High-modulus carbon fiber used as thermoplastic resin-based composite reinforcement body and preparation method thereof

[0025] Example 1

[0026] (1) Standard carbon fiber surface purification

[0027] The surface purification of standard modulus carbon fiber is to remove the polymer material on the fiber surface by heat treatment at 400°C for 3 minutes in a nitrogen atmosphere.

[0028] (2) Ultra-high temperature graphitization

[0029] The surface-purified carbon fiber is sent to a graphitization furnace for graphitization, using nitrogen as a protective gas, and the oxygen content in the nitrogen is 1.0 ppm; the graphitization temperature is 2150° C., and the residence time is 3 minutes.

[0030] (3) Constant current electrolytic oxidation

[0031] The current density is controlled by a DC / stabilized power supply, and the high-modified carbon fiber is subjected to continuous constant current oxidation treatment in a 5% ammonium bicarbonate electrolyte solution, and the current density is 1 mA / cm 2 , The operating temperature is 50 ℃, and then rinse with deionized water to remove the residual electroly

[0035] Example 2

[0036] (1) The surface purification of standard modulus carbon fiber is the same as in Example 1.

[0037] (2) Ultra-high temperature graphitization

[0038] The surface-purified carbon fiber is fed into a graphitization furnace for high-modulation treatment, using nitrogen as a protective gas, and the oxygen content in the nitrogen is 1.0 ppm; the graphitization temperature is 2300°C, and the residence time is 3 minutes.

[0039] (3) Constant current electrolytic oxidation

[0040] The current density is controlled by a DC / stabilized power supply, the graphitized fiber is subjected to continuous constant current oxidation treatment in 5% ammonium bicarbonate electrolyte solution, and the current density is 0.8 mA / cm 2 , Operating temperature 60℃. Then rinse with deionized water to remove residual electrolyte ions on the surface and dry.

[0041] (4) Sizing agent imidization

[0042] The carbon fiber tow was fed into the aqueous polyamic acid sizing agent and immersed

[0044] Example 3

[0045] (1) The surface purification of standard carbon fiber is the same as in Example 1.

[0046] (2) Ultra-high temperature graphitization

[0047] The surface-purified carbon fiber is sent to a graphitization furnace for high-modulation treatment, using nitrogen as a protective gas, and the oxygen content in the nitrogen is 1.0 ppm; the graphitization temperature is 2500°C, and the residence time is 3 minutes.

[0048] (3) Constant current electrolytic oxidation

[0049] The current density is controlled by a DC / stabilized power supply, and the high-modified carbon fiber is subjected to continuous constant current oxidation treatment in a 5% ammonium bicarbonate electrolyte solution, and the current density is 2 mA / cm 2 , Operating temperature 40℃. Then rinse with deionized water to remove residual electrolyte ions on the surface and dry.

[0050] (4) Sizing agent imidization

[0051] The carbon fiber tow was fed into an aqueous polyamic acid sizing agent for immer