Low-ash polyacrylonitrile-based fiber, polyacrylonitrile-based carbon fiber and preparation method thereof

Abstract

The invention relates to a low-ash polyacrylonitrile-based fiber, a polyacrylonitrile-based carbon fiber and a preparation method thereof. The invention adopts the technical scheme that the preparation method of the low-ash polyacrylonitrile-based fiber comprises the following steps of oiling a fiber to be oiled to obtain an oiled fiber, wherein the swelling capacity of the fiber to be oiled is less than or equal to 80 percent, an oil agent used for oiling is prepared from crude oil and water, the concentration of the oil agent is smaller than or equal to 5 percent, a pH value of the crude oil is alkaline, the surface tension is smaller than or equal to 35 mN / m, the particle size is 200 to 400 nm, the antioxidant residue mass fraction in the air atmosphere is smaller than or equal to 10 percent, and the heat-resistant residue mass fraction in the nitrogen atmosphere is smaller than or equal to 10 percent; and carrying out drying densification treatment, steam drafting treatment and relaxation heat setting treatment on the oiled fiber to obtain the polyacrylonitrile-based fiber. According to the low-ash polyacrylonitrile-based carbon fiber, the ash content is less than or equal to 0.2 percent. According to the low-ash polyacrylonitrile-based fiber, the polyacrylonitrile-based carbon fiber and the preparation method thereof provided by the invention, the ash content of the polyacrylonitrile-based fiber and the polyacrylonitrile-based carbon fiber is mainly reduced, and broken filaments, fractured filaments, sticky filaments and doubled filaments are avoided.

Description

technical field [0001] The invention relates to the technical field of carbon fibers, in particular to a low-ash polyacrylonitrile-based fiber, polyacrylonitrile-based carbon fiber and a preparation method thereof. Background technique [0002] Carbon fiber material has both high performance and low density. It is a typical key material for military and civilian purposes and a typical representative of leading the material revolution. Polyacrylonitrile-based fibers are the most promising precursors for the production of high-performance carbon fibers. Carbon fibers prepared from polyacrylonitrile-based fibers have the best comprehensive performance, simple production process, and their output accounts for more than 90% of the current world's total carbon fiber production. The preparation technology of polyacrylonitrile-based fibers is the core of the preparation of polyacrylonitrile-based carbon fibers. At present, countries producing carbon fibers are using various methods ...

AI Technical Summary

Problems solved by technology

[0005] However, if the amount of oil is too little or the uniformity of oiling is not good, a uniform oil film cannot be formed on the surface of the monofilament, and the fiber cannot be effectively protected, which will cause adhesion or paralleling between the monofilaments; if the amount of oil is too much ,During the drying and densification process, the phenomenon of parallel filaments and sticky sticks will occur, resulting in the occurrence of broken filaments in the filament bundles

It will also cause pollution in the pre-oxidation process due to the volatilization or pyrolysis of the oil agent; in addition, if the oil agent is improperly selected and penetrates into the inner layer of the fiber, serious silicon pollution will be caused, which will make the ash content of the carbon fiber high and reduce the tensile strength of the carbon fiber. tensile strength