Thermo-oxidatively stabilized polybenzimidazole-containing articles
US5277981A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1992 |
| Grant date | Jan 11, 1994 |
| Priority date | — |
| Expiry date | May 28, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/30
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A process for enhancing the thermo-oxidation stability of a polybenzimidazole-containing article wherein the article contains from about 5 to about 100 weight percent of polybenzimidazole and from about 0 to about 95 weight percent of a thermoplastic polymer, by the steps of providing a phosphoric acid solution of about 2.0 to about 10.0 weight percent of acid; contacting the polybenzimidazole-containing article with the acid solution for sufficient time to produce an acid-treated article; drying the acid-treated article at a low temperature to remove excess acid; and heat treating the dried article at a temperature ranging from about 400.degree. to about 500.degree. C. in an inert atmosphere to form a phosphate barrier layer on the surface of the article, wherein the article retains at least about 50 percent of its weight after isothermal aging at about 600.degree. F. for a period of at least about 300 hours.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.