A fast self-healing polyolefin material based on hydrogen bond interaction and a preparation method thereof

Abstract

The application discloses a kind of based on hydrogen bond interaction's quick self-repairing polyolefin material and preparation method thereof, the main chain structure of the polyolefin self-repairing material contains the structural unit shown in general formula (I) and general formula (II), side chain structure is the structural unit containing hydrogen bond group, wherein x, y are the positive number satisfying x>0, y>0, x>y, 80%≤x+y≤100%, R is halogen atom, the structural unit of general formula (I) and general formula (II) are connected by covalent bond.The polyolefin self-repairing material of the application introduces hydrogen bond by chemical modification, so that material has physical action and chemical action.Hydrogen bond reversibility and dynamicity enable material to recover its physical and chemical properties in short time, thereby significantly reduce repair time and improve repair efficiency.

Description

Technical Field

[0001] This invention belongs to the field of self-healing, specifically a polyolefin material with self-healing function and its preparation method, particularly a polyolefin self-healing material through the introduction of hydrogen bonds. Background Technology

[0002] Polyolefins are widely used due to their advantages such as good chemical stability, high specific strength, low manufacturing cost, excellent corrosion resistance, and ease of processing and molding. However, these materials inevitably face damage during use, resulting in microcracks and micro-damage. This micro-damage can rapidly develop into large cracks, and in severe cases, lead to material failure, significantly reducing the service life and operational safety of the pipe material. Self-healing polymer materials can spontaneously or under external stimuli repair damage or microcracks through physical or chemical processes, preventing damage from expanding and causing loss of material properties. This effectively extends the service life of the material and improves its safety and reliability.

[0003] Existing self-healing materials mostly rely on structures such as microcapsules to achieve exogenous self-healing, or utilize reversible covalent and non-covalent bond interactions to achieve intrinsic self-healing. However, existing self-healing technologies still suffer from problems such as long repair times and low repair efficiency.

[0004] CN108822750B discloses a polyolefin encapsulating film with self-healing function. Its self-healing mechanism mainly involves introducing reversible hydrogen bonds into the resin material of the polyolefin encapsulating film, endowing the material with special properties of reprocessability and active self-healing. This technology improves the material's self-healing ability through the construction of a hydrogen-bonded cross-linked network. However, this technology also has some drawbacks, such as the self-healing process potentially taking a certain amount of time to complete, and the repair efficiency and post-repair mechanical properties possibly being affected by environmental conditions (such as temperature and humidity).

[0005] Hydrogen bonds, as a non-covalent force, provide a certain degree of mechanical strength, are chemically compatible with polyolefin materials, and do not significantly affect the overall performance of the material. They form and break at room temperature without requiring additional catalysts or energy input, and remain relatively stable under various environmental conditions, contributing to improved practicality and reliability of self-healing materials. The reversibility and dynamic nature of hydrogen bonds allow for self-healing through the design of polymer structures. Summary of the Invention

[0006] The technical problem this invention aims to solve is the long self-healing time and low repair efficiency of polyolefin self-healing materials that utilize physical interactions. By modifying the self-healing polyolefin to introduce hydrogen bonds, and utilizing the reversibility and dynamism of hydrogen bonds, rapid and effective self-healing can be achieved through physical interactions under external stimuli. This provides a polyolefin self-healing material that combines physical and chemical effects, enabling it to have rapid self-healing properties, shorten the self-healing time, improve self-healing efficiency, and work stably under different humidity conditions, thereby improving the material's mechanical properties and environmental adaptability.

[0007] To address the aforementioned problems, this invention provides a polyolefin self-healing material, the main chain of which contains structural units represented by general formulas (I) and (II), and the side chain structure consists of structural units containing hydrogen-bonded groups.

[0008]

[0009] Where x and y are positive numbers satisfying x>0, y>0, x>y, and 80%≤x+y≤100%, R is a halogen atom, and the structural units of general formula (Ⅰ) and general formula (Ⅱ) are connected by covalent bonds.

