In the preparation of high strength carbon fiber model method

The present invention relates to the field of organic polymer, in particular a method for preparing high strength carbon fibers in the model, comprising the steps of: polyacrylonitrile preoxidized copolymer fiber tows within the temperature range of 180 ~ 280 ℃ under air atmosphere, using a heat treatment section 6 Ramp embodiment 60 ~ 110min, to obtain a density of the oxidized fiber 1.34 ± 0.02g / cm3, and then subjected to conventional carbonization conditions: under nitrogen, 0 to 4% at a draw ratio at 300 to 900 ℃ at low temperature carbonization 3 ± 1.5min, and the resulting fibers at high temperature carbonization 1000 ~ 1800 ℃ 3 ± 1.5min, draft ratio of -4 to 0%; wherein, in the low temperature carbonization process, the need to control the line pressure in a low temperature furnace between -5 ~ -15Pa. The present invention controls the line pressure in the low-temperature carbonization stage size, will affect the structure and properties of the pre-carbonized fiber and carbon fiber, can be improve carbon fiber structure and improve the mechanical properties by controlling the pressure of the low-temperature carbonization stage of the pipeline, thereby preparing a high strength of the model carbon fiber.