A method to improve the strength of carbon fiber

A method of increasing the strength carbon fiber, comprising: 1) a carbon fiber is placed in an aqueous nitric acid soaked, washed with deionized water until the washing liquid carbon fibers became neutral after immersion; 2) with carbon nanotube dispersion liquid was formulated as spray, carbon nanotubes functionalized carbon nanotubes, a carbon nanotube from a hydroxylated, aminated or carboxylated carbon nanotubes in the carbon nanotube dispersion liquid is a mixture of ionic liquid and water, from the ionic liquid 1,3 - dimethylimidazolium p-toluenesulfonate, 1-butyl-3-methylimidazolium p-toluenesulfonate, 1-octyl-3-methylimidazolium chloride or 5-bromo-2-methyl-3 - one kind nitropyridine, the content of the carbon nanotube coating solution is 16 ~ 48g / L; 3) applying a positive electrostatic spraying liquid 10 ~ 40kV, the carbon fiber tow and flat ground configuration acceptor spraying liquid, then by the electrostatic spray coating was sprayed on the surface of carbon fibers. Carbon fiber tensile strength can be increased by 100%.