CN111662407A - Efficient polymerization preparation method of polyacrylonitrile polymer for carbon fiber - Google Patents

Efficient polymerization preparation method of polyacrylonitrile polymer for carbon fiber Download PDF

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CN111662407A
CN111662407A CN202010764262.0A CN202010764262A CN111662407A CN 111662407 A CN111662407 A CN 111662407A CN 202010764262 A CN202010764262 A CN 202010764262A CN 111662407 A CN111662407 A CN 111662407A
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reaction
polymerization reaction
carbon fiber
polymerization
polyacrylonitrile
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CN111662407B (en
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敖琪
庄晗
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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
    • 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
    • C08F2/00—Processes of polymerisation
    • 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
    • C08F2/00—Processes of polymerisation
    • C08F2/04—Polymerisation in solution
    • C08F2/06—Organic solvent
    • 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

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Inorganic Fibers (AREA)

Abstract

The invention discloses a high-efficiency polymerization preparation method of polyacrylonitrile polymer for carbon fibers, wherein a polymerization reaction composition comprises a binary copolymerization system or a multi-copolymerization system containing acrylonitrile, the polymerization reaction conditions are that the reaction temperature is 78-150 ℃, the reaction pressure is 1.5-50 atmospheric pressures, the reaction time is 10-120 min, residual monomers and bubbles are removed to obtain polyacrylonitrile spinning solution, the obtained polymer is spun, and the obtained carbon fiber precursor is subjected to preoxidation carbonization to obtain polyacrylonitrile-based carbon fibers. The temperature of the polymerization reaction is increased in the acrylonitrile solvent polymerization reaction, and the time of the polymerization reaction is greatly shortened on the premise of ensuring the high performance of the polymer by the acrylonitrile polymerization reaction, so that the speed of the polymerization reaction is greatly increased, and the production efficiency is greatly improved.