[0010] The polyolefin self-healing material of the present invention, wherein the structural unit containing hydrogen-bonded groups includes structural units having hydrogen bond acceptors and / or having hydrogen bond donors.

[0011] Introducing hydrogen-bonding groups onto the polymer side chains can be achieved through grafting reactions, such as grafting a monomer containing hydrogen-bonding groups onto the polymer. Optionally, a hydrogen-bonding network can be formed on the side chains using suitable crosslinking agents, such as bifunctional compounds (e.g., diisocyanates), to enhance self-healing capabilities.

[0012] The self-healing polyolefin material of the present invention comprises a urea group (-NHCONH-) and an amide group (-CONH2) as the structural unit containing hydrogen-bonding groups. The urea group, due to its two amino groups acting as hydrogen bond donors and the central amide bond acting as a hydrogen bond acceptor, is thus a good hydrogen bond acceptor and donor. The amide group, having a ketone group and an amino group, can simultaneously accept and provide hydrogen bonds, making it suitable for forming cross-linked structures.

[0013] Specifically, halogens in the polymer backbone can be converted into amino groups, and the resulting amination polymer can be reacted with isophorone diisocyanate (TDI) to form urea linkages. The amination polymer can then be reacted with carboxylic acids or carboxylic acid derivatives (such as acid anhydrides, acid chlorides, etc.) to form amide linkages.

[0014] Adding hydroxylamine carbamates can further generate nitrogen- and oxygen-containing modifying groups. For example, the hydroxylamine group (-NH₂OH) of hydroxylamine carbamate reacts with the carbonyl group (-CO-NH⁻) in urea to form R-NH-CO-NH-CO-NHOH, adding a new hydroxyl group (-OH) and an additional carbamate group (-CO-NHOH) to the original urea group, which can act as both a hydrogen bond donor and acceptor. Hydroxylamine carbamates also react with amide groups to form R-CO-NH-CO-NHOH, introducing an additional carbamate group (-CO-NHOH) to the existing amide group, possessing the ability to act as both a hydrogen bond donor and acceptor. These groups are suitable for self-healing materials, providing polymer materials with additional self-healing capabilities, achieving a recovery effect by rapidly rebuilding the broken hydrogen bond network at the microscopic level.

[0015] Preferably, the molar percentage of urea groups in the polyolefin self-healing material is 5% to 15%, and the molar percentage of amide groups is 3% to 10%.

[0016] The above molar percentages are calculated based on the total amount of monomers in the polyolefin backbone, that is, relative to the total number of moles of all monomers (including non-polar and polar monomers) in the polyolefin backbone.

[0017] More preferably, the molar percentage of urea groups in the polyolefin self-healing material is 8% to 12%, and the molar percentage of amide groups is 4% to 7%.

[0018] The present invention also provides a method for preparing the polyolefin self-healing material as described above, the method comprising the following steps:

[0019] S1. Using a rare earth catalyst to copolymerize a polar olefin monomer and ethylene, a first product containing a halogenated group on the side group is obtained, with the following structural formula:

[0020] In the formula, x and y are positive numbers that satisfy x > 0, y > 0, x > y, and 80% ≤ x + y ≤ 100%; R is a halogen atom;

[0021] S2. The halogen in the first product is converted into an amino group. The resulting amination polymer is reacted with isophorone diisocyanate to form a urea linker. The amination polymer is then reacted with a carboxylic acid or a carboxylic acid derivative to form an amide linker, yielding the second product.

[0022] S3. Hydroxycarbamate is dissolved and added to a reaction vessel containing the second product to obtain the polyolefin self-healing material.

[0023] The method for preparing the polyolefin self-healing material of the present invention, wherein the carboxylic acid or carboxylic acid derivative includes at least one of acid anhydride and acid chloride.

[0024] The method for preparing the polyolefin self-healing material of the present invention, wherein the method for preparing the first product includes:

[0025] ① Under an anhydrous and oxygen-free environment, the rare earth catalyst and polar olefin monomer are dissolved in a three-necked flask containing toluene at a molar ratio of 1:200-1:5000 and stirred.

