A multi-dynamic room temperature self-repairing polyurethane elastomer and a preparation method thereof

Abstract

The present application relates to a kind of multiple dynamic room temperature self-repairing polyurethane elastomer and its preparation method, belong to polyurethane material field, it can reach 26.8MPa on the basis of room temperature self-repairing with high tensile strength.The material can realize efficient self-repairing under mild room temperature condition, and its tensile strength can recover to 15.4MPa.In addition, the damping performance of polyurethane elastomer material is excellent, and in the temperature range close to 80 DEG C, damping factor is greater than 0.3.By introducing the dynamic reversible ketoxime-urethane dynamic chemical bond in polyol, the room temperature self-repairing ability of polyurethane material is given;And this multiple dynamic chemical structure increases the internal friction of polyurethane molecular chain, promotes phase separation, improves the mechanical properties and improves the damping performance of material.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-strength, self-repairing multiple dynamic polyurethane elastomer and its preparation method, belong to polyurethane material field, it can be self-repaired at room temperature on the basis of high mechanical strength. BACKGROUND

[0002] Polyurethane is widely used in various industrial and consumer product fields such as vibration and noise reduction, intelligent sensing and sealing devices due to its rich chemical structure and excellent mechanical properties. The performance of polyurethane can be adjusted by changing its molecular structure or chemical composition, so as to realize different forms such as hard, soft, elastomer, etc. With people's increasingly high requirements for use quality, the self-repairing ability of materials is more and more concerned. However, the improvement of material mechanical properties and the enhancement of self-repairing performance have always been a difficult contradiction to reconcile. At present, the main methods to improve the self-repairing performance of polyurethane elastomer material include adding repair microcapsules and introducing dynamic covalent bonds, etc. Repair microcapsules will release repair substances to repair quickly after the material is damaged, but the limited healing times will affect the long-term use of the material, and the existence of capsules will significantly reduce the mechanical properties of the material. The introduction of dynamic covalent material can give it self-repairing performance through the recovery of dynamic reversible chemical bonds after damage. However, this self-healing usually needs the input of light, heat, pressure or other external conditions, which limits its application scenarios.

[0003] In recent years, polyurethane with self-repairing function has been widely studied. For example, Wei et al. introduced DA bond into polyurethane elastomer by molecular chain design to realize self-healing performance. The results show that the self-repairing rate of polyurethane elastomer with DA bond is 67.56% at 80℃ (Wei Y Y, Ma X Y. The self-healing cross-linked polyurethane by Diels-Alder polymerization. Advances in Polymer Technology, 2018, 37(6): 1987). Song et al. prepared a supramolecular polyurethane elastomer by dynamic covalent boronic ester bond and boron-nitrogen coordination method. The ligand of boron and nitrogen promotes the formation and dissociation of boronic ester bond at room temperature, which enhances the mechanical properties of the material while imparting self-repairing performance to the material. The tensile strength of the prepared sample reaches 10.5MPa, and the strength can reach 5.2MPa after self-repairing for 24h (Song K, Ye W J, Gao X C, Fang H G, Zhang Y Q, Zhang Q, Li X L, Yang S Z, Wei H B, Ding Y S. Synergy between dynamic covalent boronic ester and boron-nitrogen coordination: strategy for self-healing polyurethane elastomers at room temperature with unprecedented mechanical properties. Materials Horizons, 2021, 8(1): 216.). The above two kinds of polyurethane have certain self-repairing performance, but the difficulty of self-repairing at room temperature and the low mechanical strength limit their further application. SUMMARY

[0004] The technical problem solved by the present application is to provide a room temperature self-repairing polyurethane material to overcome the problem that the existing polyurethane material cannot have good mechanical properties and room temperature self-repairing performance.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is:

[0006] A multiple dynamic room temperature self-repairing polyurethane elastomer, the raw materials of the polyurethane elastomer include polyol, diisocyanate, dihydrazine chain extender, catalyst and solvent.

[0007] Among them, the polyol is polyester polyol or polyether polyol.

