CN115369520B - Mesophase pitch-based carbon fiber with mixed structure and preparation method thereof - Google Patents
Mesophase pitch-based carbon fiber with mixed structure and preparation method thereof Download PDFInfo
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- CN115369520B CN115369520B CN202211010301.3A CN202211010301A CN115369520B CN 115369520 B CN115369520 B CN 115369520B CN 202211010301 A CN202211010301 A CN 202211010301A CN 115369520 B CN115369520 B CN 115369520B
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
- D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
- D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
- D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
- D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
- D01F9/15—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from coal pitch
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
- D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
- D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
- D01F9/155—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from petroleum pitch
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention discloses a mesophase pitch-based carbon fiber with a mixed structure and a preparation method thereof, wherein the microstructure of the fiber is a mixed structure in which anisotropic carbon with an easily graphitized structure and isotropic carbon with a mosaic structure are alternately and parallelly laminated, and the radial section of the fiber is irregular. The preparation method comprises the steps of mixing two raw materials of asphalt according to a certain proportion, and obtaining the spinnable mesophase asphalt with isotropic matrix containing mesophase macrospheres through high-temperature polymerization reaction, wherein the molecular weight difference between isotropic components and anisotropic components in the spinnable asphalt is small. And (3) carrying out melt spinning on the asphalt to obtain continuous asphalt fibers, and further carrying out non-melting and high-temperature carbonization to obtain asphalt-based carbon fibers. The carbon fiber has higher tensile strength and elastic modulus compared with the general-grade pitch-based carbon fiber and higher elongation at break compared with the mesophase pitch-based carbon fiber. Has important significance in optimizing the performance of the mesophase pitch-based carbon fiber, improving the impact resistance and the like.
Description
Technical Field
The invention relates to the field of carbon fibers, in particular to a manufacturing method of pitch-based carbon fibers.
Background
Pitch-based carbon fibers are classified into general-grade pitch-based carbon fibers and high-performance grade mesophase pitch-based carbon fibers. The general-purpose carbon fiber is usually formed by taking isotropic spinnable asphalt as a raw material for spinning and heat treatment, the isotropic spinnable asphalt is generally optical isotropic asphalt formed by taking purified asphalt with a softening point of 80-150 ℃ as a raw material and realizing molecular crosslinking of asphalt molecules through oxygen bridges under the oxidation condition, the softening point is optically isotropic under a polarizing microscope at 250-285 ℃, and the isotropic spinnable asphalt is generally called isotropic spinnable asphalt or isotropic asphalt for short. The high-performance intermediate phase pitch-based carbon fiber is formed by taking spinnable intermediate phase pitch as a raw material and carrying out melt spinning and heat treatment, and the spinnable intermediate phase pitch is also obtained by taking pitch with a softening point of 80-150 ℃ as a raw material and carrying out polymerization reaction under the inert atmosphere condition to synthesize the high-performance intermediate phase pitch-based carbon fiber. The raw material asphalt is polymerized to increase the size of aromatic hydrocarbon molecules, and the molecules are orderly piled up to form aromatic hydrocarbon molecular clusters under the action of Van der Waals force, wherein the molecular clusters have the characteristic of crystal structure. After further heat treatment to remove small molecules in the system, the molecular clusters are fused to form a mesophase structure, and the structure has the characteristic of liquid crystal and is called mesophase pitch. Optically anisotropic under a polarizing microscope, and is therefore also referred to as anisotropic pitch. Spinnable grade mesophase pitch is also known as spinnable mesophase pitch.
The mesophase pitch retains the inherent directional arrangement structure in the liquid crystal molecules by melt spinning, and the crystal is preferentially oriented along the fiber axis after high-temperature graphitization treatment to form a graphite structure L a And L is equal to c The size is large, so the composite material has ultrahigh modulus, ultrahigh axial heat conduction and electric conduction performance, and is widely applied to the high technical field of which the performance of polyacrylonitrile-based carbon fibers is not the same as that of aerospace, electronic equipment and the like. The molecular lamellar L is due to the highly preferential orientation of the molecules along the fiber axis a And L is equal to c The size is large, and the defects of low elongation at break and poor radial shearing resistance of the mesophase pitch-based carbon fiber are formed by the characteristics; in addition, in the high mesophase content pitch spinning process, because large lamellar molecules are highly oriented, the radial section of the carbon fiber is extremely easy to form a radiation structure, and when the high-temperature treatment is carried out, the regular lamellar molecules are arranged to generate the conduction of shrinkage stress, and the fiber is split along the axial direction, so that the mechanical property of the carbon fiber is directly influenced.
In actual production, the difficulty of controlling the microscopic section of the mesophase pitch-based carbon fiber not to generate radial radiation type structure and axial non-splitting is great, so that the occurrence of the situation is caused by a plurality of factors.
Chinese patent CN 102031593A describes a method for producing pitch-based carbon fibers by mixing and spinning mesophase pitch with isotropic pitch, in order to reduce the high orientation of pitch molecules and to exhibit cleavage by radiation-type structures, thereby improving the performance of the carbon fibers. Although the two kinds of asphalt with similar softening points are mixed, the intermediate phase asphalt with a crystal structure and the isotropic asphalt with an amorphous structure are difficult to uniformly mix, and a mixture with consistent physical properties is difficult to form after melting, so that the viscosity difference is large, and the spinning stability is poor.
