CN115232246A - Polymer for polyacrylonitrile-based large-tow carbon fiber, preparation method and polyacrylonitrile-based large-tow carbon fiber - Google Patents
Polymer for polyacrylonitrile-based large-tow carbon fiber, preparation method and polyacrylonitrile-based large-tow carbon fiber Download PDFInfo
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- CN115232246A CN115232246A CN202110434140.XA CN202110434140A CN115232246A CN 115232246 A CN115232246 A CN 115232246A CN 202110434140 A CN202110434140 A CN 202110434140A CN 115232246 A CN115232246 A CN 115232246A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/42—Nitriles
- C08F220/44—Acrylonitrile
- C08F220/46—Acrylonitrile with carboxylic acids, sulfonic acids or salts thereof
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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
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F6/38—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising unsaturated nitriles as the major constituent
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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
- D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
- D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F9/22—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles
Abstract
The invention discloses a polymer for polyacrylonitrile-based large-tow carbon fibers, a preparation method of the polymer and the polyacrylonitrile-based large-tow carbon fibers. The polymer comprises an acrylonitrile structural unit, a second comonomer structural unit, a third comonomer structural unit and a fourth comonomer structural unit, wherein the acrylonitrile structural unit is derived from acrylonitrile, the second comonomer structural unit is derived from a second comonomer, the third comonomer structural unit is derived from a third comonomer, and the fourth comonomer structural unit is derived from a fourth comonomer. The invention introduces the fourth comonomer, utilizes the volume effect of the side group to reduce the cohesive energy of the molecular weight of the polyacrylonitrile copolymer, improves the spinnability, and the resin potentially leaves a molecular oxygen permeation channel in the presentation process, thereby promoting the preoxidation double diffusion reaction to carry out. The strength and the modulus of the large-tow carbon fiber obtained by the method are improved.
Description
Technical Field
The invention relates to the technical field of preparation of polyacrylonitrile-based large-tow carbon fibers, in particular to a polymer for the polyacrylonitrile-based large-tow carbon fibers, a preparation method and the polyacrylonitrile-based large-tow carbon fibers.
Background
The polyacrylonitrile-based carbon fiber is a high-performance fiber material prepared from polyacrylonitrile protofilament serving as a raw material through processes of pre-oxidation, carbonization and the like, and is one of the high-performance fiber materials which are developed fastest and applied most widely at present. The large-tow carbon fiber belongs to general-purpose carbon fiber, and is widely applied to the fields of leisure and sports goods, infrastructures, industrial application and the like.
In the preparation process, binary or ternary copolymerization is mostly adopted for preparing the conventional carbon fiber spinning solution, because the homopolymerized acrylonitrile polymer has higher rigidity, the spinnability of the solution is poorer, and the phenomenon of over concentration can also occur in the later preoxidation and carbonization processes, so that the fibers are easy to break in the oxidation, carbonization and drafting processes, and the mechanical property of the carbon fibers is reduced. Thus, the second and third comonomers are generally used to improve spinnability of the polyacrylonitrile stock solution and to moderate the exothermic effects of the oxidative carbonization process. However, compared with small-tow carbon fibers, the preparation technology of a plurality of links such as preparation, polymerization, pre-oxidation, carbonization and the like of large-tow carbon fiber precursors is more difficult, and the main problems of production are mostly concentrated in the following steps: the heat is released more and concentrated in the oxidation process, and is not easy to be dispersed, so that the fibers are broken; unstable uniformity of filament bundles, etc. In order to solve the problems of more preoxidation heat release, concentration and difficult dispersion in large tows, the invention introduces a fourth comonomer in the copolymerization process.
Disclosure of Invention
In order to solve the problems of more heat release, concentration and difficult dispersion of large-tow carbon fibers in the oxidation process, the invention provides a polymer for polyacrylonitrile-based large-tow carbon fibers, a preparation method and preparation methods of the polyacrylonitrile-based large-tow carbon fibers and the polyacrylonitrile-based large-tow carbon fibers.
One of the purposes of the present invention is to provide a polymer for polyacrylonitrile-based macrotow carbon fibers, which comprises an acrylonitrile structural unit, a second comonomer structural unit, a third comonomer structural unit and a fourth comonomer structural unit, wherein the acrylonitrile structural unit is derived from acrylonitrile, the second comonomer structural unit is derived from a second comonomer, the third comonomer structural unit is derived from a third comonomer, and the fourth comonomer structural unit is derived from a fourth comonomer, wherein the second comonomer is at least one of itaconic acid, sodium itaconate or ammonium itaconate, the third comonomer is at least one of methyl acrylate, acrylic acid or methyl methacrylate, and the fourth comonomer is at least one of n-butyl methacrylate, sec-butyl methacrylate or isobutyl methacrylate.
