8 Sep, 2022 By Johny 2 Comments
What kind of material is chopped Carbon Fiber? What are its characteristics?
Chopped Carbon Fiber is made of carbon fiber filaments chopped by a fiber cutter, and its basic properties mainly depend on the properties of its raw material,Carbon Fiber filaments.Short fibers have the advantages of uniform dispersion,various feeding methods,and simple processes,and can be used in special fields that carbon fiber filaments are not suitable for.
The origin of Carbon Fiber In 1880, the American inventor Edison first carbonized bamboo fiber into filament, which was used as the light-emitting filament in the light bulb, which opened the precedent of Carbon Fiber (CF for short). The pioneer of carbon fiber used in structural materials is represented by an American company (represented in 1959, which used pitch fiber as raw material, and after thousands of Baidu carbonization at high temperature, carbon fiber with an elastic modulus of about 40GPa and a strength of about 0.7GPa was obtained; in 1965 The company also uses the same raw material to extend at a high temperature of 3000 ° C to develop a filamentous high-elasticity graphitized fiber with an elastic modulus of about 500GPa and a strength of about 2.8GPa.
In 1961, Dr. Jinto Zhaoo from the Japanese Laboratory used Polyacrylonitrile (PAN) polyacrylonitrile as raw material, after oxidation and thousands of degrees of carbonization, carbon fiber with an elasticity rate of 160GPa and a strength of 0.7GPa was obtained.
In 1962, a Japanese company (NipponCarbonCo.) used PAN as a raw material to produce low elastic modulus (L.M.) carbon fibers. Also using PAN fiber as raw material, they developed high-strength CF, with an elastic modulus of about 230GPa and a strength of about 2.8GPa. Since 1966, it has reached a monthly mass production of 1 ton. At the same time, they also developed a carbonization temperature of 2000. High elastic modulus CF above ℃, the elastic modulus is about 400GPa, and the strength is about 2.0GPa. The output of PAN-based carbon fiber reached 6,500 t/a in 1992, and by 2000 it had exceeded 10,000 t/a.
Although the demand for carbon fiber has gradually expanded, after the end of the Cold War in 1991, the use of military use has shrunk, and due to the economic depression, the balance of supply and demand has been lost, and the industry has been impacted. However, the production of Boeing’s cutting-edge B777, coupled with the expansion of civil, construction, automotive and composite applications, has made the carbon fiber industry grow slowly.
Carbon fiber is a fibrous carbon material. It is a new material with higher strength than steel, lower density than aluminum, stronger corrosion resistance than stainless steel, higher temperature resistance than heat-resistant steel, and conductive like copper, and has many valuable electrical, thermal and mechanical properties. Carbon fiber is mainly used in composite materials such as carbon fiber reinforced plastics.
Each carbon fiber is made up of thousands of smaller carbon fibers, about 5 to 8 μm in diameter. At the atomic level, carbon fibers are very similar to graphite, consisting of layers of carbon atoms arranged in a hexagonal pattern. The difference between carbon fiber and graphite is the connection between the layers. Graphite is a crystalline structure, and its interlayer connection is loose, while carbon fiber is not a crystalline structure, and the interlayer connection is irregular, which can prevent slippage and enhance material strength.
Generally, the density of carbon fiber is 1750kg/m3, the thermal conductivity is high but the electrical conductivity is low, and the specific heat capacity of carbon fiber is also lower than that of copper. When heated, the carbon fibers thicken and shorten. Although the natural color of carbon fiber is black, scientists can dye it a different color.