Chinese patent CN 109112671A, in order to control the microstructure of the mesophase pitch-based carbon fiber, avoid axial splitting of the mesophase pitch-based carbon fiber, by adjusting the content of mesophase, a spinnable pitch with low content of mesophase is prepared, and the order of pitch molecular arrangement is reduced. However, when the asphalt with low mesophase content is spun, the anisotropic asphalt with larger density is easy to settle in the spinning process, phase separation is generated, and the smooth spinning is affected, so that strong stirring is adopted during the spinning, and the phenomenon that the spinning is affected due to the occurrence of phase separation is avoided. Meanwhile, the asphalt has high light component content, low oxidation activity and long oxidation time, and needs 10-30 hours, so that industrial production is difficult to realize. The purpose of the patent is only to reduce the radial section of the mesophase pitch-based carbon fiber to present a radial structure and to axially split.
Disclosure of Invention
The invention aims to: the invention aims to provide a mesophase pitch-based carbon fiber with a mixed structure and basic characteristics of high modulus, high electric conductivity and high heat conduction and also high elongation at break impact resistance and a preparation method thereof.
The technical scheme is as follows: the mesophase pitch-based carbon fiber of the mixed structure of the invention has the microstructure of: the radial section is an irregular mixed structure with anisotropic carbon which is easy to graphitize and isotropic carbon which is inlaid in the axial direction alternately and parallelly laminated.
Unlike the patents mentioned in the background art, the mesophase pitch-based carbon fiber of the present invention is free from splitting in the axial direction while achieving both high tensile strength and high elongation at break. In order to achieve the above purpose, the invention synthesizes mesophase pitch by taking two kinds of pitch with different molecular weights and polymerization reactivity as raw materials, has small molecular weight difference between isotropic components and anisotropic components, and has the following characteristics: isotropy is taken as a matrix under a polarizing microscope, and the matrix contains anisotropic fused big spheres; softening point 245-255 ℃; quinoline insoluble QI < 15%, toluene insoluble TI > 80%, n-heptane insoluble HI > 90%. The microstructure of the radial section of the formed mesophase pitch-based carbon fiber does not need special control, and the section is in an irregular structure; the axial direction is a mixed structure of graphitized carbon and mosaic structure carbon which are alternately and orderly laminated and arranged, and the composite structure is not split. Has the basic characteristics of high modulus, high electric conductivity and high heat conduction of mesophase pitch-based carbon fibers, the carbon fiber also has the characteristic of high elongation at break and impact resistance of the general asphalt-based carbon fiber.
The preparation method of the mesophase pitch-based carbon fiber with the mixed structure comprises the following steps:
step 1, extracting high-temperature coal tar pitch by using benzene or toluene solvent to obtain soluble component pitch as a raw material A, wherein the soluble component pitch comprises BS or TS; coal-based hydrogenated asphalt or petroleum asphalt PA without quinoline insoluble matter QI is used as a raw material B;
step 2, mixing the raw material A and the raw material B to obtain a spinnable mesophase pitch raw material;
step 3, carrying out high-temperature polymerization on the spinnable mesophase pitch raw material to obtain spinnable mesophase pitch;
step 4, fully melting spinnable mesophase pitch, feeding the melt into a spinning assembly through a nitrogen pressure type or metering pump, and drawing the melt through a winding machine to obtain pitch fibers;
and 5, performing air pre-oxidation, non-melting and carbonization on the asphalt fiber to obtain the mesophase asphalt-based carbon fiber.
In the step 1, the high-temperature coal tar pitch is subjected to extraction treatment, wherein the softening point of the soluble component pitch is 70-90 ℃, and the ash content is 0; the softening point of coal-based hydrogenated asphalt or petroleum asphalt PA without quinoline insoluble matter QI is 80-150 ℃ and H/C is 0.80-0.95.
In step 2, the raw material A and the raw material B are mixed according to the proportion of 1:0.8-1.5.
Further, in the step 3, the high-temperature polymerization reaction temperature is 380-450 ℃ and the reaction time is 5-10 h.
Further, in step 3, the molecular weight difference between the isotropic component and the anisotropic component of the spinnable mesophase pitch formed is small, and the mesophase pitch is characterized by the fact that it is displayed by a cold-state polarization microscope without intense stirring: isotropy is that the parent body contains mesophase big spheres; softening point (ring and ball method): 245-255 ℃; group composition: quinoline insoluble QI < 15%, toluene insoluble TI > 80%, n-heptane insoluble HI > 90%.
Further, in the step 4, the spinning temperature is 300-340 ℃, the spinning pressure is 0.5-5 MPa, the drafting speed is 200-400 m/min, and the diameter of the asphalt fiber is 10-15 mu m.
Further, in the step 5, the pre-oxidation temperature is 250-320 ℃, the oxidation time is 1-5 hours, and the oxidation atmosphere is air; the carbonization temperature is 800-1200 ℃, the carbonization time is 1-2 h, and the carbonization atmosphere is high-purity nitrogen.