Description

Efficient polymerization preparation method of polyacrylonitrile polymer for carbon fiber
Technical Field
The invention relates to a preparation method of a polyacrylonitrile-based protofilament polymer, in particular to a solution high-efficiency polymerization method of polyacrylonitrile, and a preparation method of carbon fiber protofilaments and carbon fibers prepared from the polymer.
Background
The carbon fiber is a special high-performance fiber with high specific strength and high specific modulus, wherein the carbon content of the special high-performance fiber is more than 90%. The composite material has a series of comprehensive properties of low density, high temperature resistance, friction resistance, electric conduction, heat conduction, corrosion resistance, radiation resistance, good damping and the like. Has been widely used in various fields of military and civilian such as: the manufacture of aerospace, aircraft, and sports equipment.
The polyacrylonitrile-based carbon fiber has excellent comprehensive performance, is a hotspot of research and industrialization in the field of carbon fiber, and is also applied to reinforcement in the field of carbon fiber composite materials. The application field is wide, and the market demand of the carbon fiber is improved unprecedentedly. Therefore, on the premise of ensuring the high performance of the polyacrylonitrile-based carbon fiber, the high-efficiency production of the carbon fiber is very necessary. The preparation process of polyacrylonitrile-based precursor and carbon fiber is basically determined, and is difficult to improve, shorten the preparation time and carry out high-efficiency production, so that starting from the synthesis of polyacrylonitrile, in order to obtain excellent polyacrylonitrile precursor and polyacrylonitrile-based carbon fiber, spinning solution with excellent performance (moderate molecular weight, narrow molecular weight distribution, good spinnability and the like) is required to be selected, and on the premise of ensuring the excellent performance of the spinning solution, the polyacrylonitrile needs to be subjected to high-efficiency high-performance polymerization. Chinese patent CN101280041A discloses a polymerization reaction composition containing acrylonitrile and alkaline compound, carbon fiber precursor and carbon fiber prepared from the polymerization reaction composition, and preparation methods of precursor and carbon fiber, wherein the polymerization reaction conditions are as follows: the azodiisobutyronitrile is used as an initiator for solution copolymerization, the reaction temperature is 50-70 ℃, and the reaction time is 20-28 hours.
Chinese patent CN102102235B discloses a polyacrylonitrile-based high-performance carbon fiber spinning solution containing a vinyl silane structural unit and a preparation method thereof, wherein the polymerization reaction conditions are as follows: the azodiisobutyronitrile is used as an initiator for solution copolymerization, the reaction temperature is 50-70 ℃, and the reaction time is 12-30 hours.
Chinese patent CN103422187A discloses a preparation method of a low-viscosity and high-performance carbon fiber spinning solution. The polymerization reaction conditions are as follows: the azodiisobutyronitrile is used as an initiator for solution copolymerization, the reaction temperature is 50-70 ℃, and the reaction time is 20-40 hours.
For many years, researchers have been concerned with modifying polyacrylonitrile resins by attempting to select different comonomers or by attempting to modify different polymerization methods, and it is desired to obtain spinning dope with excellent properties, but we have found that the polymerization reaction time is mostly 10 hours or more, and in the case where the demand for carbon fibers is so great, it is necessary to improve the polymerization reaction efficiency.
Disclosure of Invention
The invention aims to provide a high-efficiency polymerization preparation method of polyacrylonitrile polymer for carbon fibers at high temperature, which can greatly accelerate the polymerization reaction, greatly reduce the reaction time, realize high-efficiency polymerization, and simultaneously keep the advantages of narrow molecular weight distribution and regular molecular arrangement sequence of the copolymer.
A high-efficiency polymerization preparation method of polyacrylonitrile polymer for carbon fibers comprises the steps of using a polymerization reaction composition to comprise a binary copolymerization system or a multi-copolymerization system containing acrylonitrile, wherein the reaction conditions are that the reaction temperature is 78-150 ℃, the reaction pressure is 1.5-50 atmospheric pressures, the reaction time is 10-120 min, removing residual monomers and bubbles to obtain polyacrylonitrile spinning solution, spinning the obtained polymer, and pre-oxidizing and carbonizing the obtained carbon fiber precursors to obtain the polyacrylonitrile-based carbon fibers.
The binary copolymerization system or the ternary multiple copolymerization system comprises 90 to 99 weight percent of acrylonitrile, 0.2 to 7 weight percent of second monomer, 0.1 to 5 weight percent of third monomer and 0.3 to 2.0 weight percent of initiator azobisisobutyronitrile.
The interpolymer system is a binary copolymerization system containing acrylonitrile and a second monomer or a multi-component (e.g., ternary) copolymerization system consisting of acrylonitrile, the second monomer and other monomers (e.g., a third monomer). Wherein the second monomer is acid selected from itaconic acid, acrylic acid, methacrylic acid, maleic anhydride, etc. or their mixture, and the third monomer is lipid selected from alkyl acrylate, alkyl methacrylate, vinyl acetate, vinyl propionate, styrene, vinyl chloride, ethylene dichloride or their mixture. Most preferably, the binary interpolymer is a copolymer of acrylonitrile and itaconic acid and the ternary interpolymer is a copolymer of acrylonitrile, itaconic acid and methyl acrylate.
The solvent for the polymerization reaction of the present invention is dimethyl sulfoxide (DMSO), Dimethylformamide (DMF) or Dimethylacetamide (DMAC), preferably dimethyl sulfoxide (DMSO).
