Method for making heterocyclic block copolymer
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorsTsu-Tzu Tsai, Fred E. Arnold
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Abstract
Thermally stable aromatic heterocyclic block copolymers are prepared by reacting a diamino monomer and terephthalic acid to form a carboxy-terminated rigid rod segment and then polymerizing a carboxy-monoamine monomer therewith to form flexible segments grafted onto the rigid rod segments.
Claims12
A method for preparing a thermally stable aromatic heterocyclic block copolymer of the general formula ##STR4## wherein m is an integer equal to the number of repeating units of the rigid rod segment and n is an integer equal to the number of repeating units of the flexible end segments, which comprises the steps of
- (a) reacting 2,5-amino-1,4-dithiobenzene with terephthalic acid in polyphosphoric acid (PPA) under reaction conditions to form carboxy-terminated rigid rod segments;
- (b) adding an amino monomer of the general formula ##STR5## to the reaction mixture of PPA and rigid rod segments, and polymerizing said amino monomer to form flexible segments grafted onto said rigid rod segments;
- and
- (c) recovering the resulting block copolymer.
A method for preparing a thermally stable aromatic heterocyclic block copolymer of the general formula ##STR6## wherein m is an interger equal to the number of repeating units of the rigid rod segment and n is an integer equal to the number of repeating units of the flexible end segments, which comprises the steps of
- (a) reacting 1.5-diamino-2.4-dithiabenzene with terephthalic acid in polyphosphoric acid (PPA) under reaction conditions to form carboxy-terminated rigid rod segments:
- (b) adding an amino monomer of the general formula ##STR7## to the reaction mixture of PPA and rigid rod segments, and polymerizing said amino monomer to form flexible segments grafted onto said rigid rod segments:
- and
- (c) recovering the resulting block copolymer.
Dependencies are inferred from the claim text.