[0026] ② Evacuate the system, introduce nitrogen gas to ensure an anhydrous and oxygen-free environment, introduce ethylene gas to start the reaction, and after the reaction has been going on for a period of time, stop introducing ethylene gas and add methanol to the system to terminate the reaction.

[0027] ③ Filter to obtain the product, wash with ethanol, and then dry under vacuum to obtain the first product.

[0028] In the preparation method of the polyolefin self-healing material of the present invention, the reaction time in step ② of the preparation method of the first product is 10 min-24 h.

[0029] The method for preparing the polyolefin self-healing material of the present invention, wherein the method for preparing the second product includes:

[0030] ① Mix the first product with sufficient toluene or chloroform until it is completely dissolved, then place it in a reaction vessel, add an appropriate amount of ammonia as an amination agent, and react to ensure that the reaction is mixed evenly;

[0031] ② Under an inert atmosphere, add isophorone diisocyanate to the amination polymer, stir and mix at room temperature, gradually raise the temperature to 80-100℃, and maintain this temperature for 1-2 hours to promote the formation of urea groups. Adjust the stirring speed to 400-600 rpm to ensure sufficient contact and reaction between the reactants.

[0032] ③ Slowly add acid anhydride as a carboxylic acid source to the above reaction system. Under controlled conditions, maintain the temperature at 90-110℃ and continue the reaction for 2-3 hours. Keep the stirring speed at 400-600 rpm to ensure the reaction proceeds uniformly.

[0033] ④ Cool the reaction mixture, filter and wash the reaction product to remove unreacted starting materials and byproducts, and dry under reduced pressure to obtain the second product.

[0034] In the preparation method of the polyolefin self-healing material of the present invention, in the preparation method of the second product, the reaction temperature in step ① is 50-70℃, the reaction time is 2-4 hours, and the stirring speed is 300-500 rpm.

[0035] The preparation method of the polyolefin self-healing material of the present invention, wherein the specific operation in step S3 includes:

[0036] ① Dissolve the hydroxycarbamate using a small amount of organic solvent;

[0037] ② The second product is mixed with the dissolved hydroxylamine carbamate in a reaction vessel, and the reaction is carried out.

[0038] ③ Cool to room temperature, filter and wash, and dry under reduced pressure to obtain the polyolefin self-healing material.

[0039] In the preparation method of the polyolefin self-healing material of the present invention, in step S3, the organic solvent in step ① includes dimethylformamide; and the reaction temperature in step ② is 40-50℃ and the reaction time is 1-2 hours.

[0040] Preferably, the polyolefin self-healing material contains 5% to 15% urea groups, 3% to 10% amide groups, and 4% to 11% hydroxycarbamate added in the reaction.

[0041] The above molar percentages are calculated based on the total amount of monomers in the polyolefin backbone, that is, relative to the total number of moles of all monomers (including non-polar and polar monomers) in the polyolefin backbone.

[0042] More preferably, the urea groups in the polyolefin self-healing material have a molar percentage of 8% to 12%, and the amide groups have a molar percentage of 4% to 7%. The hydroxylamine carbamate added in the reaction has a molar percentage of 5% to 7%. By controlling these proportions, the formation of microphase separation structures can be promoted, enhancing the overall performance of the material and optimizing its self-healing efficiency and environmental adaptability while maintaining the overall mechanical strength of the material.

[0043] The present invention has at least the following beneficial effects:

[0044] (1) The polyolefin self-healing material of the present invention introduces hydrogen bonds through chemical modification, enabling the material to have both physical and chemical effects. The reversibility and dynamism of hydrogen bonds allow the material to restore its physical and chemical properties in a short time, thereby significantly reducing repair time and improving repair efficiency.

