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US 4,729,820 AGranted
Multielectrolyte shear treatment of carbon fibers
AssigneeAmoco Corporation
InventorStuart Mitchell
Life of this patent
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Abstract
Carbon fibers subjected to an electrolytic treatment in an oxidizer bath followed by electrolytic treatment in an ammonium bath have surface elemental content of oxygen greater than 7% and nitrogen greater than 4%. Composites based on the carbon fiber in combination with bis-maleimide type matrix resins have improved toughness and interfacial bonding.
Claims9
A method of surface-treating carbon fibers comprising the steps of:
- (a) moving the carbon fiber, as anode, through a first electrolytic bath comprising an aqueous solution of an oxidizer;
- then
- (b) moving said carbon fiber, as anode, through a second electrolytic bath comprising an aqueous solution of an ammonium compound, said bath having a pH of at least about, 8.
A method of surface-treating carbon fibers comprising the steps of:
- (a) moving said fiber, as anode, through a first electrolytic bath comprising an aqueous solution of from about 0.5 to about 20 wt % nitric acid, followed by
- (b) moving said fiber, as anode, through a second electrolytic bath comprising from about 0.2 to about 5 M aqueous ammonium hydroxide.
Dependencies are inferred from the claim text.