Self-repairable high-mechanical-property thin film and preparation method and application thereof

Abstract

The invention relates to a self-repairing high-mechanical-property film and a preparation method and application thereof, and the preparation method comprises the following steps: adding ureido pyrimidone and a chain extender into a solvent to obtain a mixed solution, adding the mixed solution into a polyurethane prepolymer, reacting, and drying to obtain the self-repairing high-mechanical-property film. UPy containing hydrogen bonds is introduced into the polymer to prepare the self-repairing high-mechanical-property film, and the hydrogen bond density can be adjusted by adjusting the UPy content of ureido pyrimidone, so that the composite material has excellent self-healing property; and density hydrogen bonds are introduced to construct a physical cross-linked network, so that the mechanical properties of the composite material can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of self-healing materials, and in particular to a self-repairable high-mechanical-performance film, a preparation method thereof, and an application thereof. Background Art

[0002] The self-healing of polymers can be divided into external-aid healing and intrinsic self-healing. The external-aid self-healing materials mainly rely on the rupture of microcapsules pre-embedded in the materials or coatings to repair the damaged areas. The process is that when the matrix is damaged, the microcapsules will rupture, releasing the healing agent inside. The repair agent contacts the catalyst buried in the matrix and triggers polymerization to repair the damaged part. Because the capsule production is relatively easy, the processing is relatively simple, and it is easier to realize industrialization, so it is also more popular in the research of polymers. However, when the repair agent is consumed, the microcapsules will no longer have the healing function and will cause pores in the matrix, affecting a series of properties of the material. The intrinsic self-healing materials rely on the chemical structure and properties of the body itself to achieve self-healing of damage. It mainly completes self-repair through the breakage and reconnection of reversible covalent bonds or reversible non-covalent bonds. Covalent bonds mainly include reversible disulfide bonds, reversible borate ester bonds, Diels-Alder reactions, etc., and non-covalent bonds mainly include reversible hydrogen bonds, π-π stacking, ionic bonds, metal coordination bonds, etc. Compared with the external-aid self-healing materials, the intrinsic self-healing materials have the advantages of more healing means, repeatability, no need for external catalysts, and mild conditions. Therefore, most of the current research on self-healing materials is intrinsic self-healing.

[0003] Self-repairing materials can effectively restore their original stability and function after damage, can repair physical damage, extend the service life of products, reduce maintenance costs, and are of great significance to sustainable development and environmental protection. However, the current method of achieving self-healing by adding functional carriers inside or on the surface of materials is limited by the number of self-healing times. Secondly, many self-repairing materials show rapid self-healing ability by constructing disulfide bonds, but often have low mechanical strength. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a self-repairable high-mechanical-performance film, a preparation method thereof, and an application thereof. The self-repairable high-mechanical-performance film has good self-healing performance and excellent mechanical properties.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The present invention first provides a preparation method of a self-repairable high-mechanical-performance film, which is characterized in that it includes the following steps: adding ureidopyrimidinone and a chain extender into a solvent to obtain a mixed solution, adding the mixed solution into a polyurethane prepolymer for reaction, and drying to obtain the self-repairable high-mechanical-performance film.

[0007] As a further improvement of the above solution of the present invention, in the self-healing high-mechanical-property film, the content of ureidopyrimidinone is 3 wt% - 5.4 wt%.

[0008] As a further improvement of the above solution of the present invention, the preparation method of ureidopyrimidinone is as follows: a mixture of 2-acetylbutyrolactone, guanidine carbonate, triethylamine, and absolute ethanol is heated under reflux. After the solution turns yellow and turbid, it is filtered, washed, the pH is adjusted to neutral, and then post-treated to obtain ureidopyrimidinone.

[0009] As a further improvement of the above solution of the present invention, the molar ratio of 2-acetylbutyrolactone to guanidine carbonate is 1:1, and the volume ratio of triethylamine to absolute ethanol is 1:4; triethylamine serves as a base catalyst and an acid neutralizer; absolute ethanol serves as a solvent, a temperature control medium, and a side reaction inhibitor;

[0010] and / or, the heating under reflux is carried out at 70 - 85 °C for 10 - 12 h;

[0011] and / or, adjusting the pH to neutral is achieved by adding a hydrochloric acid solution to adjust the pH to 6 - 7.

[0012] As a further improvement of the above solution of the present invention, the preparation method of the polyurethane prepolymer is as follows: a diol is dissolved in a solvent, and diisocyanate and a catalyst are added for reaction to obtain the polyurethane prepolymer.

