Radiation-sensitive crosslinking agent and method for producing the same

Abstract

The application discloses a radiation-sensitive crosslinking agent, which is characterized in that the crosslinking agent contains radiation-sensitive dynamic bonds which are easy to break after high-energy irradiation to generate stable free radicals. The irradiation crosslinking bonds of the polymer can be balanced, so that the structural performance of the polymer is stable during irradiation. The crosslinking structure of the material contains phenyl conjugated acylhydrazone bonds which are sensitive to high-energy irradiation and phenylboronic acid groups which are sensitive to active oxygen free radicals generated by radiation. When the gel is irradiated by high-energy rays at room temperature, the broken dynamic covalent bonds and the crosslinking points generated by radiation reach a balance, and the stability of the performance can be maintained macroscopically.

Description

Technical Field

[0001] This invention relates to the field of radiation self-healing materials, specifically to a radiation-sensitive crosslinking agent and its preparation method. Background Technology

[0002] Radiation-crosslinked polymers exhibit aging phenomena such as hardening and reduced mechanical properties after being irradiated with high-energy rays. This is because the radiation generates macromolecular free radicals, which reorganize the material, increasing the number of crosslinking points within the material, i.e., increasing the crosslinking density. For example, polyvinyl alcohol aqueous solutions crosslink after being irradiated with gamma rays. As the absorbed dose increases, the crosslinking density increases, and the polyvinyl alcohol hydrogel undergoes severe shrinkage and hardening [Chang, S.; Wang, B.; Liu, Y.; Li, Z.; Hu, X.; Zhang, X.; Zhang, H., Radiation-assistant preparation of highly conductive, transparent and self-healing hydrogels with triple-network structure. Polymer 2020, 188, 122156.]. A common approach to improving the radiation resistance of materials is to introduce radiation-resistant additives into the polymer, such as compounds containing fused ring structures, compounds containing heavy metal elements such as lead and tungsten, and compounds with free radical scavenging functions; or to directly introduce radiation-resistant structures into the polymer molecular chain. However, existing methods have limited effect on improving the radiation resistance of materials, and the introduction of additives can have adverse effects on the original structural properties of materials.

[0003] The use of radiation-sensitive dynamic bonds for the recycling of epoxy resins has been reported [CN 110218294 A], but research on the use of radiation-sensitive dynamic bonds for the self-repair of materials aging caused by high-energy radiation is still blank.

[0004] Starting with molecular design, a high-energy radiation-sensitive crosslinking agent was designed to introduce dynamic covalent bonds into the crosslinking network, allowing the number of covalent crosslinked structures to maintain a dynamic balance during continuous irradiation, thus preserving the mechanical properties of the material. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides a radiation-sensitive crosslinking agent and a method for preparing the same.

[0006] This invention provides a radiation-sensitive crosslinking agent, characterized in that the crosslinking agent contains radiation-sensitive dynamic bonds that are easily broken upon high-energy irradiation, generating stable free radicals. This balances the irradiation-induced crosslinking bonds in the polymer, thereby maintaining the structural and performance stability of the polymer during irradiation. The crosslinking structure of the material contains phenyl conjugated hydrazone bonds sensitive to high-energy irradiation and phenylboronic acid groups sensitive to the reactive oxygen species (ROS) free radicals produced by radiation. At room temperature, when the gel is irradiated with high-energy rays, the broken dynamic covalent bonds and the crosslinking points generated by radiation reach equilibrium, thus maintaining macroscopic performance stability.

[0007] Furthermore, the crosslinking agent contains phenyl conjugated hydrazone bonds and phenylboronic acid groups; it also contains a structure sensitive to radiation-induced reactive oxygen species (ROS). The general molecular formula of the crosslinking agent is:

[0008]

[0009] Furthermore, R1 is one of the following: cycloalkylene group, cycloalkylene group, heterocycloalkylene group, cycloalkylene heterocycloalkylene group, cycloalkylene heterocycloalkylene group, cycloalkylene group, cycloalkylene group, cycloalkylene group, cycloalkylene heterocycloalkylene group, heterocycloalkylene group, cycloalkylene heterocycloalkylene group, aromatic group, cycloalkylene aromatic group, cycloalkylene aromatic group, heteroaromatic group, cycloalkylene aromatic group, secondary amine cycloalkylene secondary amine, secondary amine heterocycloalkylene secondary amine, secondary amine cycloalkylene secondary amine, secondary amine heterocycloalkylene secondary amine, secondary amine aromatic secondary amine, secondary amine heteroaromatic secondary amine, secondary amine heterocycloalkylene secondary amine, secondary amine heteroaromatic secondary amine, secondary amide heterocycloalkylene secondary amide, secondary amide cycloalkylene secondary amide, secondary amide aromatic secondary amide, secondary amide heteroaromatic secondary amide, oxonyleneoxy, oxonyleneoxy, oxonyleneoxy, oxonyleneoxy, oxaromaticoxy, and disulfide bond.

