MANUFACTURE OF CARBON FILAMENTS OF HIGH STRENGTH AND MODULUS

• US 3,607,063 A
• Filed: 10/09/1969
• Issued: 09/21/1971
• Est. Priority Date: 10/09/1969
• Status: Expired due to Term

• Current Assignee: Frank C. Douglas, Robert W. Stielau, Thomas K. Gregory
• Original Assignee: Frank C. Douglas, Robert W. Stielau, Thomas K. Gregory
• Inventors: Douglas, Frank C., Gregory, Thomas K., Stielau, Robert W.
• Primary Examiner(s): Meros, Edward J.
• Application Number:
  US04/865,119
• Time in Patent Office: 712 Days
• Field of Search: 23/209.3,209.1 219/10.61,10.55 13/7 204/173 264/25,26,29
• US Class Current: 423/447.1
• CPC Class Codes: D01F 9/14 by decomposition of organic filaments
• CPC Class Codes: D01F 9/16 from products of vegetable origin or derivatives thereof, e.g. from cellulose acetate D01F9/18 takes precedence

Abstract

A method for continuously producing carbon strand of high tensile strength and modulus comprising passing carbonized filament through an electrically conductive enclosure, generating a current of radiofrequency in an oscillatory circuit connected to the enclosure and establishing an electric field axially oscillating at the radiofrequency within the enclosure of sufficient density to heat the carbon filament to graphitization temperature.

Claims

2. In those processes for continuously manufacturing high-strength, high-modulus carbon filaments by heating pyrolyzed polymeric filaments to 2,000*-3,500* C. the improvement which comprises electromagnetically coupling the filaments to radiofrequency source means by passing said filaments axially through a cavity coupler to expose said filaments to an axial oscillating electric field having a density sufficiently high to cause current flow in the filaments to effect said heating.

3. The invention of claim 2 wherein said cavity coupler is a quarter-wave cavity coupler.

4. A method for the continuous manufacture of high-strength, high-modulus carbon filaments comprising moving preformed pyrolyzed polymeric filaments axially through a quarter-wave cavity and a capacitor located within the cavity and establishing a radiofrequency electric field within said cavity with a peak density between the plates of the capacitor of sufficient intensity whereby current is caused to flow in said filaments to heat the same to graphitization temperature.