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US 12,065,763 B2Granted
Method of making a phosphonated PBI fiber
AssigneePBI Performance Products, Inc.
InventorsBrian P. Shiels, Gregory S. Copeland, Feng Qin
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Abstract
A method of making a phosphonated polybenzimidazole fiber comprises the steps of: spinning an untreated PBI resin into a PBI fiber; treating the PBI fiber with phosphoric acid, and thereby obtaining a PBI fiber with 1-25 wt. % phosphoric acid APU. A fiber is made with a polybenzimidazole (PBI) polymer with a phosphoric acid pick-up (APU) in the range of 1-25% (PBI-p fiber). The PBI-p fiber may have a LOI≥50% and/or an initial thermal decomposition temperature in air of ≥555° C.
Claims5
A method of making a phosphonated polybenzimidazole (PBI) fiber comprising the steps of:
- spinning an untreated PBI resin into a PBI fiber;
- immersing the PBI fiber in a phosphoric acid bath, wherein the bath is maintained at 35° C.;
- squeezing the phosphoric acid-treated PBI fiber to dry the fiber;
- washing the squeezed-dry PBI fiber with water at room temperature;
- drying the washed PBI fiber in an air non-contact oven at 350° C.;
- and
- heat-treating the air-dried PBI fiber in a nitrogen-blanketed oven at 565° C. to fix the acid within the polymer structure;
- thereby obtaining a phosphonated PBI fiber with a phosphoric acid pick-up (APU) in the range of 1-25 wt % and having a Limiting Oxygen Index (LOI) per ASTM 2863 of about ≥47%.
5 more elements
Dependencies are inferred from the claim text.