[0013] As a further improvement of the above solution of the present invention, the diol is polytetrahydrofuran with an average relative molecular mass of 850 g / mol;

[0014] and / or, the diisocyanate is isophorone diisocyanate;

[0015] and / or, the catalyst is dibutyltin dilaurate;

[0016] and / or, the solvent is N,N-dimethylformamide;

[0017] and / or, the reaction is carried out at 70 °C - 85 °C for 1.5 - 2.5 h;

[0018] and / or, the volume ratio of the diol to the solvent is 1:2, and the molar ratio of the diol to the diisocyanate is 1:1.5.

[0019] As a further improvement of the above solution of the present invention, the solvent is N,N-dimethylformamide;

[0020] and / or, the chain extender is 1,4-butanediol;

[0021] and / or, the reaction is carried out at 70 °C - 85 °C for 1.5 - 2.5 h.

[0022] The present invention also provides a self-healing high-mechanical-performance film, which is prepared by the preparation method described above.

[0023] The present invention also provides an application of a self-healing high-mechanical-performance film prepared by the preparation method described above in the encapsulation of flexible electronic devices, the housing and screen of electronic devices, intelligent sensors and actuators, bionic and soft robots.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention prepares a self-healing high-mechanical-performance film by introducing ureidopyrimidinone UPy containing hydrogen bonds into the polymer. The hydrogen bond density can be adjusted by adjusting the content of ureidopyrimidinone UPy. The prepared self-healing high-mechanical-performance film has a certain rheology, so it has excellent self-healing properties. And introducing a high-density hydrogen bond to construct a physical cross-linking network can significantly improve the mechanical properties of the composite material. The prepared film not only shows a fast self-healing ability, but also has excellent mechanical properties.

[0026] 2. The method of the present invention is simple to operate, and the raw materials are simple and easy to obtain. The tensile strength of the prepared self-healing high-mechanical-performance film reaches 17.6 MPa, and the toughness can reach 75.6 MJm -3 , which is 91% higher than the toughness of pure polyurethane, and can completely restore its mechanical properties after self-healing at 80 °C for 1 h. The prepared film has good self-healing properties and excellent mechanical properties, and has broad application prospects in the field of high-strength and high-toughness self-healing materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the infrared spectrum of UPy prepared in Example 1 of the present invention;

[0028] Figure 2 is the nuclear magnetic resonance hydrogen spectrum of UPy prepared in Example 1;

[0029] Figure 3 is the infrared spectrum of pure PU and the PUUPy composite material prepared in Example 1;

[0030] Figure 4 is the tensile schematic diagram of the PUUPy composite material prepared in Example 1;

[0031] Figure 5 is the stress-strain curve of the PUUPy composite materials prepared in Examples 1-4;

[0032] Figure 6 is the flow chart of the shear self-healing and tensile experiment of the PUUPy composite material prepared in Example 1;

[0033] Figure 7 Optical photograph of the self-healing process of the PUUPy composite material prepared in Example 1;

[0034] Figure 8 Stress-strain curves of the PUUPy composite material before and after self-healing in Example 1. Detailed implementation manners

[0035] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0037] Example 1

[0038] This example presents a self-healing high mechanical performance film, and its preparation method includes the following steps:

[0039] (1) Synthesize ureidopyrimidinone

[0040] A mixture of 6.4 g of 2-acetylbutyrolactone, 9 g of guanidine carbonate, 16 mL of triethylamine, and 65 mL of absolute ethanol was refluxed at 80 °C for 12 h, and the solution became yellow and turbid; then filtered, washed several times with ethanol, the solid was dispersed in deionized water, and then the excess triethylamine was neutralized with hydrochloric acid solution, and the pH value was adjusted to 6-7. Finally, filtered, washed alternately with deionized water and ethanol, and dried to obtain ureidopyrimidinone UPy.

[0041] (2) Prepare polyurethane prepolymer

[0042] In a three-necked flask filled with nitrogen, dry polytetrahydrofuran (PTMEG) (8.5 g, 10 mmol) was dissolved in 10 mL of N,N-dimethylformamide (DMF) and heated to 70 °C; then, isophorone diisocyanate (IPDI) (3.33 g, 15 mmol) and dibutyltin dilaurate (DBTDL, 0.025 g) as a catalyst were added, and the reaction was carried out at 70 °C for 2 h to obtain polyurethane prepolymer PU. It should be noted in this step that the polytetrahydrofuran is dried first and nitrogen is introduced into the three-necked flask to provide an anhydrous environment for the preparation of the polyurethane prepolymer to prevent side reactions from occurring. The reaction temperature should not be too high, otherwise the reaction will be too fast and solidify.