[0008] The percentage content of each component is, based on the total mass of the raw materials of the polyurethane elastomer being 100%:

[0009] Polyol 40%-70%;

[0010] Diisocyanate 15%-40%;

[0011] Dioxime chain extender 10%-30%;

[0012] Catalyst 0.1%-0.3%;

[0013] The ratio of the amount of solvent to polyol is 10-30 mL: 15 g;

[0014] The polyester polyol is at least one of polycaprolactone glycol, polycarbonate glycol, polyhexylene adipate glycol, and polypropylene adipate glycol, and the molecular weight of the polyester polyol is 600-9000;

[0015] The polyether polyol is at least one of polytetrahydrofuran glycol, polyethylene glycol, and polypropylene glycol, and the molecular weight of the polyether polyol is 600-9000;

[0016] The diisocyanate is at least one of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and diphenylmethane diisocyanate;

[0017] The dioxime chain extender is at least one of butanedione oxime, 2,4-pentanedione oxime, methylglyoxal dioxime, 1,4-benzoquinone dioxime, dichloroethanedione, and biphenylglyoxal oxime;

[0018] The catalyst is at least one of dibutyltin dilaurate, stannous isooctoate, polyethyleneimine, and ethylenediamine;

[0019] The solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, toluene, xylene, dimethyl sulfoxide, and tetrahydrofuran.

[0020] A preparation method of a multiple dynamic room temperature self-repairing polyurethane elastomer, by introducing a dioxime chain extender into a polyol, so that it has a dynamic chemical bond, thereby preparing a multiple dynamic high-strength room temperature self-repairing polyurethane; specifically comprising:

[0021] Step one, mix the dioxime chain extender, 7.5%-30% of the total mass of diisocyanate, half of the total solvent, and the catalyst uniformly, then heat at 60-80°C for 1-6h under the protection of inert gas (argon, nitrogen) atmosphere, and the stirring speed is 100-400r / min, to obtain an isocyanate-terminated prepolymer;

[0022] Step two, after the polyol is dehydrated under vacuum at 100-150 DEG C for 2-6h, it is added to the isocyanate-terminated prepolymer obtained in step one, and heated at 60-80 DEG C for 1-6h to obtain a polyurethane dynamic soft segment;

[0023] Step three, the remaining diisocyanate and solvent are added to the polyurethane dynamic soft segment obtained in step two, and then heated at 60-80 DEG C for 3-24h with a stirring speed of 100-400r / min to obtain a viscous liquid product;

[0024] Step four, the viscous liquid product obtained in step three is heated and dried in a vacuum oven at a drying temperature of 60-100 DEG C for 24-72h to obtain a multiple dynamic room temperature self-repairing polyurethane elastomer.

[0025] The obtained multiple dynamic room temperature self-repairing polyurethane elastomer has vibration and noise reduction performance and can be used in the fields of aerospace or transportation.

[0026] Compared with the prior art, the present application has the following beneficial effects: overcoming the bottleneck that the polyurethane room temperature self-repairing performance and mechanical properties cannot be compatible in the prior art, and proposing a multiple dynamic room temperature self-repairing polyurethane elastomer and a preparation method thereof. The introduction of a room temperature dynamic reversible ketoxime-urethane dynamic chemical bond in the soft segment endows the polyurethane material with room temperature self-repairing ability. The multiple dynamic chemical structure increases the internal friction of the polyurethane molecular chain, promotes phase separation, improves the mechanical properties and enhances the damping performance of the material. The damping factor is greater than 0.3 in the temperature range of 6-80 DEG C, and the material can be applied to vibration and noise reduction. The present application relates to a multiple dynamic room temperature self-repairing polyurethane elastomer and a preparation method thereof, and belongs to the field of polyurethane materials. The material can self-repair at room temperature and has a high tensile strength of 26.8MPa. The material can realize efficient self-repairing at a mild room temperature, and the tensile strength can be restored to 15.4MPa. In addition, the damping performance of the polyurethane elastomer material is excellent, and the damping factor is greater than 0.3 in the temperature range of nearly 80 DEG C. The introduction of a room temperature dynamic reversible ketoxime-urethane dynamic chemical bond in the soft segment endows the polyurethane material with room temperature self-repairing ability. The multiple dynamic chemical structure increases the internal friction of the polyurethane molecular chain, promotes phase separation, improves the mechanical properties and enhances the damping performance of the material. The prepared high-strength multiple dynamic room temperature self-repairing polyurethane elastomer has vibration and noise reduction performance and can be used in the fields of aerospace or transportation, and has a good market prospect. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The synthesis route of the multiple dynamic room temperature self-repairing polyurethane elastomer of the present application is shown in the figure;

[0028] Figure 2 Infrared spectrum of the multiple dynamic room temperature self-repairing elastomer of the present application;

[0029] Figure 3 Tensile strength diagram of the multiple dynamic room temperature self-repairing elastomer of the present application and the comparative example;

[0030] Figure 4 Room temperature self-repairing result diagram of the multiple dynamic room temperature self-repairing elastomer of the present application;

[0031] Figure 5 DMA result diagram of the multiple dynamic room temperature self-repairing elastomer of the present application. DETAILED DESCRIPTION

[0032] The technical solutions of the present application are further described below in combination with the drawings, but the scope of protection claimed by the present application is not limited thereto.

