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CN-122011503-A - Degradation method of crosslinked polymer material

CN122011503ACN 122011503 ACN122011503 ACN 122011503ACN-122011503-A

Abstract

The invention relates to the technical field of polymer degradation, and discloses a degradation method of a crosslinked polymer material, which comprises the steps of adding at least one of dichloroethane, dichloromethane and chloroform into crushed crosslinked polymer material, swelling by an amphoteric permeation carrier, adding anhydrous ferric trichloride, carrying out constant-temperature permeation, then adding benzaldehyde, triphenylphosphine and/or polyethylene glycol dimethyl ether, carrying out in-situ complexing activation to obtain mother liquor to be reacted, carrying out degradation reaction on the mother liquor to be reacted under the pressure condition of periodic gradient fluctuation of 85-120 ℃ and 0.5-1.5 megapascals, and finally adding a quenching agent into the degradation solution to terminate the reaction, and separating and purifying to obtain an oligomer. According to the invention, through the synergistic effect of swelling permeation, in-situ activation and physical disturbance of pressure fluctuation, the pre-burying and efficient reaction of the catalytic active center in the three-dimensional network are realized, and the preparation method is beneficial to obtaining an oligomer product with narrow molecular weight distribution and complete retention of active end groups.

Inventors

  • SONG SHAOFEI
  • CHEN LIANGYU
  • HE ZIJUN
  • FAN ZHIQIANG

Assignees

  • 浙江大学

Dates

Publication Date
20260512
Application Date
20260313

Claims (10)

  1. 1. The degradation method of the crosslinked polymer material is characterized by comprising the following steps of: S1, adding crushed crosslinked polymer materials into at least one of dichloroethane, dichloromethane and chloroform, and adding an amphoteric osmotic carrier for swelling treatment to obtain a swelling system; S2, adding an iron salt precursor into the swelling system for osmotic treatment to obtain an osmotic system; S3, adding benzaldehyde and at least one of triphenylphosphine and polyethylene glycol dimethyl ether into the permeation system for in-situ complexing activation to obtain mother liquor to be reacted; s4, carrying out degradation reaction on the mother liquor to be reacted under the conditions that the temperature is 85-120 ℃ and the pressure is 0.5-1.5 MPa and the periodic gradient fluctuation exists, so as to obtain degradation liquid; S5, adding a quenching agent into the degradation liquid to terminate the reaction, and separating and purifying to obtain the oligomer.
  2. 2. The degradation method of the crosslinked polymer material according to claim 1, wherein the raw materials are as follows in parts by weight: 100 parts of crushed aggregates of crosslinked polymer materials; 5000 to 15000 parts of at least one of dichloroethane, dichloromethane and chloroform; 5.0 to 8.0 parts of an ampholytic carrier; 3.3 to 40.0 parts of ferric salt precursor; 33.3 to 200.0 parts of benzaldehyde; 3.3 to 10.0 parts of at least one of triphenylphosphine and polyethylene glycol dimethyl ether.
  3. 3. The method for degrading a crosslinked polymer material according to claim 1, wherein in the step S1, the swelling treatment is performed by stirring at 40 to 60 ℃, and the amphoteric penetrating carrier is polyoxyethylene-modified 2-alkyl imidazoline.
  4. 4. The degradation method of a cross-linked polymer material according to claim 1, wherein in the step S2, the permeation is performed at a constant temperature of 40 to 60 ℃ for 4 to 6 hours, and the ferric salt precursor is anhydrous ferric trichloride.
  5. 5. The degradation method of a cross-linked polymer material according to claim 1, wherein in the step S3, the number average molecular weight of the polyethylene glycol dimethyl ether is 400, and the in-situ complexing activation is performed for 2 to 3 hours under stirring at 20 to 25 ℃.
  6. 6. The method according to claim 1, wherein in the step S4, the temperature is raised to the degradation reaction temperature at a rate of 3 ℃ per minute, the degradation reaction lasts for 2 to 24 hours, and the frequency of the periodic gradient fluctuation is 1.0 to 1.5 times per hour.
  7. 7. The method for degrading a crosslinked polymeric material according to claim 3, wherein the ampholytic permeable carrier comprises a hydrophobic carbon chain having 12 to 22 carbon atoms and an addition number of ethylene oxide is 5.0 to 15.0mol, and the method for preparing the ampholytic permeable carrier comprises the steps of: Under the protection of nitrogen, 1.0mol of fatty acid and 1.1 to 1.2mol of diethylenetriamine are reacted for 5 to 8 hours at 145 to 165 ℃ for amidation, and by-product water is removed to obtain an intermediate; Heating to 225-245 ℃, and carrying out dehydration and ring closure under reduced pressure reaction for 4-6 hours under the pressure of minus 0.08MPa to minus 0.095 MPa; Adding potassium hydroxide accounting for 0.4 to 0.7 percent of the mass of the closed-loop product into the closed-loop product, introducing ethylene oxide accounting for 5.0 to 15.0mol, performing polyether modification at 130 to 150 ℃, and neutralizing to obtain the amphoteric osmosis carrier.
  8. 8. The degradation method of a crosslinked polymer material according to claim 1, wherein in the step S1, the crushed crosslinked polymer material is a material containing a sulfide system, and in the step S1, at least one of nano zinc oxide and zinc stearate in an amount of 3.3 to 15.0 parts by weight is synchronously added to perform an anti-poisoning pretreatment.
  9. 9. The method for degrading a crosslinked polymer material according to claim 1, wherein the crushed aggregates of the crosslinked polymer material are crushed aggregates of rubber plugs, and 5.0 to 10.0 parts by weight of dioctyl phthalate is additionally added in the step S1.
  10. 10. The method for degrading a crosslinked polymer material according to claim 1, wherein in the step S5, the quencher is at least one of absolute ethyl alcohol and isopropyl alcohol, and the separation and purification comprises: Obtaining filtrate by at least one of centrifugal separation and rapid silica gel column chromatography, dripping the filtrate into methanol for precipitation, and obtaining the oligomer by at least one of vacuum drying and reduced pressure distillation.

