CN-121976327-A - Method for preparing isotropic asphalt-based carbon fiber by introducing modified biological asphalt

CN121976327ACN 121976327 ACN121976327 ACN 121976327ACN-121976327-A

Abstract

The invention discloses a method for preparing isotropic asphalt-based carbon fiber by introducing modified biological asphalt, which belongs to the technical field of isotropic asphalt-based carbon fiber, adopts a co-carbonization method to eliminate defects of a single asphalt structure, the renewable acetylated biological asphalt is introduced, the coal liquefied asphalt and the acetylated biological asphalt are used as raw materials based on a co-carbonization method, the isotropic asphalt with high softening point is prepared, and the isotropic asphalt-based carbon fiber with excellent performance is prepared through melt spinning.

Inventors

DONG ZHIJUN
DONG QIXIN
TIAN YONGSHENG
GUO JIANGUANG
CONG YE

Assignees

武汉科技大学

Dates

Publication Date: 20260505
Application Date: 20260311

Claims (10)

1. The method for preparing the isotropic asphalt-based carbon fiber by introducing the modified biological asphalt is characterized by comprising the following steps of: purifying biological tar, polymerizing the purified biological tar into biological asphalt, and performing acetylation modification on the biological asphalt to obtain acetylated biological asphalt; Mixing and stirring the acetylated biological asphalt and coal liquefied asphalt under inert atmosphere, and performing a co-carbonization reaction, and cooling to obtain co-carbonized asphalt; Regulating and controlling the softening point of the co-carbonized asphalt, and preparing asphalt fibers by a melt spinning method; Pre-oxidizing the asphalt fiber to obtain pre-oxidized fiber; And (3) carrying out high-temperature carbonization treatment on the pre-oxidized fiber to obtain the isotropic pitch-based carbon fiber.
2. The method for preparing isotropic pitch-based carbon fiber by introducing modified biological asphalt according to claim 1, wherein the process of polymerizing the purified biological tar into the biological asphalt is that under the condition of stirring, the purified biological tar is heated to 200-300 ℃ and kept for 3-4 hours, and the biological asphalt is obtained after cooling; and/or the preparation process of the acetylated biological asphalt comprises the steps of dissolving the biological asphalt in tetrahydrofuran, adding acetic anhydride to carry out acetylation modification for 1-2 hours at 50-100 ℃, heating to 120-140 ℃, and cooling to obtain the acetylated biological asphalt.
3. The method for preparing isotropic pitch-based carbon fiber by introducing modified biological pitch according to claim 1, wherein the mass percentage of the acetylated biological pitch is 20-35% of the total mass of the acetylated biological pitch and coal liquefied pitch; And/or the temperature of the co-carbonization reaction is 300-340 ℃ and the time is 2-4 hours, and the co-carbonization reaction is carried out in an inert atmosphere.
4. The method for preparing isotropic asphalt-based carbon fiber by introducing modified biological asphalt according to claim 1, wherein the process of regulating and controlling the softening point of the co-carbonized asphalt is that the temperature is raised from room temperature to 300-320 ℃ at a temperature raising rate of 3-5 ℃ per minute and the temperature is kept constant under the vacuum degree of less than or equal to-0.08 MPa, and the softening point of the co-carbonized asphalt is regulated and controlled to 230-270 ℃.
5. The method for preparing isotropic pitch-based carbon fiber by introducing modified biological asphalt according to claim 1, wherein the parameter conditions of the melt spinning method comprise a spinning temperature of 260-290 ℃, a spinning pressure of 0.2-0.5 MPa and a filament collecting speed of 800-1500 rpm.
6. The method for preparing the isotropic asphalt-based carbon fiber by introducing the modified biological asphalt according to claim 1, wherein the pre-oxidation process is that in an oxygen atmosphere, the temperature is firstly increased from room temperature to 130-150 ℃ at a temperature increasing rate of 1-3 ℃ per minute, then is increased to 240-260 ℃ at a temperature increasing rate of 0.2-0.5 ℃ per minute, and is kept for 1-2 hours.
7. The method for preparing isotropic pitch-based carbon fiber by introducing modified biological asphalt according to claim 1, wherein the high-temperature carbonization treatment comprises the steps of heating the pre-oxidized fiber to 800-1000 ℃ at a heating rate of 5-10 ℃ per minute under an inert atmosphere, and preserving heat for 5-30 min.
8. The method for preparing isotropic pitch-based carbon fiber by introducing modified biological pitch as claimed in claim 1, wherein the pre-oxidizing the pitch fiber further comprises applying an applied tension to obtain drawn pre-oxidized fiber.
9. The method for preparing isotropic pitch-based carbon fiber by introducing modified biological pitch as claimed in claim 8, wherein the applied tension is 3 to 15n.
10. The isotropic pitch-based carbon fiber is characterized in that the isotropic pitch-based carbon fiber is prepared by the preparation method according to any one of claims 1-9, and has a tensile strength of 690-1700 MPa and a tensile modulus of 36-100 GPa.