[0033] Example 1

[0034] The present embodiment provides a preparation method of a multiple dynamic room temperature self-repairing elastomer (synthesis route refers to Figure 1 ), which specifically comprises the following steps:

[0035] Firstly, 1.74 g (15 mmol) of butanedione oxime, 3.33 g (15 mmol) of isophorone diisocyanate and 100 μL of dibutyltin dilaurate are added into a three-necked flask, 5 mL of N,N-dimethylformamide is added as a solvent, the three-necked flask is placed in an 80°C oil bath for 3 h, and the three-necked flask is protected by nitrogen gas throughout the process.

[0036] Secondly, 10 g of polytetrahydrofuran (Mn = ~ 1000 g / moL) dried at 120°C for 2 h and 5 mL of N,N-dimethylformamide are added into the above-mentioned prepolymer, and then the reaction system is kept at 80°C for continuous reaction for 3 h.

[0037] Thirdly, 2.22 g (10 mmol) of isophorone diisocyanate is added into a three-necked flask, the reaction system is kept at 60°C for continuous reaction for 12 h, and the obtained viscous product is poured into a polytetrafluoroethylene mold and dried in a vacuum oven at 80°C for 48 h. The polyurethane elastomer is obtained.

[0038] The infrared spectrum of the obtained elastomer is analyzed by infrared spectrum analysis as shown in Figure 2 1752 cm -1 is the C=O stretching vibration peak, 1519 cm -1 is the C-N stretching vibration peak, and 1104 cm -1 is the stretching vibration peak of urethane C-O-C. It can be obtained from the infrared characterization diagram that the polyurethane elastomer is successfully synthesized.

[0039] The obtained sample was cut into standard dumbbell samples, tensile test was carried out on a universal testing machine, and compared with two comparative examples, it was found that the tensile strength of the polyurethane elastomer prepared here reached 26.8 MPa, which was greater than that of the two comparative examples. Figure 3

[0040] The obtained elastomer was cut and spliced, and tensile test was carried out after repair at room temperature (25±5℃) for 12h, and the results are shown in Figure 4 As shown in the figure, during the cutting process, the polymer molecular chain was damaged, so the mechanical properties were difficult to recover to the initial sample, but the tensile strength recovered to 15.4 MPa, reaching 57.5% of the initial sample.

[0041] The obtained elastomer was subjected to DMA test, and the results are shown in Figure 5 As shown in the figure, the damping factor was greater than 0.3 in the range of 6-80℃, and the damping performance was good.

[0042] Example 2

[0043] The embodiment provides a preparation method of a multiple dynamic room temperature self-repairing elastomer, which specifically comprises the following steps:

[0044] Firstly, 1.16 g (10 mmol) of butanedione oxime, 2.22 g (10 mmol) of isophorone diisocyanate and 100 μL of dibutyltin dilaurate were added into a three-necked flask, 5 mL of N,N-dimethylformamide was added as a solvent, the three-necked flask was placed in an 80℃ oil bath for 3h, and the three-necked flask was protected by nitrogen gas as an atmosphere.

[0045] Secondly, 10 g of polytetrahydrofuran (Mn = ~ 1000 g / moL) dried at 120℃ for 2h and 5 mL of N,N-dimethylformamide were added into the above-mentioned prepolymer, and then the reaction system was kept at 80℃ for continuous reaction for 3h.

[0046] Thirdly, 2.22 g (10 mmol) of isophorone diisocyanate was added into a three-necked flask, the reaction system was kept at 60℃ for continuous reaction for 12h, and the obtained viscous product was poured into a polytetrafluoroethylene mold and dried in a 80℃ vacuum oven for 48h.

[0047] Comparative Example 1

[0048] A preparation method of a room temperature self-repairing polyurethane, comprising the following steps:

[0049] ​First step, 10 g of polytetrahydrofuran (Mn = ~ 1000 g / moL) vacuum dried at 120 °C for 2 h, 2.22 g (10 mmoL) of isophorone diisocyanate and 100 μL of dibutyltin dilaurate were added to a three-necked flask, 5 mL of N,N-dimethylformamide was added as solvent, the three-necked flask was placed in an 80 °C oil bath for 3 h, and the three-necked flask was protected by nitrogen gas throughout the process.

