# US 5,344,896 A · Water soluble rigid-rod polymers

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- Number: US 5,344,896 A
- Document ID: US5344896A
- Status: Granted
- Kind: A
- Application number: 08/192,901
- Filed: 1994-02-07
- Granted: 1994-09-06
- Earliest claimed: 1993-03-12
- Assignees: The United States of America as represented by the Secretary of the Air Force
- Inventors: Thuy D. Dang; Fred E. Arnold
- Web page: https://patentgrep.com/patent/US5344896A

## CPC

- C08G 75/32: Polythiazoles; Polythiadiazoles
- C08G 73/18: Polybenzimidazoles
- C08G 73/22: Polybenzoxazoles
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

Water-soluble rigid-rod aromatic heterocyclic polymers having repeating units of the formula: ##STR1## wherein n has a value of 0.05 to 1.00, M is an alkali metal, Q is a benzobisazole of the formula ##STR2## wherein X is --S-- or --O--, and R is selected from the group consisting of: ##STR3##

## Claims

### Claim 1

A water-soluble rigid-rod aromatic heterocyclic polymer having repeating units of the formula: ##STR7## wherein n has a value of 0.05 to 1.00, M is an alkali metal, Q is a benzobisazole of the formula ##STR8## wherein X is --S-- or --O--, and R is: ##STR9##

### Claim 2 (depends on 1)

The polymer of claim 1 wherein R is ##STR10##

### Claim 3 (depends on 1)

The polymer of claim 1 wherein R is ##STR11##

### Claim 4 (depends on 1)

A method for preparing the water-soluble para-oriented aromatic heterocyclic polymer of claim 1, which comprises treating a para-oriented aromatic heterocyclic polymer which is at least partially soluble in an aprotic solvent and has repeating units of the formula: ##STR12## wherein n has a value of 0.05 to 1.00, Q is a benzobisazole of the formula ##STR13## wherein X is --S-- or --O--, and R is: ##STR14## with a hydride to form the corresponding polyanion, treating the polyanion with 2-propanesultone and recovering the resulting water-soluble propane sulfonate polymer.