We all know that polyacrylonitrile is the polymerization of acrylonitrile. In the process of acrylonitrile polymerization, some catalysts need to be added. The raw materials are placed in water and allowed to polymerize in water. The polymer of polyacrylonitrile is insoluble in water and will precipitate. Place the polyacrylonitrile water filter. The polymerization process is also an exothermic process, so the speed of the raw materials entering the water should be slowly adjusted to make the process slow and cool down, and at the same time prevent overheating. This process is difficult to control. There are various polymerization monomers, precipitates in the water, and some uneven distribution of raw materials in the reaction vessel, which may cause polyacrylonitrile to fail to meet the required standards. This is the influencing factor of the raw materials, and the reaction mechanism of the system needs more research.
Carbon fiber cloth fiber carbon materials need to use coke containing carbon atom chain polymers. There are three commonly used carbonized polymers: cellulose (rayon), polyacrylonitrile (PAN), pitch (pitch), and polyacrylonitrile as we know it today. If the silk is uneven and contains many impurities or defects, these defects will be transmitted to the carbon fiber, so if you want to make a good carbon fiber cloth, you must have a good raw silk.
Where does the raw silk of carbon fiber cloth come from? Spinning with polyacrylonitrile. Polyacrylonitrile powder, polyacrylonitrile is first dissolved in a solvent. For confidentiality reasons, I will not tell you this solvent, dimethyl sulfoxide. Polyacrylonitrile is soluble in solvent but not in water, but this solution is infinitely miscible with water. We spray the mixture of polyacrylonitrile and solvent into the solvent, the water-soluble liquid, in a similar way to a spray spinneret. Because polyacrylonitrile is insoluble in water, it will solidify into a precursor of polyacrylonitrile when it comes into contact with water. The line is very thick, and while the solvent is dispersed in the chain, we can diffuse the solution through n layers. The concentration in this solution gradually decreases, which is conducive to the outward diffusion of the solvent. After diffusion, the original silk will enter the water stage. At this time, when the traction force is applied to take it away, the original silk slows down under the action of the traction force, and finally after densification, the silk. In order to prevent adhesion between fibers, a sizing agent is also required in the middle. This is the whole process of raw silk production. If the polyacrylonitrile raw material is not used well or the quality is uneven, there will inevitably be great defects in the raw silk spinning process.