In the polymer of the present invention, further, the polymer may further comprise, based on 100wt% of the total weight of the polymer,
the content of acrylonitrile structural units is 91 to 98.5wt%, preferably 92 to 97wt%;
the content of the second comonomer structural unit is 0.5 to 2.5wt%, preferably 1 to 2wt%;
the content of the third comonomer structural unit is 0.5 to 5.5wt%, preferably 1 to 4wt%;
the content of the fourth comonomer structural unit is 0.5 to 5.5wt%, preferably 1 to 4wt%.
The polymer can be used for preparing large-tow carbon fibers with the number of fibers per tow being 48K and above, and is preferably 48K.
The invention also provides a preparation method of the polyacrylonitrile-based macrotow polymer for carbon fibers, which comprises the following steps: the components comprising acrylonitrile, a second comonomer, a third comonomer, a fourth comonomer, an initiator and a chain transfer agent are subjected to solution polymerization in a solvent.
In the preparation method of the polymer, the second comonomer is at least one of itaconic acid, sodium itaconate or itaconic amine, the third comonomer is at least one of methyl acrylate, acrylic acid or methyl methacrylate, and the fourth comonomer is at least one of n-butyl methacrylate, sec-butyl methacrylate or isobutyl methacrylate.
In the preparation method of the polymer, the mass ratio of the acrylonitrile to the second comonomer to the third comonomer to the fourth comonomer is preferably (91-98.5) to (0.5-2.5) to (0.5-5.5) and more preferably (92-97) to (1-2) to (1-4) based on 100 parts by mass of the total mass of the acrylonitrile to the second comonomer to the third comonomer.
In the preparation method of the polymer, the initiator is preferably at least one of azobisisobutyronitrile, azobisisoheptonitrile and azobisisobutylamidine hydrochloride.
The initiator is 0.1-0.25 wt%, preferably 0.12-0.23 wt% of the amount of acrylonitrile.
In the method for preparing the polymer, the chain transfer agent is preferably at least one of isopropanol, mercaptoethanol, n-dodecyl mercaptan and tert-butyl mercaptan.
The chain transfer agent is 0.1-8 wt%, preferably 0.5-6 wt% of the amount of acrylonitrile.
In the preparation method of the polymer, the solvent is sodium thiocyanate aqueous solution, wherein the content of sodium thiocyanate is 35-50 wt%.
In the preparation method of the polymer, the temperature of solution polymerization is 65-80 ℃, and preferably 66-79 ℃; the polymerization time is from 1 to 3 hours, preferably from 1 to 2 hours.
The invention also aims to provide a preparation method of the polyacrylonitrile-based large-tow carbon fiber, which comprises a spinning solution preparation step, a spinning step and an oxidation carbonization step, wherein the spinning solution contains the polymer or the polymer obtained by the preparation method.
Preferably, the preparation method of the polyacrylonitrile-based large tow carbon fiber can comprise the following steps:
the preparation method of the spinning solution comprises the following steps: preparing a spinning solution from raw materials comprising acrylonitrile, a second comonomer, a third comonomer, a fourth comonomer, an initiator, a chain transfer agent and a solvent by a solution polymerization method;
spinning: spinning the spinning solution by a wet spinning process,
it may preferably be: extruding, solidifying and molding the spinning stock solution, and then carrying out hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain polyacrylonitrile-based large-tow carbon fiber precursor;
and (3) an oxidation carbonization step: and (3) pre-oxidizing, carbonizing, sizing and drying the polyacrylonitrile-based large tow carbon fiber precursor to obtain the polyacrylonitrile-based large tow carbon fiber.
In the above spinning dope preparation step, preferably,
the solution polymerization is to add acrylonitrile, a second comonomer, a third comonomer, a fourth comonomer, an initiator, a chain transfer agent and a solvent into a polymerization kettle, react for 1-3 hours at 65-80 ℃, and then demonomerize and defoam the obtained product to prepare the spinning solution for the polyacrylonitrile-based carbon fiber large tows.
In the solution polymerization process, the mass ratio of the acrylonitrile to the second comonomer to the third comonomer to the fourth comonomer is (91-98.5) to (0.5-2.5) to (0.5-5.5), preferably (92-97) to (1-2) to (1-4).
In the above spinning steps, there is no particular limitation on the processes of spinning dope extrusion, coagulation forming, hot water drawing, washing, oiling, drying, steam drawing and shaping, and the steps and process conditions in the existing production process of large tow carbon fiber can be adopted.