[0010] Furthermore, R2 is one of hydrogen atom, alkyl, cycloalkyl, heterocyclic, heterocyclic alkyl, alkenyl, cycloalkenyl, aromatic, heteroaromatic, alkanealkyl, alkynyl, alkylenealkyl, alkylenealkylenealkyl, alkenyl, alkylenealkylenealkyl, alkynyl or alkylenealkylenealkylene.

[0011] Furthermore, the phenylboronic acid group is located at any substitution position of the phenyl group.

[0012] In addition, the present invention also provides a method for preparing the aforementioned radiation-sensitive crosslinking agent, characterized in that the crosslinking agent is generated by an amine-aldehyde condensation reaction between a hydrazine derivative and a benzoyl derivative.

[0013] Furthermore, the hydrazine derivative is compound I, which is: The benzoyl derivative is compound II, and compound II is: The molar ratio of compound I to compound II is 1:2.

[0014] Furthermore, the solvent used in the reaction is at least one of water, ethanol, methanol, butanol, tetrahydrofuran, and dimethyl sulfoxide.

[0015] Furthermore, the reaction temperature is 40-120℃.

[0016] The high-energy radiation-sensitive crosslinking agent of this invention has a molecular structure containing two radiation-sensitive phenyl conjugated hydrazone bonds, which improves the responsiveness of the crosslinking agent to high-energy radiation. Introducing high-energy radiation-sensitive dynamic bonds such as hydrazone bonds and disulfide bonds into the polymer as crosslinking structures is a dynamic dissipation strategy for radiation-crosslinked polymer materials that age due to excessive crosslinking during irradiation.

[0017] Furthermore, this invention also provides a high-energy ray irradiation self-healing material based on the aforementioned radiation-sensitive crosslinking agent, comprising a crosslinking agent and a polymer substrate. The crosslinking agent and the polymer substrate are crosslinked in a certain proportion, and the crosslinking structure contains radiation-sensitive dynamic bonds. These bonds crosslink with the substrate through chemical dynamic bonds to generate an irradiation self-healing polymer material. At room temperature, the material maintains stable properties and performance when exposed to high-energy irradiation. The crosslinking structure is as follows:

[0018]

[0019] Furthermore, the crosslinking structure consists of dynamic phenylboronic acid bonds. The hydroxyl groups of the polymer substrate undergo transesterification with the phenylboronic acid groups of the crosslinking agent, or the epoxy structure of the substrate undergoes a condensation reaction with the phenylboronic acid groups of the crosslinking agent, yielding a radiation-self-healing material with phenylboronic esters as the crosslinking structure. Further, the polymer substrate is a radiation-crosslinked polymer material whose main chain contains at least one of hydroxyl, epoxy, or electron-rich nitrogen atom structures.

[0020] Furthermore, the polymer substrate is at least one of cellulose, chitosan, hyaluronic acid, sodium alginate, agar, polyvinyl alcohol, 1,3-diepoxybutane, and epoxy resin.

[0021] Furthermore, the molar ratio of boric acid groups to polymer reactive groups in the crosslinking agent is 1:1 to 1:1000.

[0022] In addition, the present invention also provides a radiation self-healing hydrogel, characterized in that it comprises the aforementioned high-energy ray irradiation self-healing material.

[0023] In addition, the present invention also provides a method for preparing a radiation self-healing hydrogel, characterized in that the crosslinking agent in the aforementioned high-energy ray irradiation self-healing material is mixed with a polymer substrate in a solvent in an appropriate ratio and then crosslinked.

[0024] In addition, the present invention also provides a radiation self-healing aerogel, characterized in that it comprises the aforementioned radiation self-healing hydrogel.

[0025] In addition, the present invention also provides a method for preparing a radiation self-healing aerogel, characterized in that the aforementioned radiation self-healing hydrogel is obtained by freeze-drying or supercritical drying.

[0026] The principle and beneficial effects of this invention are as follows:

[0027] 1. The crosslinking agent molecule contains two radiation-sensitive phenyl conjugated hydrazone bonds, which improves the crosslinking agent's responsiveness to high-energy irradiation. 2. The crosslinking agent structure contains phenylboronic acid. The hydroxyl groups of the borate ester bond have good compatibility with polymer substrates containing epoxy groups and hydroxyl groups. Simultaneously, the reaction conditions are mild and bond formation is rapid. 3. This invention uses radiation-sensitive dynamic bonds to modify radiation-crosslinked polymer materials. Introducing radiation-sensitive dynamic bonds such as hydrazone bonds into the polymer as crosslinking structures addresses the dissipation of crosslinking aging. 4. Choosing the borate ester structure as the crosslinking point has good compatibility with gel precursors containing hydroxyl, epoxy, and electron-rich nitrogen atom structures. It can be used as a crosslinking structure to introduce radiation-sensitive dynamic bonds, extending the material's service life. 5. Materials crosslinked using borate ester bonds are easy to mold and can be made into different shapes. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the 1H NMR spectrum detection results of the crosslinking agent I prepared in Example 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the paramagnetic resonance spectrum of the crosslinking agent prepared in Example 1 of the present invention before and after irradiation, and the crosslinking agent used in the comparative example;

[0030] Figure 3 This is a schematic diagram comparing the mechanical properties of the radiation self-healing gel I prepared in Example 3 of the present invention and the comparative sample hydrogel I prepared in Comparative Example 1.