[0045] (2) This invention introduces specific proportions of functional groups to enable the material to maintain stable performance under different humidity and temperature conditions, thereby enhancing its environmental adaptability and promoting the formation of microphase separation structures. When the material is damaged, the chain segments at the damaged site can move freely, achieving rapid physical repair through spontaneous chain segment recombination. At the same time, the aggregation of crystalline segments can also improve the self-healing ability of the material to a certain extent. Attached Figure Description

[0046] Figure 1 This is the hydrogen NMR spectrum of the first product in Example 1 of the present invention. Detailed Implementation

[0047] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0048] This invention provides a polyolefin self-healing material, the main chain structure of which contains structural units represented by general formula (I) and general formula (II).

[0049]

[0050] The main chain of the polyolefin self-healing material contains structural units as shown in general formulas (I) and (II), where x and y are positive numbers satisfying x > 0, y > 0, x > y, and 80% ≤ x + y ≤ 100%. R is a halogen atom, and the structural units of general formulas (I) and (II) are connected by covalent bonds.

[0051] The side chain structure of polyolefin self-healing materials consists of structural units containing hydrogen-bonded groups. These hydrogen-bonded structural units include those with hydrogen bond acceptors and / or hydrogen bond donors.

[0052] The self-healing polyolefin material of this invention comprises a copolymer chain obtained by copolymerizing polar / nonpolar olefin monomers. The copolymer has long alternating copolymer segments of polar / nonpolar monomers and short homopolymer segments of nonpolar monomers. The nonpolar homopolymer segments can be arranged in an orderly manner to form a crystalline structure, while the alternating copolymer segments have good flexibility and can move freely. The copolymer can form a microphase separation structure. When the material is damaged, the chain segments at the damaged site can move freely to complete the self-healing process. The aggregation effect of the crystalline segments also enhances the self-healing ability of the material to a certain extent.

[0053] As mentioned above, the main chain of the polyolefin self-healing material is a copolymer obtained by copolymerizing polar / non-polar olefin monomers. In some embodiments, the number average molecular weight of the main chain copolymer is between 40,000 and 500,000, wherein the molar content of polar monomers is greater than 20%, and the glass transition temperature is between -10 and 10°C.

[0054] Structural units containing hydrogen-bonded groups include those with hydrogen bond acceptors and / or hydrogen bond donors, specifically including urea groups (-NHCONH-) and amide groups (-CONH2), etc. The addition of hydroxylamine carbamate can further generate nitrogen- and oxygen-containing modifying groups. The molar percentage of urea groups in the polymer is 5% to 15%, the molar percentage of amide groups is 3% to 10%, and the molar percentage of hydroxylamine carbamate added in the reaction is 4% to 11%. Preferably, the molar percentage of urea groups in the polymer is 8% to 12%, the molar percentage of amide groups is 4% to 7%, and the molar percentage of hydroxylamine carbamate added in the reaction is 5% to 7%.

[0055] Test methods

[0056] Tensile test: The sample is hot-pressed at 100-150℃ to prepare a dumbbell-shaped strip with a length of 12mm, a width of 2mm, and a thickness of 1mm. The strip is then clamped on a tensile testing machine and stretched at a speed of 200mm / min. -1 ;

[0057] Self-healing performance: The sample was cut with a razor, the cut surfaces were kept in contact, and the healing of the cut was observed at different time intervals. Tensile tests were also performed to characterize the mechanical properties of the repaired sample.

[0058] Humidity environment testing: Using an environmental test chamber or climate chamber, set the relative humidity to 50% and 90%, maintain a constant room temperature, and repeat the above tensile test and self-healing performance test.

[0059] Example 1

[0060] Preparation of the first product:

[0061] ① Under an anhydrous and oxygen-free environment, the rare earth catalyst and 1-allyl-4-bromo-2-methoxybenzene were dissolved in a three-necked flask containing toluene at a molar ratio of 1:200, and stirred for 10 minutes at a speed of 500 rpm.

[0062] ② Evacuate the system, introduce nitrogen gas to ensure an anhydrous and oxygen-free environment, introduce ethylene gas, react for 30 minutes, then stop introducing ethylene gas and add methanol to the system to terminate the reaction.

[0063] ③ Filter to obtain the product, wash with ethanol three times, and then dry under vacuum to obtain the first product.