In the oxidation carbonization step, the processes of pre-oxidation, carbonization, sizing and drying are not particularly limited, and the steps and process conditions in the existing large-tow carbon fiber production process can be adopted.
The number of fibers per bundle of the large tow carbon fiber obtained by the above method for producing a large tow carbon fiber is preferably 48K.
The fourth purpose of the invention is to provide the polyacrylonitrile-based large tow carbon fiber obtained by the preparation method of the polyacrylonitrile-based large tow carbon fiber.
The invention has the following advantages:
the fourth comonomer introduced by the invention has larger side groups, the cohesive energy of the molecular weight of the polyacrylonitrile copolymer can be reduced by the volume effect of the side groups, the spinnability is improved, molecular oxygen permeation channels are potentially left in the resin presenting process, the preoxidation double diffusion reaction is promoted to be carried out, the skin-core structure is lightened or eliminated, the distribution gradient of inner and outer oxygen is improved, and the homogeneous preoxidized yarn is easier to prepare. The strength and the modulus of the large-tow carbon fiber obtained by the invention are improved, and the polymerization, spinning and oxidation carbonization equipment and most process parameters in the existing production process of the large-tow carbon fiber are not changed, so that the method is easy for industrial popularization.
The present invention will be further illustrated by the following examples, but is not limited to these examples.
Detailed Description
While the present invention will be described in detail with reference to the following examples, it should be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the present invention.
The raw materials used in the examples and comparative examples are disclosed in the prior art if not particularly limited, and may be, for example, directly purchased or prepared according to the preparation methods disclosed in the prior art.
[ example 1 ] A method for producing a polycarbonate
Adding 94.0wt% of acrylonitrile, 1.5wt% of itaconic acid, 1.5wt% of methyl acrylate, 3.0wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to prepare the stock solution for the polyacrylonitrile-based carbon fiber large tow.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 4.0GPa and the elastic modulus of 241GPa.
[ example 2 ]
Adding 92.5wt% of acrylonitrile, 1.5wt% of itaconic acid, 0.5wt% of methyl acrylate, 5.5wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile), and 80wt% of sodium thiocyanate aqueous solution (the content of sodium thiocyanate is 48.5wt% of sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to obtain the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 3.5GPa and the elastic modulus of 223GPa.
[ example 3 ]
Adding 92.5wt% of acrylonitrile, 1.5wt% of itaconic acid, 5.5wt% of methyl acrylate, 0.5wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azobisisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to obtain the stock solution for the polyacrylonitrile-based carbon fiber large tow.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 3.1GPa and the elastic modulus of 209GPa.
[ example 4 ] A method for producing a polycarbonate
Adding 97.5wt% of acrylonitrile, 1.5wt% of itaconic acid, 0.5wt% of methyl acrylate, 0.5wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to obtain the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large tow carbon fiber with the fiber strength of 2.8GPa and the elastic modulus of 199GPa.
[ example 5 ]
Adding 92.5wt% of acrylonitrile, 1.5wt% of itaconic acid, 3.0wt% of methyl acrylate, 3.0wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile), and 80wt% of sodium thiocyanate aqueous solution (the content of sodium thiocyanate is 48.5wt% of sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to obtain the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 4.2GPa and the elastic modulus of 241GPa.
[ example 6 ] A method for producing a polycarbonate
Adding 94.0wt% of acrylonitrile, 1.5wt% of itaconic acid, 1.5wt% of methyl acrylate, 3.0wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 3 hours at 65 ℃, and performing demonomerization and defoaming on the obtained product to obtain the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 3.8GPa and the elastic modulus of 237GPa.
[ example 7 ] A method for producing a polycarbonate
Adding 94.0wt% of acrylonitrile, 1.5wt% of itaconic acid, 1.5wt% of methyl acrylate, 3.0wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 1 hour at 80 ℃, and performing demonomerization and defoaming on the obtained product to prepare the stock solution for the polyacrylonitrile-based carbon fiber large tow.
Then spinning the solution by using a wet spinning process, extruding a spinning stock solution into a coagulating bath through a spinning nozzle, and carrying out hot water drawing, washing, oiling, drying, steam drawing and shaping to obtain 48K polyacrylonitrile-based large tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 3.7GPa and the elastic modulus of 238GPa.
[ example 8 ]
Adding 94.0wt% of acrylonitrile, 1.5wt% of itaconic acid, 1.5wt% of methyl acrylate, 3.0wt% of n-butyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile), and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 3 hours at 65 ℃, and performing demonomerization and defoaming on the obtained product to prepare the stock solution for the polyacrylonitrile-based carbon fiber large tow.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large tow carbon fiber with the fiber strength of 3.6GPa and the elastic modulus of 235GPa.
