CN-121992520-A - Phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber, preparation method and application

CN121992520ACN 121992520 ACN121992520 ACN 121992520ACN-121992520-A

Abstract

The invention discloses a phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber, a preparation method and application thereof, the flame-retardant polyacrylonitrile fiber is prepared by copolymerizing acrylonitrile, a phosphorus-containing reactive monomer and a silicon-containing reactive monomer in a polar organic solvent through a free radical solution to prepare a copolymer, and then carrying out wet spinning, drafting and drying. According to the invention, the flame-retardant structure is introduced into the polyacrylonitrile molecular chain in a reactive copolymerization mode, so that the migration and precipitation risk of flame-retardant components can be reduced, and the flame-retardant composite material has the advantages of clear process path, suitability for wet spinning implementation and the like, and is suitable for the fields of flame-retardant textiles, flame-retardant filter materials and the like.

Inventors

XI ZHENHAO
ZHAO LING
LI CHENYANG
LI JINJIN
JIANG JIE
CHEN XINWEI

Assignees

华东理工大学

Dates

Publication Date: 20260508
Application Date: 20260408

Claims (13)

1. The preparation method of the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber is characterized by comprising the following steps of: S1, preparing a phosphorus-containing reactive monomer; S2, mixing acrylonitrile, a phosphorus-containing reactive monomer, a silicon-containing reactive monomer, a free radical initiator and an organic solvent, and carrying out free radical copolymerization in an inert atmosphere to obtain a phosphorus-silicon-containing reactive ternary copolymer polyacrylonitrile copolymer; S3, preparing spinning solution from the phosphorus-silicon-containing reactive ternary copolymer polyacrylonitrile copolymer obtained in the step S2, performing wet spinning or dry-jet wet spinning, entering a coagulating bath, and performing water washing, drafting and drying to obtain the flame-retardant polyacrylonitrile fiber.
2. The method for preparing the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber according to claim 1, wherein the phosphorus-containing reactive monomer is a reactive monomer containing a free radical polymerizable unsaturated group A and a phosphorus-containing functional group; The free radical polymerizable unsaturated group A is selected from one or more of vinyl, allyl, acrylate, methacrylate, acrylamide or methacrylamide; The phosphorus-containing functional group is selected from one or more of a phosphate group, a phosphonate amide group or a phosphonate amide group.
3. The method for preparing the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber according to claim 1, wherein the phosphorus-containing reactive monomer is an acid type, a partially neutralized salt or a fully neutralized salt, the cations of the partially neutralized salt or the fully neutralized salt are selected from one or more of hydrogen, ammonium, sodium, potassium or organic amine cations, and the organic amine cations comprise triethylamine, trimethylamine, monoethanolamine, diethanolamine or triethanolamine corresponding cations.
4. The method for preparing a phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber according to claim 1, wherein the silicon-containing reactive monomer is a reactive monomer containing a free radical polymerizable unsaturated group B and a silicon-containing group at the same time; the radical polymerizable unsaturated group B is selected from vinyl, allyl, (meth) acrylate or (meth) acrylamide groups; The silicon-containing group is selected from a hydrolyzable alkoxysilane group-Si (OR) 3 OR a monofunctional substituent containing a siloxane segment, wherein R is a C1-C4 alkyl group.
5. The method for preparing a phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber according to claim 1, wherein the silicon-containing reactive monomer is selected from one or more of the following: (1) (meth) acrylate monomers containing trialkoxysilane, namely 3- (trimethoxysilyl) propyl methacrylate, 3- (triethoxysilyl) propyl methacrylate, 3- (trimethoxysilyl) propyl acrylate, 3- (triethoxysilyl) propyl acrylate, 2- (trimethoxysilyl) ethyl methacrylate and 2- (triethoxysilyl) ethyl methacrylate; (2) Vinyl/allyl trialkoxysilane monomers including vinyl trimethoxysilane, vinyl triethoxysilane, allyl trimethoxysilane, allyl triethoxysilane; (3) Polymerizable monomers containing short-chain siloxane segments, oligomeric dimethylsiloxane monomers having terminal (meth) acrylate groups.
6. The method for preparing the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber as claimed in claim 1, wherein in the step S2, the phosphorus-containing reactive monomer is used in an amount of 2.0-18.0wt% based on the total mass of the monomers, the silicon-containing reactive monomer is used in an amount of 1.0-8.0wt% and the balance is acrylonitrile.
7. The method for preparing phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber according to claim 1, wherein in the step S2, the organic solvent is selected from one or more of dimethyl sulfoxide, N-dimethylformamide and N, N-dimethylacetamide, and the free radical initiator is selected from one or more of azobisisobutyronitrile, azobisisovaleronitrile and benzoyl peroxide.
8. The preparation method of the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber as claimed in claim 1, wherein in the step S2, the polymerization temperature of free radical copolymerization is 45-75 ℃, the polymerization time is 4-18 h, the total monomer concentration is 15-35 wt%, and the free radical initiator is 0.1-0.6 wt% of the total monomer mass.
9. The preparation method of the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber is characterized in that in the step S3, the solid content of a spinning solution is 18-28wt%, the coagulating bath is a water/organic solvent mixed system, the mass ratio of water/organic solvent in the coagulating bath is 40/60-80/20, the pH of the coagulating bath is 4.0-7.0, the temperature is 5-35 ℃, the water washing temperature is 15-60 ℃, the total draft multiple is 3-10 times, and the drying temperature is 60-140 ℃.
10. The method of claim 1, wherein in step S3, the spinning dope is prepared by one or more of the following steps: (1) Directly adding the dried phosphorus-silicon-containing reactive ternary copolymer polyacrylonitrile copolymer into DMF, DMSO or DMAc, heating, stirring and dissolving; (2) After the polymerization solvent is partially removed from the copolymerization reaction liquid obtained in the step S2, supplementing a target spinning solvent and adjusting the solid content; (3) Firstly preparing a phosphorus-silicon-containing reactive ternary copolymer polyacrylonitrile copolymer into a concentrated solution, and then diluting to the target solid content by adding a solvent.
11. The method for preparing the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber as claimed in claim 1, wherein the preparation method further comprises a metal ion treatment step after the step S3, wherein the flame-retardant polyacrylonitrile fiber is immersed in a treatment solution containing 0.005-0.20 mol/L metal salt for 0.5-30 min, the treatment temperature is 20-60 ℃, the pH of the treatment solution is 4.0-7.0, and then the treatment solution is washed and dried, wherein the metal salt is one or more selected from copper acetate, copper sulfate, ferric chloride, ferric nitrate and zinc acetate.
12. The phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber is characterized by being prepared by adopting the preparation method of the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber according to any one of claims 1-11; the mass fraction of phosphorus element in the flame-retardant polyacrylonitrile fiber is 0.20-2.00 wt%, and the mass fraction of silicon element is 0.10-1.50 wt%; The limiting oxygen index of the flame-retardant polyacrylonitrile fiber is 22.8% -30.1%.
13. The use of a phosphorus-silicon-containing reactive ternary polymerization flame retardant polyacrylonitrile fiber in the preparation of flame retardant textile and flame retardant filter materials according to claim 12.

