Celanese Gmbh

Michael J Ram

Lowell G Saferstein

Arnold J Rosenthal

Andrew J Manning

Charles M Clarke

An improved process is provided for the formation of metal ion containing carbon fibers which particularly are suited for utilization in electron shielding applications. An acrylic fibrous material is formed having substantially uniformly dispersed therein a halide of a transition metal. The metal halide (e.g. a chloride) present within the fibrous material is (1) converted to an oxide, (2) the fibrous material containing the metal oxide is heated in an oxygen-containing atmosphere until thermally stabilized, and (3) the thermally stabilized fibrous material is carbonized or carbonized and graphitized at a more highly elevated temperature in an appropriate atmosphere. The resulting product comprises ions of a transition metal substantially uniformly dispersed in an amorphous carbon or graphitic carbon matrix. The halide of a transition metal may be incorporated into the acrylic precursor by co-spinning and/or padding prior to thermal stabilization. The conversion of the halide of a transition metal to an oxide prior to thermal stabilization may be conducted by contact with a base or with an oxidizing agent as described.

Production of metal ion containing carbon fibers useful in electron

A process is provided for the efficient conversion of acrylonitrile homopolymer fibrous materials and closely related acrylonitrile copolymer fibrous materials to graphitic fibrous materials of high tenacity. The process incorporates an initial brief fiber healing step which is conducted at a temperature of about 170.degree. to 220.degree.C., a preoxidation step, and a tandem carbonization/graphitization step as described. The relationship of the various variables required to produce the high tenacity graphitic fibrous product is set forth in the equation provided. In a preferred embodiment of the invention the carbonization/graphitization step of the process is conducted on a reliable and stable basis wherein the desired tenacity is achieved without the necessity of resorting to the exertion of high longitudinal tensions upon the preoxidized acrylic fibrous material.

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West Orange, NJ, United States of America

Michael J Ram