[0031] Figure 4 This is a schematic diagram of infrared spectral detection of crosslinking agent I before and after γ-ray irradiation in Example 1 of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be further explained below with reference to examples, making the implementation purpose, technical solution and advantages clearer. Unless otherwise specified, the reagents or instruments used are considered to be conventional products that can be purchased commercially.

[0033] The high-energy irradiation self-healing hydrogels and aerogels of this invention contain radiation-sensitive conjugated hydrazone bonds and radiation-product ROS-sensitive phenylboronic acid structures as crosslinking points. When the material is irradiated, the broken dynamic covalent bonds and the crosslinking points generated by radiation reach equilibrium, and it is expected that the polymer material can maintain macroscopic performance stability, thereby achieving self-healing from irradiation aging and extending the service life of the material under continuous irradiation.

[0034] This invention provides a radiation-sensitive crosslinking agent, characterized in that the crosslinking agent contains radiation-sensitive dynamic bonds that are easily broken upon high-energy irradiation, generating stable free radicals. This balances the irradiation-induced crosslinking bonds in the polymer, thereby maintaining the structural and performance stability of the polymer during irradiation. The crosslinking structure of the material contains phenyl conjugated hydrazone bonds sensitive to high-energy irradiation and phenylboronic acid groups sensitive to the reactive oxygen species (ROS) free radicals produced by radiation. At room temperature, when the gel is irradiated with high-energy rays, the broken dynamic covalent bonds and the crosslinking points generated by radiation reach equilibrium, thus maintaining macroscopic performance stability.

[0035] Furthermore, the crosslinking agent contains phenyl conjugated hydrazone bonds and phenylboronic acid groups; it also contains a structure sensitive to radiation-induced reactive oxygen species (ROS). The general molecular formula of the crosslinking agent is:

[0036]

[0037] Furthermore, R1 is one of the following: cycloalkylene group, cycloalkylene group, heterocycloalkylene group, cycloalkylene heterocycloalkylene group, cycloalkylene heterocycloalkylene group, cycloalkylene group, cycloalkylene group, cycloalkylene group, cycloalkylene heterocycloalkylene group, heterocycloalkylene group, cycloalkylene heterocycloalkylene group, aromatic group, cycloalkylene aromatic group, cycloalkylene aromatic group, heteroaromatic group, cycloalkylene aromatic group, secondary amine cycloalkylene secondary amine, secondary amine heterocycloalkylene secondary amine, secondary amine cycloalkylene secondary amine, secondary amine heterocycloalkylene secondary amine, secondary amine aromatic secondary amine, secondary amine heteroaromatic secondary amine, secondary amine heterocycloalkylene secondary amine, secondary amine heteroaromatic secondary amine, secondary amide heterocycloalkylene secondary amide, secondary amide cycloalkylene secondary amide, secondary amide aromatic secondary amide, secondary amide heteroaromatic secondary amide, oxonyleneoxy, oxonyleneoxy, oxonyleneoxy, oxonyleneoxy, oxaromaticoxy, and disulfide bond.

[0038] Furthermore, R2 is one of hydrogen atom, alkyl, cycloalkyl, heterocyclic, heterocyclic alkyl, alkenyl, cycloalkenyl, aromatic, heteroaromatic, alkanealkyl, alkynyl, alkylenealkyl, alkylenealkylenealkyl, alkenyl, alkylenealkylenealkyl, alkynyl or alkylenealkylenealkylene.

[0039] Furthermore, the phenylboronic acid group is located at any substitution position of the phenyl group.

[0040] In addition, the present invention also provides a method for preparing the aforementioned radiation-sensitive crosslinking agent, characterized in that the crosslinking agent is generated by an amine-aldehyde condensation reaction between a hydrazine derivative and a benzoyl derivative.

[0041] Furthermore, the hydrazine derivative is compound I, which is: The benzoyl derivative is compound II, and compound II is: The molar ratio of compound I to compound II is 1:2.

[0042] Furthermore, the solvent used in the reaction is at least one of water, ethanol, methanol, butanol, tetrahydrofuran, and dimethyl sulfoxide.

[0043] Furthermore, the reaction temperature is 40-120℃.

[0044] The high-energy radiation-sensitive crosslinking agent of this invention has a molecular structure containing two radiation-sensitive phenyl conjugated hydrazone bonds, which improves the responsiveness of the crosslinking agent to high-energy radiation. Introducing high-energy radiation-sensitive dynamic bonds such as hydrazone bonds and disulfide bonds into the polymer as crosslinking structures is a dynamic dissipation strategy for radiation-crosslinked polymer materials that age due to excessive crosslinking during irradiation.