[ example 9 ] A method for producing a polycarbonate
Adding 93.8wt% of acrylonitrile, 3.0wt% of itaconic acid, 3.0wt% of methyl acrylate, 0.2wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile), and 80wt% of sodium thiocyanate aqueous solution (the content of sodium thiocyanate is 48.5wt% of sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 3 hours at 65 ℃, and performing demonomerization and defoaming on the obtained product to obtain the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Then spinning the solution by using a wet spinning process, extruding a spinning stock solution into a coagulating bath through a spinning nozzle, and carrying out hot water drawing, washing, oiling, drying, steam drawing and shaping to obtain 48K polyacrylonitrile-based large tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 2.5GPa and the elastic modulus of 182GPa.
Comparative example 1
Adding 94.0wt% of acrylonitrile, 3.0wt% of itaconic acid, 3.0wt% of methyl acrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile), and 80wt% of sodium thiocyanate aqueous solution (the content of sodium thiocyanate is 48.5wt% of sodium thiocyanate aqueous solution) of the total mass into a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to prepare the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 2.3GPa and the elastic modulus of 179GPa.
Comparative example 2
Adding 94.0wt% of acrylonitrile, 2.25wt% of itaconic acid, 3.75wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile), and 80wt% of sodium thiocyanate aqueous solution (the content of sodium thiocyanate is 48.5wt% of sodium thiocyanate aqueous solution) in a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to prepare the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Spinning the solution by using a wet spinning process, extruding a spinning solution into a coagulating bath through a spinning nozzle, and performing hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain 48K polyacrylonitrile-based large-tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 2.9GPa and the elastic modulus of 221GPa.
[ COMPARATIVE EXAMPLE 3 ]
Adding 94.0wt% of acrylonitrile, 2.25wt% of methyl acrylate, 3.75wt% of isobutyl methacrylate, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) in a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to prepare the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Then spinning the solution by using a wet spinning process, extruding a spinning stock solution into a coagulating bath through a spinning nozzle, and carrying out hot water drawing, washing, oiling, drying, steam drawing and shaping to obtain 48K polyacrylonitrile-based large tow carbon fiber precursor;
finally, the pre-oxidation and carbonization processes of the protofilament are not smooth, and the continuous filament winding is difficult.
Comparative example 4
Adding 94.0wt% of acrylonitrile, 1.5wt% of itaconic acid, 1.5wt% of methyl acrylate, 3.0wt% of acrylamide, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the sodium thiocyanate content is 48.5wt% of the sodium thiocyanate aqueous solution) to a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to prepare the stock solution for the polyacrylonitrile-based carbon fiber large tow.
Then spinning the solution by using a wet spinning process, extruding a spinning stock solution into a coagulating bath through a spinning nozzle, and carrying out hot water drawing, washing, oiling, drying, steam drawing and shaping to obtain 48K polyacrylonitrile-based large tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 2.7GPa and the elastic modulus of 211GPa.
[ COMPARATIVE EXAMPLE 5 ]
Adding 94.0wt% of acrylonitrile, 1.5wt% of itaconic acid, 1.5wt% of methyl acrylate, 3.0wt% of methacrylic acid, 4.0wt% of isopropanol (mass of acrylonitrile), 0.2wt% of azodiisobutyronitrile (mass of acrylonitrile) and 80wt% of sodium thiocyanate aqueous solution (the content of sodium thiocyanate is 48.5wt% of sodium thiocyanate aqueous solution) into a polymerization kettle by a metering pump, reacting for 1.5h at 78 ℃, and performing demonomerization and defoaming on the obtained product to obtain the stock solution for the polyacrylonitrile-based carbon fiber large tows.
Then spinning the solution by using a wet spinning process, extruding a spinning stock solution into a coagulating bath through a spinning nozzle, and carrying out hot water drawing, washing, oiling, drying, steam drawing and shaping to obtain 48K polyacrylonitrile-based large tow carbon fiber precursor;
and finally, pre-oxidizing, carbonizing, sizing and drying the precursor to obtain the 48K polyacrylonitrile-based large-tow carbon fiber with the fiber strength of 2.9GPa and the elastic modulus of 218GPa.
Claims (10)
1. The polymer for the polyacrylonitrile-based macrotow carbon fibers comprises an acrylonitrile structural unit, a second comonomer structural unit, a third comonomer structural unit and a fourth comonomer structural unit, wherein the second comonomer structural unit is derived from a second comonomer, the third comonomer structural unit is derived from a third comonomer, the fourth comonomer structural unit is derived from a fourth comonomer, the second comonomer is at least one of itaconic acid, sodium itaconate or ammonium itaconate, the third comonomer is at least one of methyl acrylate, acrylic acid or methyl methacrylate, and the fourth comonomer is at least one of n-butyl methacrylate, sec-butyl methacrylate or isobutyl methacrylate.
