Glass fiber is made by melting glass at a temperature of 1300～1600℃, then spinning and melting while carbon fiber is made by preoxidizing, carbonizing and graphitizing polyacrylonitrile fiber at a high temperature of 2000～3000℃. They are same as fiber material and widely used in industrial machinery, automobile manufacturing, sports goods and other fields, so which performance is better of these two?1. Density: The density of glass fiber is about 2.5～2g/cmA3, which is lower than that of ordinary metal and almost the same as aluminum. The density of carbon fiber is only 1.6 ~ 2.0g/cmA3, almost as heavy as Borui fiber, very light.2. Tensile strength: The tensile strength of glass fiber is 2000MPa, which is dozens of times higher than that of glass with the same composition, and the tensile strength of carbon fiber is 3000MPa, which can withstand the strong external impact.3. Thermal expansion coefficient: The thermal expansion coefficient of glass fiber is 27×106/C, while the thermal expansion coefficient of carbon fiber is only -0.5×10-6C, which is almost 0, without deformation.4. Electrical properties: Glass fiber is not conductive, and it is commonly used as an insulating material in electronic devices. On the contrary, carbon fiber is a conductive material that can be used for electrodes in batteriesAs can be seen from the above, the performance of carbon fiber materials is more superior. Carbon fiber is an emerging material that began to be developed and produced with the development of industrial technology and the requirements of the military industry in the 1950s. After successively solving the production problems of raw yarn selection and high-temperature carbonization, it was gradually used in advanced civil industries.