The principle of the invention: the invention obtains the mesophase pitch-based carbon fiber which has an anisotropic carbon with a random structure in the radial direction and an isotropic carbon orderly laminated mixed structure with an easily graphitized structure in the axial direction, has the general characteristics of the mesophase pitch-based carbon fiber and has the characteristic of higher elongation at break, and has obvious differences from the mechanical property index and the axial microstructure of the mesophase pitch-based carbon fiber in the general sense. In order to achieve the aim, the invention optimizes and improves the molecular composition of the raw materials and the mesophase pitch, and the preparation processes of the raw materials, synthesis, spinning, oxidation, non-melting, carbonization and the like are further described.
The raw materials of the conventional spinnable mesophase pitch are usually petroleum pitch and hydrogenated high-temperature coal pitch for high-temperature polymerization reaction, or are synthesized by catalyzing Friedel-Crafts alkylation reaction of single-component naphthalene, anthracene and the like of high-temperature coal tar through Lewis acid/protonic acid, and the raw materials are single pitch or pitch precursors. The mesophase pitch obtained by taking petroleum pitch and coal pitch as raw materials has a plurality of control factors and is complex in the spinning process, so that a radial radiation type and axial splitting structure is easily obtained, and the strength of the carbon fiber is influenced. In addition, the polyaromatic hydrocarbon molecular sheet is too complete, so that the anisotropic material has obvious characteristics, and the fiber has the defects of low elongation at break and poor radial shear strength while having high modulus, high electric conductivity and high heat conduction. The invention takes two kinds of asphalt with similar molecular structures but obvious difference in molecular weight and polymerization activation energy as raw materials, and the two kinds of asphalt have sequence in the time and temperature space of the reaction sequence.
The raw material A has a small molecular weight and is not subjected to hydrogenation treatment, and compared with the raw material B, the raw material A has a severe condition for activating molecular free radicals and is a part which is difficult to carry out polymerization reaction. In the beginning of synthesis, the possibility of polymerization reaction between raw material A and raw material A is low, the raw material A basically plays a role in inhibiting polymerization reaction, but as time goes on and small molecular weight molecules of the system are discharged, the overall molecular weight of the system is increased, the raw material A is synthesized with larger molecules X/Y … generated by previous synthesis of B and B, the total participation degree is low, the molecular weight increase range is small, and finally an isotropic component with larger molecular weight in spinnable asphalt is formed. The existence of the raw material A has great significance in controlling the polymerization reaction speed of the system, avoiding the formation of ultra-macromolecules and controlling the QI content, and has important help in basically controlling the axial splitting of the mesophase pitch-based carbon fiber.
The starting molecular weight of the raw material B is larger than that of the raw material A, the molecular structure of the raw material B is provided with a cycloalkyl group and a small amount of short side chains, the polymerization reaction activation energy is low, and the raw material B is a main body for starting to form macromolecular aromatic hydrocarbon, but under the control of the raw material A, the reaction speed is low, oversized molecules are not easy to form, and finally the anisotropic component in the spinnable asphalt is formed. The anisotropic component has a relatively small molecular weight and a narrow molecular weight distribution, so that the final spinnable bitumen QI content is very low, mainly a soluble intermediate phase (TI-QS) component. Because the spinnable asphalt system contains more isotropic components with larger molecular weight, the asphalt shows the characteristic of containing anisotropic globules in isotropic parent phase under a polarizing microscope.
Despite the above characteristics, the spinnable bitumen system is sufficiently freed of small molecule components. Firstly, the HI content of the heptane insoluble matter is high, namely the HS content of the heptane soluble matter is small, which indicates that the content of aromatic hydrocarbon components with small molecular weight in the system is low; the low QI content indicates that the content of the components with larger molecular weight in the system is also low. I.e. mesophase pitch, has a narrow molecular weight distribution, and the anisotropic component of large molecular weight and the isotropic component of small molecular weight are not significantly different. Secondly, the TI content of the group composition is higher, TI data can be used as a quantization index of the intermediate phase content, the TI component can be divided into three parts in the intermediate phase, and the TI component has enough molecular size, namely has stacking conditions, but is isotropic in a polarizing microscope; secondly, molecular clusters and micro domains are formed by stacking, but the resolution of a polarizing microscope cannot be observed, and the molecular clusters and micro domains are also shown to be isotropic; and thirdly, anisotropic parts such as small spheres, large spheres, wide areas, streamline and the like which can be observed by a polarized light microscope. The TI data can be used as a reference to the anisotropic content data obtained by the polarizing microscope. A high TI-QS content also indicates a high component content with moderate molecular weight and a narrow molecular weight distribution.
Because the spinnable mesophase pitch has a low softening point, the spinning temperature is low, the possibility of polymerization reaction of the pitch in the spinning process is avoided, and continuous stable spinning or formation of air holes in fibers is not affected by cracking of light components.