Description

Phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber, preparation method and application Technical Field The invention relates to the technical field of flame retardant modification of polyacrylonitrile fibers, in particular to a phosphorus-silicon-containing reactive ternary polymerization flame retardant polyacrylonitrile fiber, a preparation method and application. Background Polyacrylonitrile (PAN) fiber has high strength, good chemical resistance and spinnability, and is widely applied to the fields of spinning, filtering and the like. Conventional PAN fibers have limited flame retardant performance, and are difficult to meet the application requirements of flame retardant working conditions. The existing additive type flame retardant scheme generally realizes flame retardance by adding a phosphorus-based or inorganic flame retardant into a spinning solution, but has the problems that firstly, the compatibility of the flame retardant and a PAN matrix is insufficient, the stability and the spinning continuity of the solution are affected, secondly, the flame retardant is easy to migrate and separate out in the use or washing process, the durability is poor, and thirdly, the mechanical property of the fiber is possibly weakened by the additive. The reactive flame-retardant modification can introduce a flame-retardant structure into a PAN molecular chain in a chemical bond form, and has the advantage of good flame-retardant durability. The phosphorus-containing structure is beneficial to promoting the formation of the condensed phase into carbon, and the silicon-containing structure is beneficial to improving the stability and compactness of the carbon layer. The phosphorus-containing reactive monomer and the silicon-containing reactive monomer are introduced into the PAN chain segment together, so that the synergistic improvement of the flame retardant property and the durability is expected to be realized on the premise of not obviously sacrificing the spinnability. However, less is disclosed in the prior art for the phosphorus-silicon reactive ternary polymerization scheme of PAN systems. Therefore, it is necessary to provide a technical scheme which can expand the monomer range, is preferable to have clear monomer, has clear process path and is suitable for spinning amplification. Disclosure of Invention The invention aims to provide a phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber, a preparation method and application thereof, wherein the flame-retardant polyacrylonitrile fiber is prepared by copolymerizing acrylonitrile, phosphorus-containing reactive monomers and silicon-containing reactive monomers through free radicals, and is prepared by spinning, the preparation process is simple, and the promotion of flame retardance, char formation capability and carbon layer stability is realized through the synergistic effect of a phosphorus-containing structure and a silicon-containing structure, so that the problems of insufficient compatibility, migration precipitation, poor washing fastness and larger influence on spinning stability and mechanical properties of the traditional additive flame-retardant system in the polyacrylonitrile fiber are solved, and the flame-retardant fiber has obvious positive practical significance. In order to achieve the aim of the invention, the technical scheme adopted by the invention is that the preparation method of the phosphorus-silicon-containing reactive ternary polymerization flame-retardant polyacrylonitrile fiber comprises the following steps: S1, preparing a phosphorus-containing reactive monomer; S2, mixing acrylonitrile, a phosphorus-containing reactive monomer, a silicon-containing reactive monomer, a free radical initiator and an organic solvent, and carrying out free radical copolymerization in an inert atmosphere to obtain a phosphorus-silicon-containing reactive ternary copolymer polyacrylonitrile copolymer; S3, preparing spinning solution from the phosphorus-silicon-containing reactive ternary copolymer polyacrylonitrile copolymer obtained in the step S2, performing wet spinning or dry-jet wet spinning, entering a coagulating bath, and performing water washing, drafting and drying to obtain the flame-retardant polyacrylonitrile fiber. Preferably, the phosphorus-containing reactive monomer is a reactive monomer containing both a free-radically polymerizable unsaturated group a and a phosphorus-containing functional group; The free radical polymerizable unsaturated group A is selected from one or more of vinyl, allyl, acrylate, methacrylate, acrylamide or methacrylamide; The phosphorus-containing functional group is selected from one or more of a phosphate group, a phosphonate amide group or a phosphonate amide group. Preferably, the phosphorus-containing reactive monomer is an acid type, a partially neutralized salt or a fully neutralized salt, the cation