[0064] Preparation of the second product:

[0065] ① Mix 100g of the first product with 260mL of toluene, ensuring complete dissolution, then place the mixture in a reaction vessel and add 25% w / w ammonia. Maintain the reaction temperature at 60℃ for 2 hours, stirring at 300rpm.

[0066] ② Under a nitrogen atmosphere, add 348g of isophorone diisocyanate (TDI) to the amination polymer, stir and mix at room temperature, gradually raise the temperature to 90°C, maintain this temperature for 1 hour, and adjust the stirring speed to 500rpm.

[0067] ③ Slowly add 53.9g of maleic anhydride, keep the temperature at 90℃, and continue the reaction for 2 hours while maintaining a stirring speed of 500rpm.

[0068] ④ Cool the reaction mixture, filter, and wash the reaction product with toluene to remove unreacted starting materials and byproducts. Dry under reduced pressure to obtain the second product.

[0069] Preparation of polyolefin self-healing materials:

[0070] ① Dissolve 91.8g of hydroxylamine carbamate using dimethylformamide.

[0071] ② In a reaction vessel, mix 1000g of the second product with dissolved dimethylformamide. Set the temperature to 40℃ and maintain the reaction for 1 hour to ensure complete reaction.

[0072] ③ Cool to room temperature, filter and wash, and dry under reduced pressure to obtain the polyolefin self-healing material.

[0073] In the aforementioned polyolefin self-healing material, the molar percentage of urea groups is 10%, and the molar percentage of amide groups is 5.5%. The 91.8 g of hydroxylamine carbamate added in the reaction has a calculated molar percentage of 6.1%.

[0074] Example 2

[0075] Preparation of the first product:

[0076] ① Under an anhydrous and oxygen-free environment, the rare earth catalyst and 1-allyl-4-chloro-2-methoxybenzene were dissolved in a three-necked flask containing toluene at a molar ratio of 1:200, and stirred for 15 minutes at a speed of 600 rpm.

[0077] ② Evacuate the system, introduce nitrogen gas to ensure an anhydrous and oxygen-free environment, introduce ethylene gas, react for 45 minutes, then stop introducing ethylene gas and add methanol to the system to terminate the reaction.

[0078] ③ Filter to obtain the product, wash with ethanol four times, and then dry under vacuum to obtain the first product.

[0079] Preparation of the second product:

[0080] ① Mix 120g of the first product with 300mL of toluene, ensuring complete dissolution, then place the mixture in a reaction vessel and add 25% w / w ammonia. Maintain the reaction temperature at 70℃ for 3 hours, stirring at 400rpm.

[0081] ② Under a nitrogen atmosphere, add 370g of isophorone diisocyanate (TDI) to the amination polymer, stir and mix at room temperature, gradually raise the temperature to 95°C, maintain this temperature for 1.5 hours, and adjust the stirring speed to 600rpm.

[0082] ③ Slowly add 56g of maleic anhydride, keep the temperature at 95℃, and continue the reaction for 2.5 hours while maintaining the stirring speed at 600rpm.

[0083] ④ Cool the reaction mixture, filter, and wash the reaction product with toluene to remove unreacted starting materials and byproducts. Dry under reduced pressure to obtain the second product.

[0084] Preparation of polyolefin self-healing materials:

[0085] ① Dissolve 100g of hydroxylamine carbamate using dimethylformamide.

[0086] ② In a reaction vessel, mix 1200g of the second product with dissolved dimethylformamide. Set the temperature to 50℃ and maintain the reaction for 2 hours to fully complete the grafting.

[0087] ③ Cool to room temperature, filter and wash, and dry under reduced pressure to obtain the polyolefin self-healing material.

[0088] In the aforementioned polyolefin self-healing material, the molar percentage of urea groups is 8.9%, and the molar percentage of amide groups is 4.75%. The molar percentage of 100g of hydroxylamine carbamate added in the reaction is calculated to be 5.5%.

[0089] Example 3

[0090] Example 3 was prepared using essentially the same method as Example 1, except that 243.6 g of isophorone diisocyanate (TDI) was added. In the polyolefin self-healing material, the molar percentage of urea groups was 7%.