The molecular weight of the anisotropic component group is larger than that of the isotropic component group, and only when the molecular weight of the isotropic component reaches a certain value, the anisotropic component is converted. In the present invention, the isotropic component having a relatively large molecular weight has a smaller molecular weight than the anisotropic component having a relatively small molecular weight, but the difference between them is small. Therefore, the molecular weight distribution of the anisotropic phase and the isotropic phase is narrow, the asphalt is not easy to generate sedimentation and separation of the two phases due to density difference, the smooth spinning is affected, and the spinning performance is good.
The molecular weight distribution of the asphalt fiber obtained by spinning is narrow, and isotropic components with low oxidation reactivity and small molecular weight hardly exist, so that the asphalt fiber has high oxidation reactivity, the oxidation temperature is 300-320 ℃, the asphalt fiber belongs to the conventional range, and no obstacle exists in oxidation stabilization.
Due to the characteristic of small overall molecular weight of the mesophase pitch, the arrangement of the spun pitch fiber crystals is not quite regular, and the phenomena of radial radiation type structure and axial splitting can not occur after carbonization.
In the carbonization process, because the free radicals of the intermediate phase part with larger molecular weight in the system are activated first, carbonization polycondensation reaction is started first, and therefore, the phenomenon of preferential polycondensation among macromolecules of the intermediate phase part occurs, in the carbonization polycondensation process, the macromolecules are subjected to migration rearrangement to form anisotropic carbon components which are easy to graphitize in a microstructure, and the structure determines the basic characteristics of high strength, high modulus, high electric conduction, high heat conduction, low radial shear strength and low elongation at break of the carbon fiber. As the carbonization temperature increases, the isotropic component molecular radicals are also activated, proceeding with the carbonization polycondensation reaction, but after the anisotropic component macromolecules complete the polycondensation reaction. Since relatively small isotropic component molecules require higher free radical activation temperatures than anisotropic component molecules, the polycondensation temperature is high for mutual carbonization, resulting in a fast polycondensation reaction rate and failure to form a broad mesophase. The carbon layer is discontinuous, and forms carbon particles with embedded structure, namely, the carbon particles generate isotropic carbon components in microstructure. Unlike available graphitized ordered carbon layer, the isotropic carbon has no shrinkage and concentrated stress conduction, and has microscopic structure to prevent the radial shrinkage of carbon fiber, counteract the shrinkage stress and avoid radial radiation and axial splitting. The mechanical structure also plays a role in absorbing impact, so that the whole fiber has the characteristics of high elongation at break and high radial shear strength, but the elastic modulus of the carbon fiber is reduced.
From the tensile strength index, the intermediate phase pitch-based carbon fiber of the mixed structure is basically similar to the intermediate phase pitch-based carbon fiber subjected to radial radiation and axial splitting, and the intermediate phase pitch-based carbon fiber of the radiation type splitting structure reduces the tensile strength due to the splitting structure, but meanwhile, the anisotropic carbon with complete molecular arrangement and high order degree can improve the tensile strength; the isotropic carbon of the mosaic structure in the mixed structure reduces the tensile strength, but the complete radial section is favorable for improving the tensile strength, so that the intermediate phase pitch-based carbon fiber of the mixed structure and the radial radiation intermediate phase pitch-based carbon fiber have no great difference in tensile strength performance.
The beneficial effects are that: compared with the prior art, the invention has the following remarkable advantages: the invention mixes two kinds of raw material asphalt with similar molecular structures and different molecular weight and polymerization reactivity according to a certain proportion, obtains spinnable mesophase asphalt with isotropic matrix containing mesophase macrospheres through high-temperature polymerization reaction, has small molecular weight difference between isotropic components and anisotropic components in spinnable asphalt, and obtains the mesophase asphalt-based carbon fiber with a mixed structure after melt spinning and heat treatment, wherein the microstructure is a mixed structure with random radial sections, and anisotropic carbon with an axial graphitizable structure and isotropic carbon with an embedded structure are alternately and parallelly laminated. The carbon fiber has no splitting in the axial direction, has higher tensile strength and elastic modulus compared with the general-purpose pitch carbon fiber, has higher elongation at break compared with the mesophase pitch-based carbon fiber, and expands the application field of the mesophase pitch-based carbon fiber.
Drawings
FIG. 1 is a diagram of a spinnable asphalt polarized microscope lens of the present invention having 60% mesophase;
FIG. 2 is a diagram of a spinnable asphalt polarized microscope lens of the present invention having 40% mesophase;
FIG. 3 is a diagram of a spinnable asphalt polarized microscope lens of the present invention having 85% mesophase;
FIG. 4 is a diagram of a spinnable asphalt polarized microscope lens of the present invention containing 100% mesophase;
FIG. 5 is a diagram of a spinnable asphalt polarized microscope lens of the present invention containing 90% mesophase;
FIG. 6 is a diagram of a spinnable asphalt polarized microscope lens of the present invention containing 70% mesophase;
FIG. 7 is an SEM image of mesophase pitch-based carbon fibers of example 1 of the present invention;
FIG. 8 is an SEM image of mesophase pitch-based graphite fibers of example 1 of the present invention;
FIG. 9 is an SEM image of mesophase pitch-based carbon fibers of comparative examples 1-2 of the present invention;
FIG. 10 is an SEM image of mesophase pitch-based carbon fibers of comparative examples 1-3 of the present invention;
fig. 11 is an SEM image of mesophase pitch-based graphite fibers in example 2 of the present invention.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings.
