Process for gas phase surface treatment
AssigneeCytec Industries Inc.
InventorShao C. Chiu
Life of this patent
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Abstract
A gas phase surface treatment for treating carbon fiber including (a) exposing a carbon fiber to a gaseous oxidizing atmosphere to form a modified carbon fiber with an oxidized fiber surface; followed by (b) exposing the oxidized fiber surface to a gaseous nitrogen-containing atmosphere to form a modified carbon fiber with a nitrogen-enriched surface, wherein the nitrogen-enriched surface exhibits an increase in surface nitrogen to surface carbon (N/C) ratio as compared to the surface of the carbon fiber prior to exposure at (a). Steps (a) and (b) are carried out continuously without any additional intervening surface treatment.
Claims18
A gas phase surface treatment for treating a continuous carbon fiber, comprising:
- a) exposing a moving continuous carbon fiber to a gaseous oxidizing atmosphere to form a modified carbon fiber with an oxidized fiber surface;
- followed by
- b) exposing the moving continuous carbon fiber with the oxidized fiber surface to a gaseous nitrogen-containing atmosphere comprising at least 50% by volume of ammonia gas to form a modified carbon fiber with a nitrogen-enriched surface, wherein the nitrogen-enriched surface exhibits an increase in surface nitrogen to surface carbon (N/C) ratio as compared to the surface of the carbon fiber prior to exposure at (a),
- wherein steps (a) and (b) are carried out continuously without any additional intervening surface treatment,
- wherein step (a) is carried out for a period of 0.5-2 minutes, and step (b) is carried out for a period of 0.5-2 minutes.
A continuous process for manufacturing carbon fiber comprising:
- i. passing a continuous polyacrylonitrile (PAN) fiber through an oxidation zone to form a stabilized PAN fiber;
- ii. passing the stabilized PAN fiber through a carbonization zone to form a continuous carbon fiber;
- iii. exposing the continuous carbon fiber to a gaseous oxidizing atmosphere to form a modified carbon fiber with an oxidized fiber surface;
- and
- iv. exposing the oxidized fiber surface to a gaseous nitrogen-containing atmosphere comprising at least 50% by volume of ammonia gas to form a modified carbon fiber with a nitrogen-enriched surface, wherein the nitrogen-enriched surface exhibits an increase in surface nitrogen to surface carbon (N/C) ratio as compared to the surface of the carbon fiber prior to exposure at (iii),
- wherein steps (i) to (iv) or steps (ii) to (iv) are carried out continuously,
- wherein step (iii) is carried out for a period of 0.5-2 minutes, and step (iv) is carried out for a period of 0.5-2 minutes.
Dependencies are inferred from the claim text.