Carbon fiber is a fibrous carbon material with a carbon content of more than 90%. Because carbon fiber has good tensile strength and elastic modulus, excellent strength, modulus, density, corrosion resistance, fatigue resistance, etc. Materials have a wide range of applications in military, aerospace, transportation, medical equipment, industrial equipment and other fields, and have become one of the hottest composite materials.
Because the carbonization yield of PAN-based carbon fiber can reach 45%, which is higher than that of other raw materials, and the industrial process is simple and easy to operate, the conditions are easy to control, and the cost is relatively low, especially its mechanical properties, such as mild tensile strength , the elastic modulus is very good, and it has become the most widely used carbon fiber in current production.
Production process of PAN-based carbon fiber
1. Spinning: Polyacrylonitrile is made of 15% spinning solution with water solvent. The water solvent is generally sodium thiocyanate or nitric acid, dimethyl sulfoxide, etc. After wet spinning or dry jet spinning, etc. The silk process can be used to obtain PAN raw silk. The obtained PAN raw silk is woven into a cloth in a weft loom, and then sent to a pre-oxidation processor for pre-oxidation treatment.
2. Pre-oxidation treatment: The pre-oxidation treatment is carried out in two stages. The polyacrylonitrile fiber cloth is first subjected to oxidation treatment with air under the condition that the catalyst exists at 200~220 °C and tension state for 10~30min, and then at 220~220~ Continue to oxidize for 30~100min under the condition of 330℃ and tension state, so that the color of the fiber gradually changes from white to yellow, and finally becomes copper-brown. The exhaust gas generated in the pre-oxidation treatment is discharged from the treatment device, and the treated fibers are sent to the carbonization processor for carbonization treatment.
3. Carbonization treatment: The carbonization process is carried out under the protection of pure nitrogen flow , and is converted into carbon fibers with a turbostratic structure after low temperature carbonization and high temperature carbonization . The nitrogen-hydrogen decomposition gas and the carbonized decomposition gas generated in the carbonization process are successively discharged from the carbonization treatment device, and the carbonized fibers are sent to the graphite processor for machining.
4. Graphitization treatment: During graphitization treatment, carbon tube furnace is used for intermittent production. Electric current can also be used to pass through the fiber, and the electrical conductivity of the fiber itself can be used to generate heat for continuous treatment. The graphitization process is carried out under the protection of inert gas , and the graphitization is drawn under the high heat treatment temperature of 2000~3000℃.
The carbon fiber obtained by graphitization treatment is subjected to non-damage inspection and then sent to the epoxy resin treatment bath for solution infiltration treatment with dilute epoxy resin, so that the obtained unidirectional non-weft carbon fiber cloth has good lateral adhesion and is easy to operate during use. The treated non-weft fabric enters the solvent dryer to evaporate the solvent, and then passes the non-damage inspection to obtain the finished carbon fiber.
China Be-cu Prototype Material Technology Co., Ltd. has ten years of rich experience in the carbon fiber field, mainly engaged in the production and machining of carbon fiber sheets, pipes, and products. Be-cu has a complete carbon fiber product production line, manufacturing Every link in the technological process is strictly controlled, and the carbon fiber materials and products produced, whether in performance or appearance, can stand the test of customers and have been well received by customers.