Example 1
Purifying asphalt C by high-temperature coal tar, and extracting by toluene to obtain toluene soluble TS serving as a raw material A. The high-temperature coal tar purified asphalt C is subjected to hydrogenation treatment to obtain coal-based hydrogenated asphalt, and quinoline insoluble components are further extracted and removed to obtain a raw material B 1 . Simultaneously comprises the following steps:
(1) Raw materials A and B 1 As raw materials, the mixing ratio of the two asphalts is A to B 1 =1:1; analytical data for the two bitumens are shown in Table 1. After the two bitumens are mixed by melting, polymerization is carried out at a high temperature of 430 ℃ for 8 hours, and spinnable mesophase pitch with a softening point of 245 ℃ is obtained, and the analytical data of the mesophase pitch are shown in Table 2. The polarized light micrograph is shown in figure 1, and the polarized light microscope shows that the spinnable asphalt prepared in the embodiment has the mesophase content of about 60 percent, is an optical anisotropic fused big sphere with different diameters, and is more uniformly dispersed in an optical isotropic asphalt mother solution; in the isotropic mother liquor, some anisotropic microspheres can be seen, and the difference between the isotropic component and the anisotropic component is small, and the molecular weight distribution is narrow.
(2) Continuous spinning is carried out by a nitrogen pressure type 6-hole spinning machine, and the specific steps are as follows: adding 200g of spinnable asphalt into a stainless steel melt pipe with the outer diameter of 40mm, the inner diameter of 35mm and the height of 400mm, heating and melting through an external copper sleeve, setting the wall temperature to 310 ℃ and setting the internal asphalt temperature to 305 ℃; the diameter of the spinneret plate is 0.2mm, and the length-diameter ratio is 2. And continuously heating and melting for 10 hours, and then spinning. Nitrogen is pumped into the melting pipe, the pressure is kept between 0.2 and 0.3MPa, the drafting speed of the winding machine is 300m/min, and continuous and stable spinning is carried out for 5 hours until spinning is completed. Under the condition of no stirring in the melting pipe, the spinning asphalt is uniform in upper and lower materials and has no anisotropic component sedimentation and delamination.
(3) The intermediate phase asphalt fiber is oxidized and not melted under the condition that air is introduced into a non-melting furnace, wherein the temperature rising rate is as follows: the room temperature is 5 ℃/min to 220 ℃, and the temperature is kept constant for 1h at 220 ℃; keeping the temperature of 220-300 ℃ at 1 ℃/min and the temperature of 300 ℃ for 1h to obtain the non-melting fiber. The oxidation reaction activity in the oxidation process is high, and the oxidation speed is high.
(4) Carbonizing the unmelted fiber under nitrogen atmosphere, wherein the temperature rising rate is that the room temperature is 2 ℃/min at the temperature of 700 ℃ and 5 ℃/min at the temperature of 700-1000 ℃, and the carbon fiber with the average diameter of 11 mu m is obtained after the temperature is kept at 1000 ℃ for 1 h.
Fig. 7 shows that the radial cross-section of the 1000 ℃ heat-treated carbon fiber is regular in morphology, fine in crystallite size, uniform in structure and free from cleavage. In order to further observe the microscopic mixed structure, the carbon fiber was graphitized at 2600 ℃, and the obtained graphite fiber showed a mixed structure in which an anisotropic graphitized carbon layer and an isotropic carbon layer of a mosaic structure were orderly stacked as shown in fig. 8. The tensile strength, elastic modulus and elongation at break of the carbon fiber are 1530MPa, 170GPa and 0.9 percent respectively. The tensile strength and the elastic modulus are far higher than those of the general-grade pitch-based carbon fiber, the elongation at break is far higher than that of the mesophase pitch-based carbon fiber, and the carbon fiber is similar to the general-grade pitch-based carbon fiber.
Comparative examples 1 to 1
(1) The mixing ratio of the two asphalts of example 1 was adjusted to A to B 1 =1:0.5; the raw materials are polymerized at a high temperature of 430-440 ℃ for 10 hours to obtain mesophase pitch with a softening point of 240 ℃, the polarized light micrograph is shown in figure 2, the mesophase content of the pitch is about 40%, the pitch is optically anisotropic big spheres with different diameters, the pitch is uniformly dispersed in an optically isotropic pitch mother solution, and the analytical data of the mesophase pitch are shown in table 2.
(2) 200g of mesophase pitch having a mesophase content of 40% was continuously spun in a nitrogen-pressure type 6-hole spinning machine as in example 1, and was heated and melted for 5 hours, followed by spinning. The melt pipe keeps the pressure at 0.3MPa, the drafting speed of the winding machine is 300m/min, the spinning is basically stable before 30min, but the yarn breakage starts to occur after 30min, the material dripping occurs in the spinneret holes, and the spinneret plate is polluted. Due to the excessively high isotropic phase ratio, the isotropic phase and the anisotropic phase generate a density difference, resulting in delamination of the two-phase component and discontinuous spinning. Collecting part of asphalt fibers, carrying out non-melting treatment at 260-300 ℃, and carrying out adhesion on the asphalt fibers, wherein the oxidation activity is low and the reaction is insufficient.
