
- R is selected from the group of radicals consisting of ##STR7## and mixtures thereof, and R' is selected from the group of radicals consisting of ##STR8## and mixtures thereof.
A method for preparing an ethynyl-terminated polyarylate comprising:
- (a) dissolving a quantity of an hydroxy-terminated polyarylate in a solvent selected from the group consisting of ethonol-free chloroform, methylene chloride and N,N-dimethylacetamide and containing at least an equimolar quantity of an organic base selected from the group consisting of triethylamine, pyridine, quinoline, diethylamine, and piperidine,
- (b) dissolving at least an equimolar quantity of an ethynylbenzoyl chloride in a solvent also selected from the group of solvents listed above and adding the resultant to the stirred solution of hydroxy-terminated polyarylate obtained in step (a) over a period of five minutes and continuing stirring for approximately three hours,
- (c) precipitating a polymer from the stirred solution,
- (d) washing the precipitate, and
- (e) drying the washed precipitate to recover a yield of ethynylbenzoyloxy-terminated polyarylate.
An ethynyl-terminated ester oligomer formed as the reaction product of an hydroxy-terminated ester oligomer and 4-ethynylbenzoyl chloride.
A method of increasing the solvent resistance and T.sub.g of 4-ethynylbenzoyloxy-terminated polyarylate (ETPA) by thermally reacting 70-90% by weight thereof with 10-30% by weight of 2,2-bis(4,ethynylbenzoyloxy-4-phenyl) propane to yield a material having improved solvent resistance and a higher T.sub.g than that of the ETPA alone.
Dependencies are inferred from the claim text.