[0050] Second step, 1.16 g (10 mmoL) of butanedione oxime and 10 mL of N,N-dimethylformamide were added to a three-necked flask, the reaction system was kept at 60 °C and continued to react for 12 h, the obtained viscous product was poured into a polytetrafluoroethylene mold and dried in a vacuum oven at 80 °C for 48 h.

[0051] Comparative example 2

[0052] A method for preparing a room temperature self-healing polyurethane, comprising the following steps:

[0053] First step, 10 g of polytetrahydrofuran (Mn = ~ 1000 g / moL) vacuum dried at 120 °C for 2 h, 5.55 g (10 mmoL) of isophorone diisocyanate and 100 μL of dibutyltin dilaurate were added to a three-necked flask, 5 mL of N,N-dimethylformamide was added as solvent, the three-necked flask was placed in an 80 °C oil bath for 3 h, and the three-necked flask was protected by nitrogen gas throughout the process.

[0054] Second step, 1.74 g (15 mmoL) of butanedione oxime and 10 mL of N,N-dimethylformamide were added to a three-necked flask, the reaction system was kept at 60 °C and continued to react for 12 h, the obtained viscous product was poured into a polytetrafluoroethylene mold and dried in a vacuum oven at 80 °C for 48 h.

[0055] Obviously, the above examples are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can also be made by those skilled in the art. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations extending from the spirit of the present application are still within the protection scope of the present application.

Claims

1. A multi-functional dynamic room temperature self-healing polyurethane elastomer, characterized in that: The raw materials for this polyurethane elastomer include polyols, diisocyanates, dioxime chain extenders, catalysts, and solvents; Based on the total mass of the raw materials for this polyurethane elastomer being 100%, the percentage content of each component is as follows: Polyols 40%-70%; Diisocyanate 15%-40%; Dioxime chain extender 10%-30%; Catalyst 0.1%-0.3%; The ratio of solvent to polyol is 10-30 mL: 15 g; The polyol is a polyester polyol or a polyether polyol; The polyester polyol is at least one of polycaprolactone diol, polycarbonate diol, polyhexyl adipate diol, and polypropylene adipate diol, and the molecular weight of the polyester polyol is 600-9000. The polyether polyol is at least one of polytetrahydrofuran diol, polyethylene glycol, and polypropylene glycol, and the molecular weight of the polyether polyol is 600-9000. The diisocyanate is at least one selected from isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and diphenylmethane diisocyanate; The dioxime chain extender is at least one selected from dimethylglyoxime, 2,4-pentanedioxime, acetone aldehyde dioxime, 1,4-benzoquinone dioxime, dichloroglyoxime, and diphenylglyoxime. The catalyst is at least one of dibutyltin dilaurate, stannous isooctanoate, polyethyleneimine, and ethylenediamine. The solvent is at least one selected from N,N-dimethylformamide, N,N-dimethylacetamide, toluene, xylene, dimethyl sulfoxide, and tetrahydrofuran; The preparation method of this multi-dynamic room temperature self-healing polyurethane elastomer includes the following steps: Step 1: After mixing the dioxime chain extender, part of the diisocyanate, part of the solvent and catalyst evenly, heat at 60~80℃ for 1~6 h under an inert gas atmosphere, with a stirring speed of 100-400 r / min, to obtain the isocyanate-terminated prepolymer. Step 2: After dehydrating the polyol under vacuum at 100-150℃ for 2-6 h, add it to the isocyanate-terminated prepolymer obtained in Step 1, and heat at 60-80℃ for 1-6 h to obtain the polyurethane dynamic soft segment. Step 3: Add the remaining diisocyanate and solvent to the polyurethane dynamic soft segment obtained in Step 2, and then heat at 60~80℃ for 3~24 h with a stirring speed of 100-400 r / min to obtain a viscous liquid product. Step four: The viscous liquid product obtained in step three is heated and dried in a vacuum oven at a temperature of 60-100℃ for 24-72 hours to obtain a multi-dynamic room temperature self-healing polyurethane elastomer.

2. The multi-functional dynamic room temperature self-healing polyurethane elastomer according to claim 1, characterized in that: In step one, the mass of the added diisocyanate is 7.5%-30% of the total mass of the diisocyanate; the added solvent is half the total mass of the solvent.

3. An application of a multi-dynamic room temperature self-healing polyurethane elastomer, characterized in that: The multi-dynamic room temperature self-healing polyurethane elastomer described in claim 1 or 2 can be applied to the aerospace or transportation fields.

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