[0043] (3) Preparation of self-healing high mechanical performance film

[0044] Then, 3.75 mmol of ureidopyrimidinone UPy (0.634 g) and 1.25 mmol of 1,4-butanediol (BDO, 0.1125 g) prepared in step (1) were mixed into 10 mL of DMF solution to obtain a mixed solution; the mixed solution was added to the polyurethane prepolymer solution prepared in step (2), and the reaction was continued at 70 °C for 2 h to obtain a self-healing high mechanical performance film PUUPy (where the UPy content was 5 wt%), denoted as PUUPy 5 . Finally, the PUUPy composite material was dried in an oven at 80 °C for 12 h and then in a vacuum oven at 60 °C for 24 h

[0045] Figure 1 is the infrared spectrum of UPy prepared in step (1) of this example. From Figure 1 it can be seen that the peak at 3379 cm -1 corresponds to the stretching vibration of the -OH group, and the peak at 1641 cm -1 is caused by the C=O double bond in the isopyrimidine ring. The absorption peak at 3118 cm -1 is related to the N-H bond on the isopyrimidine ring. The stretching vibration peak at 1603 cm -1 belongs to the C=N bond in the isopyrimidine ring, and the stretching vibration peak at 1049 cm -1 belongs to the C-O bond, which proves the successful synthesis of UPy in this example

[0046] Figure 2 is the nuclear magnetic resonance hydrogen spectrum of UPy prepared in step (1) of this example, further proving the successful synthesis of UPy in this example

[0047] Figure 3 are the infrared spectra of the polyurethane prepolymer PU prepared in step (2) and the self-healing high mechanical performance film PUUPy prepared in step (3) of this example. Among them, the increase in the intensity of the carbonyl peak at 1695 cm -1 indicates an enhanced intermolecular hydrogen bond interaction

[0048] Combined with Figure 4 , the self-healing high mechanical performance film PUUPy prepared in step (3) of this example was subjected to a tensile test: using a Shimadzu electronic universal testing machine, under a tensile force of 2000 N, the tensile rate was 1 cm / min; the results showed that it could be stretched to 10 times its original length, having excellent tensile properties

[0049] Example 2

[0050] This example uses the same implementation method as Example 1. The difference from Example 1 is that in step (3) of this example, the dosage of ureidopyrimidinone UPy is 2.5 mmol (0.423 g), and the dosage of 1,4-butanediol is 2.5 mmol (0.225 g). In the finally obtained self-healing high-mechanical-property film PUUPy, the UPy content is 3 wt%, denoted as PUUPy 3 。

[0051] Example 3

[0052] This example uses the same implementation method as Example 1. The difference from Example 1 is that in step (3) of this example, the dosage of UPy is 3.33 mmol (0.563 g), and the dosage of 1,4-butanediol is 1.67 mmol (0.15 g). In the finally obtained self-healing high-mechanical-property film PUUPy, the UPy content is 4 wt%, denoted as PUUPy 4 。

[0053] Example 4

[0054] This example uses the same implementation method as Example 1. The difference from Example 1 is that in step (3) of this example, the dosage of UPy is 4 mmol (0.676 g), and the dosage of 1,4-butanediol is 1 mmol (0.09 g). In the finally obtained self-healing high-mechanical-property film PUUPy, the UPy content is 5.4 wt%, denoted as PUUPy 5.4 。

[0055] Test Example

[0056] The self-healing high-mechanical-property films PUUPy prepared in Examples 1-4 were subjected to a tensile test: using a Shimadzu electronic universal testing machine, under a tensile force of 2000 N, the tensile rate was 1 cm / min; the stress-strain curve as shown in Figure 5 was obtained (the toughness of the material can be evaluated by the area under the stress-strain curve). The results showed that the tensile strength of the PUUPy prepared in Example 1 5 reached 17.6 MPa, and the toughness reached 75.6 MJ m -3 , an increase of 91.6% compared to pure PU; the tensile strength of the PUUPy prepared in Example 2 3 reached 16.2 MPa, but the toughness was only 53.1 MJ m -3 ; the tensile strength of the PUUPy prepared in Example 3 4 reached 16.2 MPa, but the toughness was only 65.5 MJ m -3 ; the tensile strength of the PUUPy prepared in Example 4 5.4Its tensile strength can reach 19.9 MPa, but the toughness is only 61.4 MJ m -3 It can be seen from this that the PUUPy prepared in Example 1 5 has the best mechanical properties, and the tensile strength increases by 2 MPa; while the self-healing high-mechanical-property films prepared in Examples 2-3 have poor mechanical properties. This is because the too low UPy content makes it impossible for the composite material to construct a sufficient density of hydrogen bonds and form an effective physical crosslinking network, resulting in poor mechanical properties; in Example 4, due to the too high UPy content, excessive density of hydrogen bonds is generated inside the composite material, forming excessive physical crosslinking, making the composite material have a very high tensile strength but low toughness.