Description

Method for preparing isotropic asphalt-based carbon fiber by introducing modified biological asphalt Technical Field The invention belongs to the technical field of isotropic asphalt-based carbon fibers, and particularly relates to a method for preparing isotropic asphalt-based carbon fibers by introducing modified biological asphalt. Background The asphalt-based carbon fiber is prepared from asphalt and other substances containing polycyclic aromatic hydrocarbon serving as raw materials through polymerization, spinning, stabilization and carbonization, and is divided into a general grade and a high-performance grade. The universal grade carbon fiber is prepared from isotropic pitch, also known as isotropic pitch carbon fiber, while the high performance grade carbon fiber is prepared from mesophase pitch, also known as mesophase pitch carbon fiber. Biomass-based carbon fiber is a novel carbon fiber material, which is mainly derived from biomass resources (such as cellulose, lignin and the like). The lignin has a phenylpropane structure as a main component and consists of three parts, namely p-hydroxyphenyl, syringyl and guaiacyl. In recent years, with the importance of environmental protection and sustainable development, research and application of biomass-based carbon fibers have received extensive attention. The material not only can reduce the dependence on fossil fuel, but also can reduce the cost for preparing carbon fiber, but also has the problems of low asphalt yield, low carbonization yield and the like, and in addition, the pure biomass-based material has certain problems in spinning performance, mechanical performance and the like. The universal asphalt-based carbon fiber can be used for reinforcing concrete, so that the bending toughness is improved by several times to 50 times, the structure is thinned and the steel is saved, and the universal asphalt-based carbon fiber plays an important role in friction materials, can reduce the weight of products, prolong the service life and reduce pollution. But the modulus and strength of the general asphalt-based carbon fiber are low. The high-performance asphalt-based carbon fiber can be compounded with substances such as resin, metal, carbon and the like to form a high-performance composite material, and the high-performance asphalt-based carbon fiber has the characteristics of light weight, high strength, high modulus and the like, and is widely applied to the fields of aviation, aerospace, automobile manufacturing, nuclear energy and the like. The general asphalt-based carbon fiber raw material mainly comes from petroleum asphalt and coal asphalt. Pitch often contains free carbon and solid impurities that can clog the spinning holes during spinning, and fine particles remain in the fibers as a source of breakage of the carbon fibers. For this purpose, the bitumen must be refined to remove these insoluble impurities. The refined asphalt can be spun into filaments without being directly processed, and further modulation is needed. The purpose of the preparation is to remove light components in asphalt, prevent bubbles from being generated in the spinning process to cause filament breakage, and to increase the softening point to make the molecular weight distribution uniform. The common methods for preparing the isotropic asphalt comprise a thermal shrinkage polymerization method, an air blowing method, a co-carbonization method and the like. The thermal polycondensation method refers to the polycondensation thermal reaction of asphalt under the protection of inert atmosphere and under the pressure or normal pressure at a higher reaction temperature. During the heat treatment, reactions such as dehydrogenation polycondensation and aromatization occur among asphalt molecules, and the asphalt molecules tend to form a planar condensed ring structure. The method is similar to the thermal polycondensation preparation process of the mesophase pitch, but the reaction time must be controlled in experiments to prevent the mesophase pitch from being produced after excessive thermal polycondensation. The air oxidation method is to introduce air or oxygen into the asphalt during the reaction process, and under the action of oxygen free radicals, the asphalt is subjected to polymerization reactions such as oxidation, dehydrogenation, polycondensation and the like, so as to achieve the purposes of increasing the molecular weight of the asphalt, improving the softening point of the asphalt and removing light components in the asphalt. The asphalt is oxidized in the air, the process is complex, mainly oxygen free radicals attack hydrogen atoms on aromatic hydrocarbon, and polymerization reactions such as oxidization, dehydrogenation and polycondensation are carried out, so that asphalt molecules are connected, and the structure is favorable for pre-oxidation of asphalt fibers. The softening point of the product asphalt is higher and higher along with the extension of