[0045] Furthermore, this invention also provides a high-energy ray irradiation self-healing material based on the aforementioned radiation-sensitive crosslinking agent, comprising a crosslinking agent and a polymer substrate. The crosslinking agent and the polymer substrate are crosslinked in a certain proportion, and the crosslinking structure contains radiation-sensitive dynamic bonds. These bonds crosslink with the substrate through chemical dynamic bonds to generate an irradiation self-healing polymer material. At room temperature, the material maintains stable properties and performance when exposed to high-energy irradiation. The crosslinking structure is as follows:

[0046]

[0047] Furthermore, the crosslinking structure consists of dynamic phenylboronic acid bonds. The hydroxyl groups of the polymer substrate undergo transesterification with the phenylboronic acid groups of the crosslinking agent, or the epoxy structure of the substrate undergoes a condensation reaction with the phenylboronic acid groups of the crosslinking agent, yielding a radiation-self-healing material with phenylboronic esters as the crosslinking structure. Further, the polymer substrate is a radiation-crosslinked polymer material whose main chain contains at least one of hydroxyl, epoxy, or electron-rich nitrogen atom structures.

[0048] Furthermore, the polymer substrate is at least one of cellulose, chitosan, hyaluronic acid, sodium alginate, agar, polyvinyl alcohol, 1,3-diepoxybutane, and epoxy resin.

[0049] Furthermore, the molar ratio of boric acid groups to polymer reactive groups in the crosslinking agent is 1:1 to 1:1000.

[0050] In addition, the present invention also provides a radiation self-healing hydrogel, characterized in that it comprises the aforementioned high-energy ray irradiation self-healing material.

[0051] In addition, the present invention also provides a method for preparing a radiation self-healing hydrogel, characterized in that the crosslinking agent in the aforementioned high-energy ray irradiation self-healing material is mixed with a polymer substrate in a solvent in an appropriate ratio and then crosslinked.

[0052] In addition, the present invention also provides a radiation self-healing aerogel, characterized in that it comprises the aforementioned radiation self-healing hydrogel.

[0053] In addition, the present invention also provides a method for preparing a radiation self-healing aerogel, characterized in that the aforementioned radiation self-healing hydrogel is obtained by freeze-drying or supercritical drying.

[0054] Example 1

[0055] Preparation of crosslinking agent I

[0056]

[0057] 4-Acetylphenylboronic acid (3.279 g, 20 mmol) was mixed with carbazide (0.901 g, 10 mmol) and ethanol was used as solvent. The mixture was refluxed at 55 °C for 14 hours. Hydrochloric acid was then added dropwise, and a white precipitate was formed. The white precipitate was then washed with water, methanol, and water in sequence, and then dried under vacuum to constant weight to obtain pure crosslinking agent I.

[0058] Example 2

[0059] Preparation of crosslinking agent II

[0060]

[0061] The synthesis experiment was carried out in a Schlenk reaction flask under nitrogen protection. Dimethyl 3,3'-dithiodipropionate (1.0 g, 4.2 mmol) was dissolved in 50 mL of ethanol, stirred at room temperature, and hydrazine hydrate (1.25 eq, 0.525 g, 10.5 mmol) was added dropwise. After stirring at room temperature for 4 h, the mixture was heated to 60 °C in a water bath and refluxed for 12 h. After the reaction was completed, the mixture was cooled to room temperature, and a white solid precipitated out. The solid was filtered using a glass frit funnel to obtain a filter cake. The filter cake was washed twice each with a mixed solvent of methanol and diethyl ether. The product was dried under vacuum at 40 °C to constant weight to obtain 3,3'-dithiodipropionate dihydrazide.

[0062] 3,3'-dithiodipropionic acid dihydrazide (1 eq) and 4-acetylphenylboronic acid (2 eq) were mixed and reacted under reflux at 55°C for 14 h using an ethanol-tetrahydrofuran mixed solvent. The mixture was then rotary evaporated until no solvent remained and dried under vacuum to constant weight to obtain crosslinking agent II.

[0063] Example 3

[0064] This embodiment provides a method for preparing a radiation self-healing gel material through mixing.

[0065] Radiation self-healing gel can be prepared by a mixing method: a crosslinking agent I aqueous solution is rapidly mixed with a polyvinyl alcohol aqueous solution in a certain proportion and allowed to stand to obtain a gel.

[0066] 5g of crosslinking agent I was dissolved in 100ml of 0.35mol / L sodium hydroxide aqueous solution. Then, 5ml of the crosslinking agent solution was mixed with 5ml of 15wt% polyvinyl alcohol aqueous solution to obtain radiation self-healing hydrogel I.

[0067] Furthermore, the method for preparing the crosslinking agent solution is as follows: a certain mass of crosslinking agent is dissolved in a 4 g / L NaOH aqueous solution to prepare a solution with a crosslinking agent mass fraction of 5%.

[0068] Furthermore, the mass fraction of the gel precursor is 10%.

[0069] Furthermore, the crosslinking agent solution and the gel precursor are mixed in equal volumes.

[0070] Furthermore, the cross-linking reaction temperature is 80℃.