2. The polymer for polyacrylonitrile-based macrotow carbon fibers according to claim 1, characterized in that:
the content of acrylonitrile structural units is 91 to 98.5wt%, preferably 92 to 97wt%;
the content of the second comonomer structural unit is 0.5 to 2.5wt%, preferably 1 to 2wt%;
the content of the third comonomer structural unit is 0.5 to 5.5wt%, preferably 1 to 4wt%;
the content of the fourth comonomer structural unit is 0.5 to 5.5wt%, preferably 1 to 4wt%.
3. A method of preparing the polymer of claim 1 or 2, comprising:
the components comprising acrylonitrile, a second comonomer, a third comonomer, a fourth comonomer, an initiator and a chain transfer agent are subjected to solution polymerization in a solvent.
4. A method of producing a polymer according to claim 3, characterized in that:
the mass ratio of the acrylonitrile to the second comonomer to the third comonomer to the fourth comonomer is (91-98.5) to (0.5-2.5) to (0.5-5.5), preferably (92-97) to (1-2) to (1-4).
5. A method of preparing a polymer according to claim 3, characterized in that:
the initiator is at least one of azodiisobutyronitrile, azodiisoheptonitrile and azodiisobutyl amidine hydrochloride; and/or the presence of a gas in the gas,
the chain transfer agent is at least one of isopropanol, mercaptoethanol, n-dodecyl mercaptan and tert-butyl mercaptan; and/or the presence of a gas in the gas,
the solvent is sodium thiocyanate aqueous solution, wherein the content of the sodium thiocyanate is 35-50 wt%.
6. A method of preparing a polymer according to claim 3, characterized in that:
the initiator is 0.1 to 0.25wt percent of the using amount of the acrylonitrile, and preferably 0.12 to 0.23wt percent; and/or the presence of a gas in the gas,
the chain transfer agent is 0.1-8 wt%, preferably 0.5-6 wt% of the amount of acrylonitrile.
7. A method of preparing a polymer according to claim 3, characterized in that:
the temperature of solution polymerization is 65-80 ℃, and preferably 66-79 ℃; the polymerization time is from 1 to 3 hours, preferably from 1 to 2 hours.
8. A process for producing polyacrylonitrile-based macrotow carbon fibers, comprising a spinning dope preparation step, a spinning step and an oxidative carbonization step, wherein the spinning dope comprises the polymer as described in any one of claims 1 to 2 or the polymer obtained by the production process as described in any one of claims 3 to 7.
9. The method for preparing polyacrylonitrile-based macrotow carbon fibers according to claim 8, characterized by comprising the steps of:
the preparation method of the spinning solution comprises the following steps: preparing a spinning solution from acrylonitrile, a second comonomer, a third comonomer, a fourth comonomer, an initiator, a chain transfer agent and a solvent by a solution polymerization method;
spinning: extruding, solidifying and molding the spinning stock solution, and then carrying out hot water drafting, washing, oiling, drying, steam drafting and shaping to obtain polyacrylonitrile-based large-tow carbon fiber precursor;
oxidation and carbonization: and pre-oxidizing, carbonizing, sizing and drying the polyacrylonitrile-based large-tow carbon fiber precursor to obtain the polyacrylonitrile-based large-tow carbon fiber.
10. The polyacrylonitrile-based large-tow carbon fiber obtained by the production method according to claim 8 or 9.
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| JPH10130963A (en) * | 1996-09-04 | 1998-05-19 | Toray Ind Inc | Carbon fiber, precursor for carbon fiber and production thereof |
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| US20210054539A1 (en) * | 2019-08-20 | 2021-02-25 | Montefibre Mae Technologies S.R.L. | Optimized process for the preparation of a spinning solution for the production of acrylic fibers precursors of carbon fibers and the relative carbon fibers |
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| JPH10130963A (en) * | 1996-09-04 | 1998-05-19 | Toray Ind Inc | Carbon fiber, precursor for carbon fiber and production thereof |
| CN103184588A (en) * | 2013-04-15 | 2013-07-03 | 西安康本材料有限公司 | Manufacturing method of 12K quaternary polyacrylonitrile-based carbon fiber |
| WO2018208075A1 (en) * | 2017-05-10 | 2018-11-15 | 재단법인 한국탄소융합기술원 | Quad-polymer precursor for producing carbon fiber, method for producing same and method for using same |
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