The initiator for the polymerization reaction of the present invention is an azo initiator such as azobisisobutyronitrile or azobisisoheptonitrile, preferably azobisisobutyronitrile.
The invention also relates to the conditions of the polymerization reaction, wherein the temperature of the polymerization reaction is 78-150 ℃, and in order to ensure homogeneous high-performance polymerization of the polymerization reaction, the pressure of the polymerization reaction is increased along with the increase of the temperature, and the pressure of the polymerization reaction is controlled to be 1.5-50 atmospheric pressures.
Compared with the prior art, the invention has the following technical effects:
1. the temperature of the polymerization reaction is increased in the acrylonitrile solvent polymerization reaction, and compared with the conventional acrylonitrile solution polymerization reaction, the acrylonitrile polymerization reaction greatly shortens the polymerization reaction time on the premise of ensuring the high performance of a polymer, thereby greatly improving the polymerization reaction rate.
2. The invention controls the polymerization reaction temperature, not only can improve the polymerization reaction rate, but also can adjust the molecular weight of the polymer by controlling the temperature and the pressure.
3. The polymer prepared by the method has the molecular weight intrinsic viscosity of 0.250-0.254, the weight average molecular weight of 17.6-26.1 ten thousand and the molecular weight distribution index of 1.65-3.03; has the characteristics of narrow molecular weight distribution and orderly molecular arrangement sequence. The polyacrylonitrile protonema density is preferably 1.18-1.21g/cm through the test of a sample3. The strength of the carbonized carbon fiber is 4.53-5.63 GPa.
Detailed Description
Comparative example:
azo-bis-isobutyronitrile (AIBN) is used as initiator and bisMethyl Sulfoxide (DMSO) is used as a solvent to carry out acrylonitrile solution copolymerization. Putting acrylonitrile, itaconic acid and methyl acrylate into a polymerization reaction kettle according to the weight ratio of 97.5%, 1.3% and 1.8% of azodiisobutyronitrile according to the weight ratio of 1.3%, adding a solvent DMSO, controlling the mass concentration of the monomer in the solvent to be 20%, and reacting at the temperature of 65 ℃ for 24 hours. And removing residual monomers and bubbles in vacuum to obtain the spinning solution. The weight average molecular weight of the copolymer was 22.4 ten thousand, and the molecular weight distribution index was 2.98. Spinning and pre-oxidation carbonization are carried out under standard conditions to obtain PAN-based protofilament with the bulk density of 1.195g/cm3The carbon fiber strength was 4.91 GPa.
Example 1:
the polymerization formulation of the comparative example was charged into a reaction vessel and the reaction was carried out for 120 minutes while controlling the reaction temperature at 78 ℃ and the reaction pressure at 1.5 atm. And removing residual monomers and bubbles in vacuum to obtain the spinning solution. The copolymer had a weight average molecular weight of 20.1 ten thousand and a molecular weight distribution index of 2.28. Spinning and pre-oxidation carbonization are carried out under standard conditions to obtain PAN-based protofilament with the bulk density of 1.185g/cm3The carbon fiber strength was 5.57 GPa.
Example 2:
the polymerization formulation of the comparative example was charged into a reaction vessel, and the reaction temperature was controlled at 85 ℃ and the reaction pressure at 3.2 atm, and the reaction was carried out for 80 minutes. And removing residual monomers and bubbles in vacuum to obtain the spinning solution. The copolymer had a weight average molecular weight of 21.4 ten thousand and a molecular weight distribution index of 2.58. Spinning and pre-oxidation carbonization are carried out under standard conditions to obtain PAN-based protofilament with the bulk density of 1.192g/cm3The strength of the carbon fiber was 5.08 GPa.
Example 3:
feeding the materials into a reaction kettle according to the polymerization formula of the comparative example, controlling the reaction temperature to be 90 ℃ and the reaction pressure to be 1.5 atmospheric pressure, reacting for 60 minutes, and removing residual monomers and bubbles in vacuum to obtain the spinning solution. The weight average molecular weight of the copolymer was 20.6 ten thousand, and the molecular weight distribution index was 2.66. Spinning and pre-oxidation carbonization are carried out under standard conditions to obtain PAN-based protofilament with the bulk density of 1.192g/cm3The carbon fiber strength was 4.94 GPa.
Example 4:
the polymerization formulation of the comparative example was charged into a reaction vessel, and the reaction temperature was controlled at 95 ℃ and the reaction pressure was controlled at 5.1 atm, and the reaction was carried out for 30 minutes to prepare the resulting polymer solution. And removing residual monomers and bubbles in vacuum to obtain the spinning solution. The copolymer had a weight average molecular weight of 21.8 ten thousand and a molecular weight distribution index of 2.78. Spinning and pre-oxidation carbonization are carried out under standard conditions to obtain PAN-based protofilament with the bulk density of 1.190g/cm3The carbon fiber strength was 4.76 GPa.
Example 5:
the polymerization formulation of the comparative example was charged into a reaction vessel, and the reaction temperature was controlled at 150 ℃ and the reaction pressure was controlled at 30 atm, and the reaction was carried out for 10 minutes to prepare the resulting polymer solution. And removing residual monomers and bubbles in vacuum to obtain the spinning solution. The weight average molecular weight of the copolymer was 22.3 ten thousand, and the molecular weight distribution index was 2.90. Spinning and pre-oxidation carbonization are carried out under standard conditions to obtain PAN-based protofilament with the bulk density of 1.194g/cm3The carbon fiber strength was 4.49 GPa.
Compared with the comparative examples in 5 embodiments, the invention can greatly improve the speed of the polymerization reaction under the conditions that the reaction temperature is 78-150 ℃ and the atmospheric pressure is 1.5-50.

