Processes for hydrolyzing polyphosphoric acid in shaped articles

1. A process for hydrolyzing polyphosphoric acid in a shaped article comprising polyareneazole polymer and polyphosphoric acid, the process comprising:

a) removing surface liquid from the shaped article; and

b) contacting the shaped article with a hot surface having a temperature of at least about 150° degrees C. to hydrolyze polyphosphoric acid; and

c) subsequently removing hydrolyzed polyphosphoric acid from the hot-surface-contacted shaped article.

2. The process of claim 1 , wherein the hot surface comprises heated rolls.

3. The process of claim 1 , further comprising the step of:

d) drying the shaped article provided in step c).

4. The process of claim 1 , wherein the polyareneazole polymer is a polypyridazole.

5. The process of claim 4 , wherein the polypyridazole is a polypyridobisimidazole.

6. The process of claim 5 , wherein the polypyridobisimidazole is poly(1,4-(2,5-dihydroxy)phenylene-2,6-pyrido[2,3-d:5,6-d′]bisimidazole.

7. The process of claim 1 , wherein the polyareneazole polymer is a polybenzazole.

8. The process of claim 7 , wherein the polybenzazole is a polybenzobisoxazole.

9. The process of claim 1 , wherein a portion of the polyphosphoric acid is hydrolyzed during the contacting of the shaped article with a hot surface.

10. The process of claim 1 , wherein substantially all of the polyphosphoric acid is hydrolyzed during the contacting of the shaped article with a hot surface.

11. The process of claim 1 , wherein the shaped article comprises less than 2 percent phosphorus based on shaped article weight after removing hydrolyzed polyphosphoric acid from the shaped article.

12. The process of claim 1 , wherein the surface liquid is removed by evaporation, drying, blowing, absorption, scraping, wicking, stripping, dripping, or any combination thereof.