Description

Degradation method of crosslinked polymer material Technical Field The invention relates to the technical field of polymer degradation, in particular to a degradation method of a cross-linked high polymer material. Background The cross-linked polymer material is a polymer material with a three-dimensional network space structure formed by connecting macromolecular chains through covalent bonds, has excellent physical and mechanical properties, thermal stability and chemical solvent resistance, and is widely applied to the industrial fields of tire manufacturing, sealing products, aerospace and the like. The prior art for treating the crosslinked polymer material mainly comprises physical mechanical recovery, high-temperature pyrolysis and chemical solvent degradation, wherein the physical mechanical recovery processes the crosslinked polymer material into rubber powder or particles to be used as a filler through mechanical shearing action, the high-temperature pyrolysis utilizes external heating to promote chemical bond fracture in an anaerobic environment to extract pyrolysis oil and solid products therefrom, and the chemical solvent degradation utilizes a specific solvent and a catalyst to destroy crosslinking points in a pressure vessel to try to reduce the crosslinked polymer material into oligomers. The cross-linked polymer material has compact three-dimensional network structure, obvious mass transfer resistance exists in the process of penetrating the external catalytic center and solvent molecules into the cross-linked polymer material, the mass transfer resistance limiting effect causes the degradation reaction to mainly occur in the surface layer area of the cross-linked polymer material particles, the degradation process is uneven and the reaction efficiency is low, the stable cross-linked chemical bond bonding energy needs to be overcome, the prior art generally adopts a mode of greatly increasing the reaction temperature to drive the reaction, the operation of increasing the reaction temperature causes uncontrollable random fracture and deep oxidation phenomena of a polymer main chain, the random fracture phenomenon causes the molecular weight distribution range of degradation products to be too wide, the active functional groups at the tail ends of the degradation products are decomposed and deactivated, and the cross-linked polymer material cannot be converted into a renewable raw material with high value due to serious damage of the chemical structure and unstable performance of the degradation products. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a degradation method of a cross-linked polymer material, which aims to solve the problems of large mass transfer resistance of a cross-linked network, uneven degradation and loss of activity of a product caused by uncontrollable breakage of a molecular chain under high temperature conditions. In order to achieve the above purpose, the invention is realized by the following technical scheme: The invention provides a degradation method of a cross-linked polymer material, which comprises the following steps: S1, adding crushed crosslinked polymer materials into at least one of dichloroethane, dichloromethane and chloroform, and adding an amphoteric osmotic carrier for swelling treatment to obtain a swelling system; S2, adding an iron salt precursor into the swelling system for osmotic treatment to obtain an osmotic system; S3, adding benzaldehyde and at least one of triphenylphosphine and polyethylene glycol dimethyl ether into the permeation system for in-situ complexing activation to obtain mother liquor to be reacted; S4, carrying out degradation reaction on the mother liquor to be reacted under the conditions that the temperature is 85-120 ℃ and the pressure is 0.5-1.5 MPa and the periodic gradient fluctuation exists, so as to obtain degradation liquid; S5, adding a quenching agent into the degradation liquid to terminate the reaction, and separating and purifying to obtain the oligomer. The technical core of the scheme is that the catalytic active center is accurately pre-buried in the cross-linked network by utilizing the synergistic effect of swelling, permeation, in-situ activation and periodic pressure fluctuation. The mechanism of this inside-out initiated depolymerization is illustrated below: In the initial stage of the treatment, namely in the step S1, the polarity difference of the hydrophobic carbon chain and the polyoxyethylene chain segment in the molecule of the amphoteric osmotic carrier is utilized, so that the wettability of the solvent on the surface of the macromolecule is improved, and more importantly, the auxiliary solvent overcomes the physical resistance of the three-dimensional network and enters the cross-linked network gaps. This process physically swells the otherwise compact structure, thereby providing the necessary free volume for subsequent migration of the active ingredien