The chemical properties of carbon fiber is relatively stable, because the carbon allotropes (diamond, graphite, amorphous transitional carbon), depending on the form, in the air at high temperatures above 350 ℃ will be Different levels of oxidation; in an inert atmosphere isolated from air (atmospheric pressure), elemental carbon will not melt at high temperatures, but at 3800K above the high temperature without liquid directly sublimation, it can not melt spinning. Therefore, the processing method of carbon fiber products is also a certain degree of stress.

     Carbon fiber processing methods
Carbon is insoluble in various solvents and can not be solution spun. Carbon fiber can not melt method or solution direct spinning, only to organic fiber as raw material, using indirect methods to manufacture.
     The carbonization of organic matter is usually used to obtain carbon fiber, that is polymerized preoxidation, carbonized raw material monomer precursor filament pre-oxidation of a carbon fiber. The quality of carbon fiber depends on the original silk, the production process determines the pros and cons of carbon fiber. Taking polyacrylonitrile (PAN) fiber as raw material, the new technology of dry jet wet spinning and radio frequency method is gradually replacing the traditional carbon fiber preparation method (dry method and wet spinning method).
    

       Dry jet wet spinning method
    Dry jet wet spinning method that is wet and dry method, refers to the spinning liquid through the spinneret hole after the first through the air layer (also known as dry segment), and then into the coagulation bath for double diffusion, phase separation and the formation of silk method . The physical changes that occur through the air layer are conducive to the formation of fine, densified and homogenized filaments. High-density fiber body spun, smooth surface without grooves, and can achieve rapid spinning, for the production of high-performance, high-quality carbon fiber precursor. Dry jet wet spinning device is often vertical jet spinning machine, spinneret spinning liquid discharged from the spinneret through the air section (dry section) into the coagulation bath to complete the dry jet wet spinning process; and then by the guide roller, away from Bath rolls cited m yarn after post-processing PAN fibers.
    After leaving the spinneret spinneret trickle after the first air layer (dry section re-enter the coagulation bath, dry section is very short, but the coagulation phase separation and fiber structure has a significant impact on the air layer extrusion spinning solution The thin-walled solvent evaporates rapidly to form a thin and dense layer on the surface. When the fine stream enters the coagulation bath, the double diffusion rate can be suppressed. Due to the expansion effect at the exit of the spinneret, Under the flow, and then through the dry jet wet spinning positive drafts can make most of the expansion was drawn into the coagulation bath; coagulation bath with low solvent mass fraction and low temperature solidification, low solvent mass fraction ratio can be increased The mass fraction between the solvent and the trickle is poor, accelerating diffusion; low temperature can inhibit the diffusion rate, conducive to the densification and homogenization of the precipitated structure, the final spinning out of the original silk and carbon fiber surface smooth without grooves. Compared with wet spinning, dry jet wet spinning can spin higher density and no obvious core-sheath structure of raw silk, which greatly improves the tensile strength of the fiber and can produce fine-grained and homogenized high-performance carbon fiber.

We all understand the above dry jet wet spinning method? Wet and dry spun out of the original silk high strength, strong tensile, smooth, small defects, made of carbon fiber products are also high quality. For more knowledge of carbon fiber, please pay more attention to our Shusheng carbon fiber.