Claims (3)

1. A high-efficiency polymerization preparation method of polyacrylonitrile polymer for carbon fibers is disclosed, wherein a composition of polymerization reaction comprises a binary copolymerization system or a multiple copolymerization system containing acrylonitrile, and the method is characterized in that: the conditions of the polymerization reaction are as follows: the reaction temperature is 78-150 ℃, the reaction pressure is 1.5-50 atmospheric pressures, the reaction time is 10min-120min, residual monomers and bubbles are removed to obtain polyacrylonitrile spinning solution, the obtained polymer is spun, and the obtained carbon fiber precursor is preoxidized and carbonized to obtain the polyacrylonitrile-based carbon fiber.
2. The method for preparing polyacrylonitrile polymer for carbon fiber by high efficiency polymerization according to claim 1, wherein: the solvent for the polymerization reaction is dimethyl sulfoxide, dimethyl formamide or dimethyl acetamide.
3. The method for preparing polyacrylonitrile polymer for carbon fiber by high efficiency polymerization according to claim 1, wherein: the initiator for the polymerization reaction is azo initiator such as azobisisobutyronitrile or azobisisoheptonitrile.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3499073A (en) * 1967-06-05 1970-03-03 Shih Ming Sun Melt spinning of acrylonitrile polymers
CN102336857A (en) * 2011-06-29 2012-02-01 中国石油天然气股份有限公司 SAN (Styrene Acrylonitrile) resin with high nitrile content and narrow distribution and preparation method thereof
CN103193929A (en) * 2013-04-15 2013-07-10 西安康本材料有限公司 Binary copolymerized polyacrylonitrile-based carbon fiber spinning solution and preparation method thereof
CN103804605A (en) * 2012-11-08 2014-05-21 姜丹宁 Method for preparing acrylonitrile-polypropylene graft copolymer
WO2016151872A1 (en) * 2015-03-26 2016-09-29 東レ株式会社 Polyacrylonitrile-based polymer, carbon-fiber-precursor fibers, and process for producing carbon fibers
CN107956002A (en) * 2017-11-14 2018-04-24 盐城天顺机械科技有限公司 A kind of carbon fiber production method
CN110684149A (en) * 2018-07-06 2020-01-14 中国石油化工股份有限公司 Preparation method of narrow-distribution polyacrylonitrile-based carbon fiber spinning solution

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3499073A (en) * 1967-06-05 1970-03-03 Shih Ming Sun Melt spinning of acrylonitrile polymers
CN102336857A (en) * 2011-06-29 2012-02-01 中国石油天然气股份有限公司 SAN (Styrene Acrylonitrile) resin with high nitrile content and narrow distribution and preparation method thereof
CN103804605A (en) * 2012-11-08 2014-05-21 姜丹宁 Method for preparing acrylonitrile-polypropylene graft copolymer
CN103193929A (en) * 2013-04-15 2013-07-10 西安康本材料有限公司 Binary copolymerized polyacrylonitrile-based carbon fiber spinning solution and preparation method thereof
WO2016151872A1 (en) * 2015-03-26 2016-09-29 東レ株式会社 Polyacrylonitrile-based polymer, carbon-fiber-precursor fibers, and process for producing carbon fibers
CN107956002A (en) * 2017-11-14 2018-04-24 盐城天顺机械科技有限公司 A kind of carbon fiber production method
CN110684149A (en) * 2018-07-06 2020-01-14 中国石油化工股份有限公司 Preparation method of narrow-distribution polyacrylonitrile-based carbon fiber spinning solution

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
徐梁华等: "《聚丙烯腈基碳纤维》", 30 November 2018, 国防工业出版社 *

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