It was revealed that the molecular weight of the raw material A was small, and it was not a main component for synthesizing mesophase pitch, and that the excessive raw material A hindered the polymerization reaction, and the mesophase could not be rapidly formed during the synthesis and the continuous stable spinning could not be performed, although the polymerization time was 2 hours more than in example 1.
Comparative examples 1 to 2
(1) As raw material A, B in example 1 1 Is used as raw material A and B 1 Polymerization at 430 ℃ for 6h gave mesophase pitch with a softening point of 265 ℃ and a mesophase content of about 85% as shown in fig. 3 for a polarized micrograph, and the mesophase pitch analysis data are shown in table 2. Unlike example 1, the optically isotropic macrospheres were uniformly dispersed in the optically anisotropic asphalt mother liquor, and phase inversion occurred. While many anisotropic globules can be seen in the isotropic globules, the mesophase content is not sufficient to be determined with a polarizing microscope alone.
(2) Continuously spinning mesophase pitch in a nitrogen pressure type 6-hole spinning machine in the same manner as in example 1, carrying out melt spinning at 330 ℃, wherein the spinning pressure is 0.4-0.5 MPa, the drafting speed of a winding machine is 300m/min, the pitch spinning is stable, collecting pitch fibers to be subjected to non-melting treatment at 300 ℃, carbonizing the non-melting fibers at 1000 ℃ under the condition of nitrogen atmosphere, and keeping the temperature for 1h to obtain carbon fibers with the average diameter of 18 mu m.
The microstructure of the section of the carbon fiber sample is shown in fig. 9, the fiber structure is uniform, the fiber is split in the axial direction, the splitting angle is small, and the crystallite growth is obvious. The tensile strength, elastic modulus and elongation at break of the carbon fiber are 1380MPa, 345GPa and 0.4 percent respectively. The carbon fiber has no mixed structure in the axial direction, low elongation at break and general characteristics of mesophase pitch-based carbon fiber.
Comparative examples 1 to 3
(1) Raw material B as in example 1 1 Is used as raw material and is high at 440 DEG CPolymerization reaction at temperature for 5h to obtain mesophase pitch with softening point of 280 ℃ and analysis data of mesophase pitch shown in table 2, wherein a polarized micrograph is shown in fig. 4, and the mesophase content of pitch is 100%, which is a wide-area structure with optical anisotropy.
(2) Continuously spinning the mesophase pitch with the mesophase content of 100% in a nitrogen pressure type 6-hole spinning machine which is the same as that of the embodiment 1, carrying out melt spinning at 340 ℃, wherein the spinning pressure is 0.3-0.4 MPa, the drafting speed of a winding machine is 300m/min, the pitch spinning is stable, collecting pitch fibers, carrying out non-melting treatment at 300 ℃, carbonizing the non-melting fibers at 1000 ℃ under the nitrogen atmosphere, and keeping the temperature for 1h to obtain carbon fibers with the average diameter of 14 mu m.
The microstructure of the cross section of the carbon fiber sample is shown in fig. 10, fibers are obviously split, the splitting angle is large, the crystallite growth is obvious, the crystallite size is large, and the preferred crystal orientation is obvious. The tensile strength, elastic modulus and elongation at break of the carbon fiber are 1250MPa, 350GPa and 0.36 percent respectively.
Comparative examples 1 to 4
(1) Starting material B 1 And raw material C purified coal pitch as raw material, the mixing ratio of two kinds of pitch is B 1 C=2:1; the analytical data of the raw material C asphalt are shown in Table 1. After the two kinds of asphalt are mixed by melting, the two kinds of asphalt are polymerized for 6 hours at 430 ℃ to obtain intermediate phase asphalt with a softening point of 310 ℃, the analysis data of the intermediate phase asphalt are shown in table 2, the polarized light micrograph is shown in fig. 5, the intermediate phase content of the spinnable asphalt prepared in the embodiment is about 90%, the spinnable asphalt is of an optically anisotropic bulk phase structure, and the isotropic asphalt component is relatively small.
(2) 200g of mesophase pitch with the mesophase content of 90% is continuously spun in a nitrogen-pressure type 6-hole spinning machine of the same kind as in example 1, and melt-spun at 370-380 ℃ under the spinning pressure of 1MPa, the drawing speed of a winding machine is 200m/min, the viscosity of the spinning pitch is high, and continuous drawing and fiber forming cannot be performed. Because asphalt has higher reactivity at the temperature of more than 360 ℃, the asphalt can be subjected to rapid polycondensation reaction to generate larger polycyclic aromatic hydrocarbon units, and further, the excessive polycondensation is carried out, so that the viscosity of a system is increased, the fluidity of a mesophase component is reduced, and the melt drawing into filaments cannot be carried out.
Component C and component B 1 The molecular weight is substantially the same, and the component C does not inhibit the polymerization rate as the component A.