[0057] To further verify the self-healing performance of the self-healing high-mechanical-property film of the present application, we carried out a tensile experiment on the PUUPy composite material prepared in Example 1 after shearing and self-healing. Combining Figure 6 with, the experimental process was as follows: The PUUPy composite material prepared in Example 1 was sheared in half, and then healed at 80 °C for 1 h. The self-healing process was photographed using a microscope, and the results were as Figure 7 shown; then a tensile experiment was carried out: Using a Shimadzu electronic universal testing machine, under a tensile force of 2000 N, the tensile rate was 1 cm / min; the stress-strain curve as Figure 8 shown was obtained. The results showed that after self-healing at 80 °C for 1 h, the tensile strength of the PUUPy composite material prepared in Example 1 reached the initial state, and the mechanical properties were completely restored, further indicating that the self-healing high-mechanical-property film of the present application has self-healing performance.

[0058] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0059] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A method for preparing a self-repairable film with high mechanical properties, characterized in that: It includes the following steps: The ureidopyrimidone and the chain extender are added into a solvent to obtain a mixed solution, and the mixed solution is added into a polyurethane prepolymer for reaction and dried to obtain a self-repairable film with high mechanical properties.

2. The method for preparing a self-repairable film with high mechanical properties according to claim 1, characterized in that: In the self-repairable film with high mechanical properties, the content of ureido pyrimidone is 3wt%-5.4wt%.

3. The method for preparing a self-repairable film with high mechanical properties according to claim 1, characterized in that: The preparation method of the ureidopyrimidone comprises the following steps: heating a mixture of 2-acetylbutyrolactone, guanidine carbonate, triethylamine and anhydrous ethanol to reflux, filtering the solution after it turns yellow and turbid, washing, adjusting the pH to neutral, and post-treating the solution to obtain the ureidopyrimidone.

4. The method for preparing a self-repairable film with high mechanical properties according to claim 2, characterized in that: The molar ratio of 2-acetylbutyrolactone to guanidine carbonate is 1:1, and the volume ratio of triethylamine to anhydrous ethanol is 1:4; And / or, the heating reflux is reflux at 70-85° C. for 10-12 hours; And / or, the step of adjusting the pH to neutral is to add a hydrochloric acid solution to adjust the pH to 6-7.

5. The method for preparing a self-repairable film with high mechanical properties according to claim 1, characterized in that: The preparation method of the polyurethane prepolymer is as follows: diol is dissolved in a solvent, and diisocyanate and a catalyst are added to react to obtain the polyurethane prepolymer.

6. The method for preparing a self-repairable film with high mechanical properties according to claim 5, characterized in that: The diol is polytetrahydrofuran having an average relative molecular mass of 850 g / mol; and / or, the diisocyanate is isophorone diisocyanate; And / or, the catalyst is dibutyltin dilaurate; And / or, the solvent is NN dimethylformamide; And / or, the reaction is carried out at 70°C-85°C for 1.5-2.5h; And / or, the volume ratio of the diol to the solvent is 1:2, and the molar ratio of the diol to the diisocyanate is 1:1.

5.

7. The method for preparing a self-repairable film with high mechanical properties according to claim 1, characterized in that: The solvent is NN dimethylformamide; And / or, the chain extender is 1,4-butanediol; And / or, the reaction is carried out at 70° C.-85° C. for 1.5-2.5 h.

8. A self-repairable film with high mechanical properties, characterized in that: The method is prepared by the method described in any one of claims 1 to 7.

9. An application of a self-repairable high mechanical performance film prepared by the preparation method according to any one of claims 1 to 7 in the packaging of flexible electronic devices, electronic equipment housings and screens, smart sensors and actuators, bionics and soft robots.

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