Oxadiazole polymers
AssigneeImperial Chemical Industries PLC
InventorsAlexander Blackhall, Donald Lithgow Brydon, John David Seddon
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Abstract
The production of a brominated, polyarylene - 1, 3, 4- oxadiazole solution in oleum involves adding bromine to a precursor solution of the polymer, wherein the polymer is capable of further polymerization and the solution has a viscosity below a predetermined minimum value, and then further polymerizing the brominated polymer to an extent which effects an increase in the viscosity to at least the predetermined minimum value.
Claims6
A method for the production of a brominated, polyphenylene-1,3,4-oxadiazole solution having a viscosity above the minimum for subsequent effective extrusion, which comprises
- a. forming a precursor solution of a polyphenylene-1,3,4-oxadiazole polymer by reacting at least one acid, selected from the group consisting of isophthalic acid and terephthalic acid, in oleum having a strength in the range 5 to 60%, with a compound selected from the group consisting of hydrazine and hydrazine salts in amounts such that the polymer has --COOH end groups making it capable of further polymerization, and the solution has a viscosity below the minimum for subsequent effective extrusion,
- b. adding bromine to the precursor solution to brominate the polymer;
- and then
- c. adding a compound selected from the group consisting of hydrazine and hydrazine salts to further polymerize the brominated polymer to an extent which effects an increase in the viscosity of the solution to or above the minimum for subsequent effective extrusion.
Dependencies are inferred from the claim text.