Example 2
And (3) carrying out reduced pressure distillation on the low ash, low nitrogen and low sulfur catalytic cracking slurry oil, and polymerizing for 7h under the condition of 410 ℃/0.6MPa to obtain the polycondensed asphalt. Further removing light components and quinoline insoluble substances from the polycondensed asphalt to obtain a raw material B 2 。
(1) Raw materials A and B 2 As raw materials, the mixing ratio of the two types of asphalt is 1:1; the analytical data for the two bitumens are shown in Table 1. After the two kinds of asphalt are mixed by melting, the two kinds of asphalt are polymerized for 6 hours at a high temperature of 430 ℃ to obtain spinnable asphalt with a softening point of 250 ℃, the analysis data of mesophase asphalt are shown in table 2, the polarized light micrograph of the spinnable asphalt is shown in fig. 6, the content of mesophase of the spinnable asphalt prepared in the embodiment is about 70%, and the spinnable asphalt is an optical anisotropic big sphere with different diameters and is more uniformly dispersed in an optical isotropic asphalt mother solution; unlike example 1, anisotropic globules are less visible in the isotropic masterbatch, and the mesophase pitch has a slightly greater molecular weight difference between the anisotropic and isotropic components than in example 1, and a molecular weight B compared to the petroleum pitch 2 Coal-based hydrogenated asphalt B 1 The molecular weight is large.
(2) Continuous spinning is carried out by a nitrogen pressure type 6-hole spinning machine in the embodiment 1, and the specific steps are as follows: adding 200g of spinnable asphalt into a stainless steel melt pipe with the outer diameter of 40mm, the inner diameter of 35mm and the height of 400mm, heating and melting through an external copper sleeve, setting the wall temperature to 310 ℃ and setting the internal asphalt temperature to 305 ℃; the diameter of the spinneret plate is 0.2mm, and the length-diameter ratio is 2. And continuously heating and melting for 10 hours, and then spinning. Nitrogen is pumped into the melting pipe, the pressure is kept between 0.2 and 0.3MPa, the drafting speed of the winding machine is 300m/min, and continuous and stable spinning is carried out for 5 hours. The spinning asphalt is uniform in materials on the asphalt without stirring in the melting pipe, and sedimentation and layering can not occur.
(3) The intermediate phase asphalt fiber is oxidized and not melted under the condition that air is introduced into a non-melting furnace, wherein the temperature rising rate is as follows: the room temperature is 2 ℃/min to 220 ℃, and the temperature is kept constant for 1h at 220 ℃; keeping the temperature of 220-300 ℃ at 1 ℃/min and the temperature of 300 ℃ for 1h to obtain the non-melting fiber.
(4) Carbonizing the unmelted fiber under nitrogen atmosphere, wherein the temperature rising rate is that the room temperature is 2 ℃/min at the temperature of 700 ℃ and 5 ℃/min at the temperature of 700-1000 ℃, and the carbon fiber with the average diameter of 11 mu m is obtained after the temperature is kept at 1000 ℃ for 1 h.
The carbon fiber obtained by the embodiment after heat treatment at 1000 ℃ has regular appearance, uniform structure and no splitting. The tensile strength, elastic modulus and elongation at break of the carbon fiber are 1580MPa, 165GPa and 0.96 percent respectively. In order to further observe the microscopic mixed structure, the carbon fiber was graphitized at 2600 ℃, and as shown in fig. 11, SEM pictures can see a mixed structure in which an anisotropic graphitized carbon layer and an isotropic carbon layer of a mosaic structure are orderly stacked.
TABLE 1 data analysis of raw asphalt
TABLE 2 data analysis of spinnable mesophase pitch
Claims (5)
1. The preparation method of the mesophase pitch-based carbon fiber of the mixed structure is characterized in that the microstructure of the mesophase pitch-based carbon fiber of the mixed structure is as follows: a mixed structure in which anisotropic carbon with an irregular radial section and an easily graphitized structure and isotropic carbon with a mosaic structure are alternately and parallelly laminated in the axial direction; the preparation method of the mesophase pitch-based carbon fiber of the mixed structure comprises the following steps:
step 1, extracting high-temperature coal tar pitch by using benzene or toluene solvent to obtain soluble component pitch as a raw material A, wherein the soluble component pitch comprises BS or TS; coal-based hydrogenated asphalt or petroleum asphalt PA without quinoline insoluble matter QI is used as a raw material B;
step 2, mixing the raw material A and the raw material B according to the proportion of 1:0.8-1.5 to obtain a spinnable mesophase pitch raw material;
step 3, carrying out high-temperature polymerization on the spinnable mesophase pitch raw material to obtain spinnable mesophase pitch; the reaction temperature of the high-temperature polymerization is 380-450 ℃ and the reaction time is 5-10 h;
step 4, fully melting spinnable mesophase pitch, feeding the melt into a spinning assembly through a nitrogen pressure type or metering pump, and drawing the melt through a winding machine to obtain pitch fibers;
and 5, performing air pre-oxidation, non-melting and carbonization on the asphalt fiber to obtain the mesophase asphalt-based carbon fiber.