[0071] 5g of crosslinking agent I was dissolved in 100ml of 0.1mol / L sodium hydroxide aqueous solution. Then, 5ml of crosslinking agent solution was rapidly mixed with 5ml of 10wt% polyvinyl alcohol aqueous solution and stirred to obtain radiation self-healing hydrogel I. The ratio of the number of hydroxyl moles of the crosslinking agent to the number of hydroxyl moles of the gel precursor was 1:10.

[0072] The elongation at break of the irradiated self-healing hydrogel I material in Example 3 showed an increasing trend. When the absorbed dose was 20 kGy, the elongation at break was 107% of the initial value, and when the absorbed dose was 50 kGy, the elongation at break was 144% of the initial value.

[0073]

[0074] Example 4

[0075] This embodiment provides a method for preparing radiation-self-healing hydrogel materials through mixing.

[0076] 6.9399 g of crosslinking agent II was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. Then, 2 ml of the crosslinking agent solution was mixed with 5 ml of 10 wt% polyvinyl alcohol aqueous solution to obtain radiation self-healing gel II. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:10.

[0077] The elongation at break of the radiation self-healing hydrogel II material in Example 4 remained stable. When the absorbed dose was 20 kGy, the elongation at break was 93% of the initial value, and when the absorbed dose was 50 kGy, the elongation at break was 88% of the initial value.

[0078] Example 5

[0079] This embodiment provides a method for preparing radiation-self-healing hydrogel materials through mixing.

[0080] 5g of crosslinking agent I was dissolved in 100ml of 0.1mol / L sodium hydroxide aqueous solution. Then, 5ml of the crosslinking agent solution was rapidly mixed with 5ml of 20wt% hyaluronic acid (HA) aqueous solution and stirred to obtain radiation self-healing hydrogel III. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:100.

[0081] The elongation at break of the radiation self-healing hydrogel III material in Example 5 remained stable. When the absorbed dose was 20 kGy, the elongation at break was 103% of the initial value, and when the absorbed dose was 50 kGy, the elongation at break was 91% of the initial value.

[0082] Example 6

[0083] This embodiment provides a method for preparing radiation-self-healing hydrogel materials through mixing.

[0084] 6.9399 g of crosslinking agent II was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. Then, 5 ml of the crosslinking agent solution was rapidly mixed with 5 ml of 20 wt% hyaluronic acid (HA) aqueous solution and stirred to obtain radiation self-healing hydrogel IV. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:100.

[0085] The elongation at break of the radiation self-healing hydrogel IV material in Example 6 remained stable. When the absorbed dose was 20 kGy, the elongation at break was 107% of the initial value, and when the absorbed dose was 50 kGy, the elongation at break was 95% of the initial value.

[0086] Example 7

[0087] This embodiment provides a method for preparing radiation-self-healing hydrogel materials through mixing.

[0088] 1 g of crosslinking agent I was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. At 60 °C, 5 ml of the crosslinking agent solution was rapidly mixed with 5 ml of 30 wt% agar aqueous solution and stirred to obtain radiation self-healing hydrogel V. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:1000.

[0089] The elongation at break of the radiation self-healing hydrogel V material in Example 7 remained stable. When the absorbed dose was 20 kGy, the elongation at break was 104% of the initial value, and when the absorbed dose was 50 kGy, the elongation at break was 90% of the initial value.

[0090] Example 8

[0091] This embodiment provides a method for preparing radiation-self-healing hydrogel materials through mixing.

[0092] 1.39 g of crosslinking agent II was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. At 60 °C, 5 ml of the crosslinking agent solution was rapidly mixed with 5 ml of 30 wt% agar aqueous solution and stirred to obtain radiation self-healing hydrogel VI. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:1000.

[0093] The elongation at break of the radiation self-healing hydrogel VI material in Example 8 remained stable. When the absorbed dose was 20 kGy, the elongation at break was 104% of the initial value, and when the absorbed dose was 50 kGy, the elongation at break was 114% of the initial value.

[0094] Example 9

[0095] This embodiment provides a method for preparing radiation-self-healing epoxy hydrogels.

[0096] Crosslinking agent I was added to a round-bottom flask and stirred with 0.1 mol / L sodium hydroxide solution at room temperature until it was completely dissolved. Then, the bifunctional epoxy monomer BDE was added to the system. After thorough mixing, the mixture was reacted in a 65°C water bath for 1 hour to obtain radiation-self-healing hydrogel VII. The molar ratio of the hydroxyl groups in the crosslinking agent to the epoxy groups in the gel precursor was 2:3.

[0097] The elongation at break of the radiation self-healing hydrogel VII in Example 9 remained stable. When the absorbed dose was 20 kGy, the elongation at break was 123% of the initial value, and when the absorbed dose was 50 kGy, the elongation at break was 95% of the initial value.

[0098] Example 10

[0099] This embodiment provides a method for preparing radiation-self-healing epoxy resin.

[0100] Self-healing epoxy resin can be prepared as follows: In a mixed solvent of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF), crosslinking agent I and bisphenol A type epoxy resin are added sequentially, heated to react, poured into a mold, and after removing the residual solvent, heated to cure, thus obtaining radiation self-healing epoxy resin.

