Carbon fiber preparation process, carbon fiber production process

Carbon Fiber Molding Process:

1. Molding method. This method is to put the carbon fiber material that has been pre-impregnated resin into the metal mold, and after pressurization, the excess glue overflows, and then cures at high temperature, and the finished product comes out after defilming, which is most suitable for making automobile parts.

2. Hand lay-up lamination method. The carbon fiber sheet soaked in glue is cut and laminated, or the layer can be brushed with resin on one side, and then thermopressed. This method is widely used because the direction, size, and thickness of the fibers can be selected at will.

It is important to note that the shape of the layup is smaller than that of the mold, so that the fibers do not deflect when pressed inside the mold.

3. Vacuum bag hot pressing method. It is laminated on a hill of molds and covered with a heat-resistant film, which is pressed by a soft pocket and cured in a hot pressure fill.

4. Winding molding method. The carbon fiber monofilament is wound on a carbon fiber shaft, which is especially suitable for making cylindrical and hollow ware.

5. Extrusion molding method. The carbon fiber is thoroughly impregnated, the resin and air are removed by extrusion, and then solidified in a furnace. This method is simple and suitable for the preparation of rod and tubular parts.

1. The carbon fiber material is wrapped with carbon cloth layer by layer, there is viscose between each layer, first pre-oxidized in the air of 200 300, and then carbonized with a high temperature of about 1000 under the protection of inert gas, and finally heated to 1500 3000 into a ridge of carbon fiber. Viscose is toxic, and carbon fiber debris is very fine, which can seriously affect health when inhaled into the lungs.

2. Carbon fiber is a new type of fiber material with high strength and high modulus fiber content of more than 95%. It is a microcrystalline graphite material made of organic fibers such as flake graphite microcrystalline stacked along the axial direction of the fiber, and obtained by carbonization and graphitization treatment. Carbon fiber is "soft on the outside and rigid on the inside", the weight is lighter than that of Jin Ziqing aluminum, but the strength is higher than that of steel, and it has the characteristics of corrosion resistance and high modulus, which is an important material in the national defense military industry and civilian use.

The way to industrialize modern carbon fiber is the precursor fiber carbonization process. The processes used to produce carbon fibers from these three types of raw fibers include stabilization (200-400 degrees Celsius air, or chemical treatment with refractory reagents), carbonization (400-1400 degrees Celsius, nitrogen) and graphitization (disturbing above 1800 degrees Celsius in an argon atmosphere). In order to improve the bonding properties of carbon fibers to composite matrices, processes such as surface treatment, sizing, and drying are required.

Another method of making carbon fiber is vapor phase growth. In the presence of a catalyst with a slow equilibrium, the mixture of methane and hydrogen can react at 1000 degrees. Production of discontinuous short carbon fibers with a maximum length of 50 cm.

Its structure differs from polyacrylonitrile-based or bitumin-based carbon fibers. Easy graphitization, good mechanical properties, high conductivity, forming interlayer compounds.

There are three kinds of carbon fiber raw materials: polypropylene fiber, viscose yarn and asphalt fiber.

1. Polypropylene-based carbon fiber has good performance and high carbonization yield, so carbon fiber made of polypropylene accounts for about most of the total carbon fiber output.

2. The carbonization yield of carbon fiber made from viscose wire is less than half, and the alkali metal content of this carbon fiber is low, which is especially suitable for ablation materials.

3. When asphalt fiber is used as raw material, the carbonization yield is as high as more than 80%, and the cost is the lowest.

According to the different use requirements and heat treatment temperature, carbon fiber is divided into flame-resistant fiber, carbon fiber and graphite fiber.

Abstract:Carbon fiber is a kind of fiber material composed of carbon elements, which has the characteristics of high strength and high modulus, and is generally made of some carbon-containing organic fiber raw materials and transported through multiple processes. The production process of carbon fiber is divided into four steps: organic fiber, fiber spinning, pre-oxidation treatment and carbonization treatment.

1. What kind of material is carbon fiber?

Fiber material is a fibrous material through the textile processing process to form a structured material, the ridge can not make fiber materials of many materials, such as common glass fiber, asbestos fiber, polyester fiber, etc., carbon fiber is also a kind of fiber material.

Carbon fiber is a special fiber composed of wild ant carbon elements, with a carbon content of more than 90%, which is a high-strength, high-modulus fiber, made of acrylic fiber and viscose fiber, and carbonized by high-temperature oxidation. Compared with other fiber materials, carbon fiber has a low density, so it has high specific strength and specific modulus, and has the characteristics of high temperature resistance, friction resistance, electrical conductivity, thermal conductivity and corrosion resistance.

Second, how carbon fiber is made.

Carbon fiber is mainly composed of carbon, but it is not directly made of carbon or graphite, but uses some carbon-containing organic fiber raw materials, and combines organic fibers with plastic resin to carbonize carbon fiber

1. Select organic fibers.

The organic fibers selected to prepare carbon fiber mainly include: polyacrylonitrile fiber, asphalt fiber, viscose filament or phenolic fiber, etc., among which polyacrylonitrile carbon fiber and asphalt carbon fiber are more commonly used. The selection of different organic fibers as raw materials will have different requirements for specific process parameters, and the properties of the prepared carbon fibers will also have certain differences.

2. Fiber spinning.

Taking polyacrylonitrile carbon fiber as an example, polyacrylonitrile is prepared with a water solvent to obtain 15% spinning solution, which is generally sodium thiocyanate or nitric acid, dimethyl sulfoxide, etc., and the precursor can be prepared through spinning processes such as wet spinning or dry jet spinning; The precursor is woven into cloth in a weft loom and then sent to a pre-oxidation processor for pre-oxidation.

3. Pre-oxidation treatment.

The pre-oxidation treatment was carried out in two stages, the polyacrylonitrile fiber cloth was first oxidized with air (or oxidation) under the conditions of catalyst presence at 200 220 and tension for 10 30 min, and continued oxidation treatment at 220 330 and tension state for 30 100 min, so that the color of the fiber gradually changed from white to yellow, and finally to copper brown. The waste 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.

4. Carbonization treatment.

The carbonization process is carried out under the protection of pure nitrogen gas flow (or vacuum), and is converted into carbon fiber with chaotic layer structure after low-temperature carbonization (300 1000) and high-temperature carbonization (1000 1800). The nitrogen and hydrogen decomposition gas and carbonization decomposition gas produced in the carbonization process are successively discharged from the carbonization treatment device.