Abstract: A gut is provided for a sports racket such as a tennis racket. The gut is made with carbon fibers. The gut may be made solely of carbon fibers or there may be a combination of carbon fibers and organic and/or inorganic fibers. A coating may be provided for the resultant product which may be a synthetic resin or metallic. The carbon fiber is above 150 kg/mm.sup.2 in tensile strength.

Abstract: A process for the preparation of carbon fibers from polyacrylonitrile type fibers, comprising oxidizing the polyacrylonitrile type fibers to form oxidized fibers therefrom and carbonizing said oxidized fibers in an acidic atmosphere containing a small amount of hydrogen chloride and, if desired, a small amount of moisture with the remainder being an inert gas, thereby obtaining the carbon fibers.This invention relates to a process for the production of high-strength carbon fibers which are excellent as reinforcing material for use in a composite material or article.Carbon fibers prepared by heating polyacrylonitrile type or other type fibers to carbonize or further graphitize the fibers have heretofore been used as reinforcing material for composing a composite material or article together with a plastic, metallic, ceramic or other material since such carbon fibers have high strength and elastic modulus as their features.