[0091] Example 4

[0092] Example 4 was prepared using essentially the same method as Example 1, except that 435 g of isophorone diisocyanate (TDI) was added. In the polyolefin self-healing material, the molar percentage of urea groups was 12.5%.

[0093] Example 5

[0094] Example 5 was prepared using essentially the same method as Example 2, except that 35.3 g of maleic anhydride was added. In the polyolefin self-healing material, the molar percentage of amide groups was 3%.

[0095] Example 6

[0096] Example 6 was prepared using essentially the same method as Example 2, except that 88.2 g of maleic anhydride was added. In the polyolefin self-healing material, the molar percentage of amide groups was 7.5%.

[0097] Example 7

[0098] Example 7 was prepared using essentially the same method as Example 1, except that 68 g of hydroxycarbamate was added. The calculated molar percentage was 4.5%.

[0099] Example 8

[0100] Example 8 was prepared using essentially the same method as Example 1, except that 113.3 g of hydroxycarbamate was added. The calculated molar percentage was 7.5%.

[0101] Comparative Example 1

[0102] Comparative Example 1 was prepared using essentially the same method as in Example 1, except that 156.6 g of isophorone diisocyanate (TDI) was added. In the polyolefin self-healing material, the molar percentage of urea groups was 4.5%.

[0103] Comparative Example 2

[0104] Comparative Example 2 was prepared using essentially the same method as in Example 1, except that 539.4 g of isophorone diisocyanate (TDI) was added. In the polyolefin self-healing material, the molar percentage of urea groups was 15.5%.

[0105] Comparative Example 3

[0106] Comparative Example 3 was prepared using essentially the same method as in Example 2, except that 29.4 g of maleic anhydride was added. In the polyolefin self-healing material, the molar percentage of amide groups was 2.5%.

[0107] Comparative Example 4

[0108] Comparative Example 4 was prepared using essentially the same method as in Example 2, except that 123.5 g of maleic anhydride was added. In the polyolefin self-healing material, the molar percentage of amide groups was 10.5%.

[0109] Comparative Example 5

[0110] Comparative Example 5 was prepared using essentially the same method as in Example 1, except that 52.9 g of hydroxycarbamate was added. The calculated molar percentage was 3.5%.

[0111] Comparative Example 6

[0112] Comparative Example 6 was prepared using essentially the same method as in Example 1, except that 173.7 g of hydroxycarbamate was added. The calculated molar percentage was 11.5%.

[0113] Test Results

[0114] Tensile strength, tensile strength after 24 hours of self-healing, tensile strength at 50% relative humidity, tensile strength after 24 hours of self-healing at 50% relative humidity, tensile strength at 90% relative humidity, and tensile strength after 24 hours of self-healing at 90% relative humidity (MPa) of Examples 1-8 and Comparative Examples 1-6

[0115]

[0116] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the present invention.

Claims

1. A self-healing polyolefin material, wherein the main chain structure contains structural units represented by general formulas (I) and (II), and the side chain structure consists of structural units containing hydrogen-bonded groups. Where x and y are positive numbers satisfying x>0, y>0, x>y, and 80%≤x+y≤100%, R is a halogen atom, and the structural units of general formula (Ⅰ) and general formula (Ⅱ) are connected by covalent bonds.

2. The polyolefin self-healing material according to claim 1, characterized in that, The structural unit containing hydrogen-bonded groups includes structural units having hydrogen bond acceptors and / or hydrogen bond donors.

3. The polyolefin self-healing material according to claim 1, characterized in that, The structural unit containing hydrogen-bonded groups includes a urea group (-NHCONH-) and an amide group (-CONH2).

4. The polyolefin self-healing material according to claim 3, characterized in that, The polyolefin self-healing material contains 5% to 15% urea groups and 3% to 10% amide groups in molar percentage.

5. The polyolefin self-healing material according to claim 4, characterized in that, The polyolefin self-healing material contains 8% to 12% urea groups and 4% to 7% amide groups in molar percentage.