[0101] Furthermore, the mass ratio of DMF to THF in the mixed solvent is 1:4.

[0102] Furthermore, the molar ratio of epoxy groups to hydroxyl groups in the bisphenol A type epoxy resin is 1:1.

[0103] Furthermore, the temperature of the heating reaction system is 80-90℃.

[0104] Furthermore, the heating and curing temperature is 120℃, and the curing time is 2 hours.

[0105] Add 0.9583g of crosslinking agent I to 5g DMF and 20g THF, and stir at room temperature until crosslinking agent I is completely dissolved. Then add 0.9058g of bisphenol A epoxy resin (DGEBA, E51) to the system. Heat the system to 90℃ and stir for 5 hours to obtain a pale yellow prepolymer solution. After removing the solvent THF by rotary evaporation, take a portion of the prepolymer liquid into a mold and vacuum dry in a 70℃ vacuum drying oven for 1 hour to remove residual DMF. Then place it in a 100℃ forced-air oven for 2 hours to react and cure, obtaining modified epoxy resin I. The molar ratio of hydroxyl groups in the crosslinking agent to the molar ratio of epoxy groups in the resin prepolymer is 1:1.

[0106] The elongation at break of modified epoxy resin I can remain stable. When the absorbed dose is 20 kGy, the elongation at break is 98% of the initial value, and when the absorbed dose is 50 kGy, the elongation at break is 94% of the initial value.

[0107]

[0108] Example 11

[0109] This embodiment provides a method for preparing radiation self-healing foam materials.

[0110] 5g of crosslinking agent I was dissolved in 100ml of 0.1mol / L sodium hydroxide aqueous solution. Then, 5ml of the crosslinking agent solution was rapidly mixed with 5ml of 10wt% polyvinyl alcohol aqueous solution and stirred. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:30. The resulting hydrogel was rapidly frozen at -196℃ until ice crystal growth was complete, and then vacuum dried at room temperature until completely lyophilized. Radiation-self-healing foam material I was obtained.

[0111] The self-healing foam material I maintains a stable compressive modulus after irradiation. When the absorbed dose is 20 kGy, the compressive modulus is 90% of the initial value, and when the absorbed dose is 50 kGy, it is 85% of the initial value.

[0112] Example 12

[0113] This embodiment provides a method for preparing radiation self-healing foam materials.

[0114] 5g of crosslinking agent I was dissolved in 100ml of 0.1mol / L sodium hydroxide aqueous solution. Then, 5ml of the crosslinking agent solution was rapidly mixed with 5ml of 20wt% hyaluronic acid (HA) aqueous solution and stirred. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:100. The resulting hydrogel was rapidly frozen at -196℃ until ice crystal growth was complete, and then vacuum dried at room temperature until completely lyophilized. Radiation-self-healing foam material II was obtained.

[0115] The self-healing foam material II maintains a stable compressive modulus after irradiation. When the absorbed dose is 20 kGy, the compressive modulus is 93% of the initial value, and when the absorbed dose is 50 kGy, it is 84% ​​of the initial value.

[0116] Example 13

[0117] This embodiment provides a method for preparing radiation self-healing foam materials.

[0118] 1 g of crosslinking agent I was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. At 60 °C, 5 ml of the crosslinking agent solution was rapidly mixed with 5 ml of 30 wt% agar aqueous solution and stirred. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:1000. The resulting hydrogel was rapidly frozen at -196 °C until ice crystal growth was complete, and then vacuum dried at room temperature until completely lyophilized. Radiation-self-healing foam material III was obtained.

[0119] The self-healing foam material III maintains a stable compressive modulus after irradiation. When the absorbed dose is 20 kGy, the compressive modulus is 91% of the initial value, and when the absorbed dose is 50 kGy, it is 88% of the initial value.

[0120] Example 14

[0121] This embodiment provides a method for preparing radiation self-healing foam materials.

[0122] Add crosslinking agent I to a round-bottom flask and stir with 0.1 mol / L sodium hydroxide solution at room temperature until crosslinking agent I is completely dissolved. Then add the bifunctional epoxy monomer 1,3-diepoxybutane to the system. After stirring thoroughly, react for 1 h in a water bath at 65 °C. The ratio of the molar number of hydroxyl groups in the crosslinking agent to the molar number of epoxy groups in the gel precursor is 2:3.

[0123] The obtained hydrogel was rapidly frozen at -196℃ until ice crystals grew completely, and then vacuum dried at room temperature until completely freeze-dried. This yielded radiation-self-healing foam material IV. The compressive modulus of self-healing foam material IV remained stable after irradiation; at an absorbed dose of 20 kGy, the compressive modulus was 86% of the initial value, and at an absorbed dose of 50 kGy, it was 80% of the initial value.

[0124] Comparative Example 1

[0125] 4.525 g of 4-acetylphenylboronic acid was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. Then, 5 ml of the 4-acetylphenylboronic acid solution was rapidly mixed with 5 ml of 10 wt% polyvinyl alcohol aqueous solution and stirred to obtain comparative gel I. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:10.