2. The method for preparing the mesophase pitch-based carbon fiber of a mixed structure according to claim 1, wherein in the step 1, the high-temperature coal tar pitch is subjected to extraction treatment, the softening point of the pitch of a soluble component is 70-90 ℃, and the ash content is 0; the softening point of coal-based hydrogenated asphalt or petroleum asphalt PA without quinoline insoluble matter QI is 80-150 ℃ and H/C is 0.80-0.95.
3. The method for preparing mesophase pitch-based carbon fibers of a mixed structure according to claim 1, wherein in step 3, the molecular weight difference between the isotropic component and the anisotropic component of the spinnable mesophase pitch is small, and the mesophase pitch is characterized by showing in a cold-state polarization microscope without strong stirring: isotropy is that the parent body contains mesophase big spheres; softening point measured by ring and ball method: 245-255 ℃; group composition: quinoline insoluble QI < 15%, toluene insoluble TI > 80%, n-heptane insoluble HI > 90%.
4. The method for preparing the mesophase pitch-based carbon fiber of a mixed structure according to claim 1, wherein in the step 4, the spinning temperature is 300-340 ℃, the spinning pressure is 0.5-5 mpa, the drawing speed is 200-400 m/min, and the pitch fiber diameter is 10-15 μm.
5. The method for preparing the mesophase pitch-based carbon fiber of a mixed structure according to claim 1, wherein in the step 5, the pre-oxidation temperature is 250-320 ℃ and the oxidation time is 1-5 hours, and the oxidation atmosphere is air; the carbonization temperature is 800-1200 ℃, the carbonization time is 1-2 hours, and the carbonization atmosphere is high-purity nitrogen.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4534850A (en) * | 1980-11-19 | 1985-08-13 | Toa Nenryo Kogyo Kabushiki Kaisha | Optically antisotropic carbonaceous pitch |
| US4590055A (en) * | 1982-08-24 | 1986-05-20 | Director-General Of The Agency Of Industrial Science And Technology | Pitch-based carbon fibers and pitch compositions and precursor fibers therefor |
| US4589974A (en) * | 1981-09-07 | 1986-05-20 | Toa Nenryo Kogyo Kabushiki Kaisha | Optically anisotropic carbonaceous pitch and process for producing the same |
| US5037697A (en) * | 1986-01-22 | 1991-08-06 | Nitto Boseki Co., Ltd. | Carbon fiber and process for producing the same |
| US5356574A (en) * | 1992-09-22 | 1994-10-18 | Petoca, Ltd. | Process for producing pitch based activated carbon fibers and carbon fibers |
| CN108587664A (en) * | 2018-03-29 | 2018-09-28 | 武汉科技大学 | A kind of thin mosaic texture mesophase pitch and preparation method thereof and its application in high-strength high-density graphite material |
| CN109112671A (en) * | 2018-06-15 | 2019-01-01 | 武汉科技大学 | A kind of preparation method of the regulatable Mesophase Pitch-based Carbon Fibers of microstructure and properties |
| CN112625722A (en) * | 2020-11-14 | 2021-04-09 | 北京化工大学 | Method for preparing spinnable asphalt by combining raw materials and application of spinnable asphalt in preparation of carbon fibers |
-
2022
- 2022-08-23 CN CN202211010301.3A patent/CN115369520B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4534850A (en) * | 1980-11-19 | 1985-08-13 | Toa Nenryo Kogyo Kabushiki Kaisha | Optically antisotropic carbonaceous pitch |
| US4589974A (en) * | 1981-09-07 | 1986-05-20 | Toa Nenryo Kogyo Kabushiki Kaisha | Optically anisotropic carbonaceous pitch and process for producing the same |
| US4590055A (en) * | 1982-08-24 | 1986-05-20 | Director-General Of The Agency Of Industrial Science And Technology | Pitch-based carbon fibers and pitch compositions and precursor fibers therefor |
| US5037697A (en) * | 1986-01-22 | 1991-08-06 | Nitto Boseki Co., Ltd. | Carbon fiber and process for producing the same |
| US5356574A (en) * | 1992-09-22 | 1994-10-18 | Petoca, Ltd. | Process for producing pitch based activated carbon fibers and carbon fibers |
| CN108587664A (en) * | 2018-03-29 | 2018-09-28 | 武汉科技大学 | A kind of thin mosaic texture mesophase pitch and preparation method thereof and its application in high-strength high-density graphite material |
| CN109112671A (en) * | 2018-06-15 | 2019-01-01 | 武汉科技大学 | A kind of preparation method of the regulatable Mesophase Pitch-based Carbon Fibers of microstructure and properties |
| CN112625722A (en) * | 2020-11-14 | 2021-04-09 | 北京化工大学 | Method for preparing spinnable asphalt by combining raw materials and application of spinnable asphalt in preparation of carbon fibers |
Non-Patent Citations (1)
| Title |
|---|
| PREPARATION OF CARBON FIBER FROM ISOTROPIC PITCH CONTAINING MESOPHASE SPHERES;Y.KORAI等;Pergamon;第35卷(第12期);第1733-1737页 * |
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