| 摘要 |
PURPOSE:To manufacture a carbon fiber having high strength and modulus and excellent heat-stability, and free from yarn defect, by baking a fiber composed of a copolymer of acrylonitrile and a small amount of a carboxyl-containing monomer, etc. and free of alkali metal. CONSTITUTION:An acrylonitrile copolymer essentially free from alkali metal is prepared by copolymerizing (A) >=95(wt)% acrylonitrile, (B) 0.05-3.0% carboxyl- containing monomer (e.g. acrylic acid) and (C) 0.1-1.2% monomer containing sulfonic acid group (e.g. 2-acrylamido-2-methylpropanesulfonic acid and its amine salt). The fiber of the copolymer is baked to obtain the objective fiber. To eliminate the alkali metal, the polymerization is carried out in the presence of an alkali metal-free polymerization catalyst, and >=20% of the total molar number of the carboxylic acid group and the sulfonic acid group is used in the form of ammonium salt or amine salt.
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