[0126] When the absorbed dose is 20 kGy, the elongation at break is 57% of the initial elongation at break. When the absorbed dose is 50 kGy, the elongation at break is 30% of the initial elongation at break, while the tensile strength decreases significantly.

[0127] Comparative Example 2

[0128] 5 g of 4-acetylphenylboronic acid was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. Then, 5 ml of the 4-acetylphenylboronic acid solution was rapidly mixed with 5 ml of 20 wt% hyaluronic acid (HA) aqueous solution and stirred to obtain comparative gel II. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:100.

[0129] The elongation at break of the comparative gel II showed a rapid decreasing trend. When the absorbed dose was 20 kGy, the elongation at break was 52% of the initial value. When the absorbed dose was 50 kGy, the sample had already broken and its elongation at break could not be measured.

[0130] Comparative Example 3

[0131] 0.838 g of 4-acetylphenylboronic acid was dissolved in 100 ml of 0.1 mol / L sodium hydroxide aqueous solution. At 60 °C, 5 ml of the 4-acetylphenylboronic acid solution was rapidly mixed with 5 ml of 30 wt% agar aqueous solution and stirred to obtain comparative gel III. The molar ratio of hydroxyl groups in the crosslinking agent to those in the gel precursor was 1:1000.

[0132] The elongation at break of the comparative gel III showed a rapid decreasing trend. When the absorbed dose was 20 kGy, the elongation at break was 40% of the initial value. When the absorbed dose was 50 kGy, the sample had already broken and its elongation at break could not be measured.

[0133] Comparative Example 4

[0134] 4-Acetylphenylboronic acid was added to a round-bottom flask and stirred with 0.1 mol / L sodium hydroxide solution at room temperature until completely dissolved. Then, the bifunctional epoxy monomer BDE was added to the system. After thorough mixing, the mixture was reacted in a 65°C water bath for 1 hour to obtain comparative gel IV. The molar ratio of the hydroxyl groups in the crosslinking agent to the epoxy groups in the gel precursor was 2:3.

[0135] The elongation at break of the comparative gel IV showed a rapid decreasing trend. When the absorbed dose was 20 kGy, the elongation at break was 30% of the initial value. When the absorbed dose was 50 kGy, the sample had already broken and its elongation at break could not be measured.

[0136] Comparative Example 5

[0137] Take 40g of bisphenol A type epoxy resin E51 into a container, then add 10g of commercial crosslinking agent, mix and stir evenly, pour into a mold, and let stand for 4 hours to obtain the control sample epoxy resin.

[0138] The materials prepared in the selected examples were analyzed and processed:

[0139] I. Characterization by proton nuclear magnetic resonance (NMR):

[0140] The crosslinking agent I prepared in Example 1 was dissolved in deuterated DMSO solvent at a concentration of 10 mg / ml and detected by 1H NMR spectroscopy.

[0141] The NMR spectrum detection results of the crosslinking agent I prepared in Example 1 are as follows: Figure 1 As shown: 1H NMR (400MHz, DMSO) δ 10.29 (s, 4H), 9.53 (s, 2H), 7.73 (q, J=8.4Hz, 8H), 2.14 (s, 6H), confirming the chemical structure of crosslinking agent I, which was then synthesized.

[0142] II. Paramagnetic Resonance Characterization:

[0143] The crosslinking agent I prepared in Example 1 was subjected to X-ray irradiation treatment, and the crosslinking agent before and after irradiation was subjected to paramagnetic resonance testing.

[0144] Experimental results: The paramagnetic resonance spectra of the crosslinking agent prepared in Example 1 and the crosslinking agent used in the comparative example before and after irradiation are as follows: Figure 2 As shown, the higher the free radical content in the irradiated material, the larger the peak area of ​​its paramagnetic resonance spectrum. The peak area of ​​the sample with an absorbed dose of 540 kGy is larger than that of the sample with an absorbed dose of 20 kGy. This is because after the crosslinking agent is irradiated, the NN bond structure of the phenyl conjugated hydrazone undergoes cleavage to generate phenylimine conjugated free radicals. The phenylimine conjugated groups can stabilize the free radicals generated by the radiation cleavage and inhibit the electron aggregation of free radicals through the electron-withdrawing effect, thereby reducing the crosslinking and recombination of molecular chain segments.

[0145]

[0146] III. Characterization of mechanical properties:

[0147] The radiation self-healing gels prepared in Examples 2-8 and the control sample hydrogel prepared in Comparative Example 1 were cut into dumbbell shapes with dimensions of 35mm × 2mm × 0.6mm. They were then subjected to γ-ray irradiation at 0KGy, 20KGy, and 50KGy, respectively, and tensile tests were performed on the materials before and after irradiation.