6. A method for preparing a polyolefin self-healing material, characterized in that, Includes the following steps: S1. Using a rare earth catalyst to copolymerize a polar olefin monomer and ethylene, a first product containing a halogenated group on the side group is obtained, with the following structural formula: In the formula, x and y are positive numbers that satisfy x > 0, y > 0, x > y, and 80% ≤ x + y ≤ 100%; R is a halogen atom; S2. The halogen in the first product is converted into an amino group. The resulting amination polymer is reacted with isophorone diisocyanate to form a urea linker. The amination polymer is then reacted with a carboxylic acid or a carboxylic acid derivative to form an amide linker, yielding the second product. S3. Hydroxycarbamate is dissolved and added to a reaction vessel containing the second product to obtain the polyolefin self-healing material.

7. The preparation method according to claim 6, characterized in that, The carboxylic acid or carboxylic acid derivative includes at least one of acid anhydride and acid chloride.

8. The preparation method according to claim 6, characterized in that, The method for preparing the first product includes: ① Under an anhydrous and oxygen-free environment, the rare earth catalyst and polar olefin monomer are dissolved in a three-necked flask containing toluene at a molar ratio of 1:200-1:5000 and stirred. ② Evacuate the system, introduce nitrogen gas to ensure an anhydrous and oxygen-free environment, introduce ethylene gas to start the reaction, and after the reaction has been going on for a period of time, stop introducing ethylene gas and add methanol to the system to terminate the reaction. ③ Filter to obtain the product, wash with ethanol, and then dry under vacuum to obtain the first product.

9. The preparation method according to claim 8, characterized in that, In the preparation method of the first product, the reaction time in step ② is 10 min-24 h.

10. The preparation method according to claim 6, characterized in that, The method for preparing the second product includes: ① Mix the first product with sufficient toluene or chloroform until it is completely dissolved, then place it in a reaction vessel, add an appropriate amount of ammonia as an amination agent, and react to ensure that the reaction is mixed evenly; ② Under an inert atmosphere, add isophorone diisocyanate to the amination polymer, stir and mix at room temperature, gradually raise the temperature to 80-100℃, and maintain this temperature for 1-2 hours to promote the formation of urea groups. Adjust the stirring speed to 400-600 rpm to ensure sufficient contact and reaction between the reactants. ③ Slowly add acid anhydride as a carboxylic acid source to the above reaction system. Under controlled conditions, maintain the temperature at 90-110℃ and continue the reaction for 2-3 hours. Keep the stirring speed at 400-600 rpm to ensure the reaction proceeds uniformly. ④ Cool the reaction mixture, filter and wash the reaction product to remove unreacted starting materials and byproducts, and dry under reduced pressure to obtain the second product.

11. The preparation method according to claim 10, characterized in that, In the preparation method of the second product, the reaction temperature in step ① is 50-70℃, the reaction time is 2-4 hours, and the stirring speed is 300-500 rpm.

12. The preparation method according to claim 6, characterized in that, The specific operations in step S3 include: ① Dissolve the hydroxycarbamate using a small amount of organic solvent; ② The second product is mixed with the dissolved hydroxycarbamate in a reaction vessel, and the reaction is carried out. ③ Cool to room temperature, filter and wash, and dry under reduced pressure to obtain the polyolefin self-healing material.

13. The preparation method according to claim 12, characterized in that, In step S3, the organic solvent mentioned in ① includes dimethylformamide; the reaction temperature mentioned in ② is 40-50℃, and the reaction time is 1-2 hours.

14. The preparation method according to claim 6, characterized in that, The polyolefin self-healing material contains 5% to 15% urea groups, 3% to 10% amide groups, and 4% to 11% hydroxycarbamate added in the reaction.

15. The preparation method according to claim 6, characterized in that, The polyolefin self-healing material contains 8% to 12% urea groups and 4% to 7% amide groups in molar percentage. The hydroxylamine carbamate added during the reaction contains 5% to 7% in molar percentage.

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