[0148] Tensile test:

[0149] Tensile tests were conducted using a tensile testing machine manufactured by Instron, USA, with a 1kN sensor selected. The experiments were performed at room temperature. Dumbbell-shaped specimens, measuring 35mm × 2mm × 0.6mm, were used for testing. All samples were tested at a strain rate of 500mm / min. Tensile strength and ultimate elongation at break were obtained from stress-strain curves. Samples treated with different irradiation doses were tested within the same time period.

[0150] The mechanical properties of the radiation self-healing gel I prepared in Example 3 and the comparative sample hydrogel I prepared in Comparative Example 1 were compared under radiation irradiation with an absorbed dose of 0-100 kGy. Figure 3 As shown.

[0151] With a crosslinking agent concentration of 10%, hydrogel I and the comparative hydrogel I have similar elongation at break, but hydrogel I has a slightly higher tensile strength than the comparative hydrogel I. Figure 3 The mechanical properties of the two hydrogels were compared under different absorbed doses. The results showed that the tensile strength and elongation at break of the control sample hydrogel material decreased significantly under γ-radiation. When the absorbed dose was 20 kGy, the elongation at break was 57% of the initial elongation at break, and when the absorbed dose was 50 kGy, the elongation at break was 30% of the initial elongation at break, while the tensile strength decreased significantly. In contrast, the elongation at break of the irradiated self-healing hydrogel I material in Example 3 showed an increasing trend. When the absorbed dose was 20 kGy, the elongation at break was 107% of the initial elongation at break, and when the absorbed dose was 50 kGy, the elongation at break was 144% of the initial elongation at break.

[0152] IV. Fourier Transform Infrared Characterization:

[0153] The crosslinking agent I prepared in Example 1 and the crosslinking agent II prepared in Example 2 were subjected to 100 KGy γ-ray irradiation treatment, and then the crosslinking agents were detected by Fourier transform infrared spectroscopy.

[0154] The radiation self-healing gels prepared in Examples 2-6 and the control sample hydrogel prepared in Comparative Example 1 were subjected to γ-ray irradiation at 0 kGy, 20 kGy, 50 kGy and 100 kGy, respectively. After freeze-drying the materials, Fourier transform infrared spectroscopy was performed on the materials before and after irradiation.

[0155] Peak positions of various groups in infrared spectrum

[0156] 3300 Ph-B-OH 3350 Ph-OH 1690 C=O 1600 C = N 1280 CN

[0157] in, Figure 4 The infrared spectra of crosslinking agent I before and after γ-ray irradiation are shown. A comparison reveals that at an absorbed dose of 20 kGy, the infrared signals at ~1600 cm⁻¹ and ~3090 cm⁻¹ disappear, corresponding to the stretching signals of the C=N and NH groups, indicating that the NN bond in Ph-C(CH₃)=N-NH⁻ has been broken. The infrared signal at ~3030 cm⁻¹ disappears, corresponding to the stretching signal of the β-hydroxyl group in Ph-B-OH; a new infrared signal appears at ~3350 cm⁻¹, corresponding to the stretching signal of the hydroxyl group in Ph-OH, indicating that the phenylboronic acid structure, upon oxidation in response to ROS, generates phenol and boric acid structures.

[0158] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments; the above descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present invention without departing from the spirit and scope of the present invention, and all such modifications and improvements fall within the scope of the present invention; the scope of protection of the present invention is determined by the appended claims.

Claims

1. A high-energy ray irradiation self-healing material, characterized in that, The high-energy ray irradiation self-healing material comprises a crosslinking agent and a polymer substrate. The crosslinking agent and the polymer substrate are crosslinked in a certain proportion, and the crosslinking structure contains radiation-sensitive dynamic bonds. The molecular structure of the crosslinking agent is as follows: ； The cross-linked structure is a dynamic phenylboronic acid ester bond.

2. The high-energy ray irradiation self-healing material according to claim 1, characterized in that, The polymer substrate is a radiation-crosslinked polymer material whose main chain contains at least one of hydroxyl, epoxy, and electron-rich nitrogen atom structures.

3. The high-energy ray irradiation self-healing material according to claim 1, characterized in that, The polymer substrate is at least one of cellulose, chitosan, hyaluronic acid, sodium alginate, agar, polyvinyl alcohol, 1,3-diepoxybutane, and epoxy resin.

4. The high-energy ray irradiation self-healing material according to claim 1, characterized in that, The molar ratio of the boric acid groups of the crosslinking agent to the reactive groups of the polymer matrix is ​​1:1 to 1:1000.

5. A radiation-self-healing hydrogel, characterized in that, The self-healing material containing any one of claims 1-4 is a high-energy ray irradiation material.

6. A method for preparing a hydrogel to obtain the radiation self-healing hydrogel as described in claim 5, characterized in that, The crosslinking agent in the high-energy ray irradiation self-healing material is mixed with the polymer substrate in a solvent in an appropriate ratio and then crosslinked.

7. A radiation-self-healing aerogel, characterized in that, It contains the radiation self-healing hydrogel as described in claim 5.

8. A method for preparing an aerogel to obtain the radiation self-healing aerogel as described in claim 7, characterized in that, The radiation self-healing hydrogel was obtained by freeze-drying or supercritical drying.

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