Multi-dynamic room-temperature self-repairing polyurethane elastomer and preparation method thereof

Abstract

The invention relates to a multi-dynamic room-temperature self-repairing polyurethane elastomer and a preparation method thereof, and belongs to the field of polyurethane materials, and the multi-dynamic room-temperature self-repairing polyurethane elastomer has high tensile strength of 26.8 MPa on the basis of self-repairing at room temperature. The material can realize efficient self-repairing under a mild room temperature condition, and the tensile strength of the material can be recovered to 15.4 MPa. In addition, the damping performance of the polyurethane elastomer material is excellent, and the damping factor is larger than 0.3 in the temperature range close to 80 DEG C. Ketoxime-urethane dynamic chemical bonds which are dynamically reversible at room temperature are introduced into polyol, so that the polyurethane material is endowed with room-temperature self-repairing capability; and the multi-dynamic chemical structure increases friction in a polyurethane molecular chain, promotes phase separation, and improves the damping performance of the material while improving the mechanical property.

Description

Technical Field

[0001] The invention relates to a high-strength, self-repairing multi-dynamic polyurethane elastomer and a preparation method thereof, belonging to the field of polyurethane materials. The polyurethane elastomer has high mechanical strength on the basis of being able to self-repair at room temperature. Background Art

[0002] Polyurethane is widely used in various industrial and consumer fields such as vibration reduction, noise reduction, smart sensors 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 to achieve different forms such as hard, soft and elastomer. As people's requirements for the quality of use become higher and higher, the self-healing ability of materials has received more and more attention. However, the improvement of mechanical properties of materials and the enhancement of self-healing properties are always an irreconcilable contradiction. At present, the main methods to improve the self-healing properties of polyurethane elastomer materials include adding repair microcapsules and introducing dynamic covalent bonds. After the material is damaged, the repair microcapsules will release repair substances to repair it quickly. However, the limited number of healing times will affect the long-term use of the material, and the presence of capsules will significantly reduce the mechanical properties of the material. After the material is damaged, the dynamic covalent material can be given self-healing properties by restoring dynamic reversible chemical bonds. However, the occurrence of this self-healing usually requires the input of light, heat, pressure or other external conditions, which limits its application scenarios.

[0003] In recent years, polyurethanes with self-healing functions have been widely studied. For example, Wei et al. introduced DA bonds into polyurethane elastomers through molecular chain design to achieve self-healing properties. The results showed that at 80°C, the self-healing rate of polyurethane elastomers with DA bonds was 67.56% (Wei YY, Ma XY. The self-healing cross-linked polyurethane by Diels-Alder polymerization. Advances in Polymer Technology, 2018, 37 (6): 1987). Song et al. prepared supramolecular polyurethane elastomers by dynamic covalent borate bonds and boric acid nitrogen coordination. Boron and nitrogen ligands promote the formation and dissociation of borate bonds at room temperature, while giving the material self-healing properties and enhancing the mechanical properties of the material. The tensile strength of the prepared sample reached 10.5MPa, and the strength could reach 5.2MPa after 24h of self-healing (Song K, Ye WJ, Gao XC, Fang HG, Zhang YQ, Zhang Q, Li XL, Yang SZ, Wei HB, Ding Y S. Synergy between dynamic covalent boronic ester and boron-nitrogen coordination: strategy for self-healing polyurethane elastomers at roomtemperature with unprecedented mechanical properties. Materials Horizons, 2021, 8(1): 216.). Both of the above polyurethanes have certain self-healing properties, but the difficulty of self-healing at room temperature and the low mechanical strength limit their further application. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a room temperature self-healing polyurethane material to overcome the problem that the polyurethane material in the prior art cannot have both good mechanical properties and room temperature self-healing properties.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A multi-dynamic room temperature self-repairing polyurethane elastomer, the raw materials of which include polyol, diisocyanate, dioxime chain extender, catalyst and solvent;

[0007] Wherein, the polyol is a polyester polyol or a polyether polyol;

[0008] Taking the total mass of the raw materials of the polyurethane elastomer as 100%, the percentage content of each component is:

[0009] Polyol 40%-70%;

[0010] Diisocyanate 15%-40%;

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

[0012] Catalyst 0.1%-0.3%;

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

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

[0015] 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;

[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 diacetyl oxime, 2,4-pentanedioxime, acetone aldehyde dioxime, 1,4-benzoquinone dioxime, dichloroglyoxime, and diphenylglyoxime;

[0018] The catalyst is at least one of dibutyltin dilaurate, stannous isooctanoate, 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 method for preparing a multi-dynamic room temperature self-repairing polyurethane elastomer, by introducing a dioxime chain extender into a polyol to make it have a dynamic chemical bond, thereby preparing a multi-dynamic high-strength room temperature self-repairing polyurethane; specifically comprising:

[0021] Step 1: After the dioxime chain extender, 7.5%-30% of the total mass of diisocyanate, half of the total solvent and the catalyst are mixed evenly, the mixture is heated at 60-80° C. for 1-6 hours under the protection of an inert gas (argon, nitrogen) atmosphere, and the stirring speed is 100-400 r / min to obtain an isocyanate-terminated prepolymer;

[0022] Step 2, adding the polyol to the isocyanate-terminated prepolymer obtained in step 1 after removing water at 100-150° C. under vacuum conditions for 2-6 hours, and heating at 60-80° C. for 1-6 hours to obtain a polyurethane dynamic soft segment;

[0023] Step 3, adding the remaining diisocyanate and solvent to the polyurethane dynamic soft segment obtained in step 2, and then heating at 60-80° C. for 3-24 hours with a stirring speed of 100-400 r / min to obtain a viscous liquid product;

[0024] Step 4: Heat and dry the viscous liquid product obtained in step 3 in a vacuum oven at a drying temperature of 60-100° C. for 24-72 hours to obtain a multi-dynamic room temperature self-healing polyurethane elastomer.

[0025] The obtained multi-dynamic room temperature self-healing polyurethane elastomer has vibration and noise reduction properties and can be used in aerospace or transportation fields.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: Overcoming the bottleneck of the prior art that the room temperature self-repairing performance and mechanical properties of polyurethane cannot be combined, a multiple dynamic room temperature self-repairing polyurethane elastomer and a preparation method thereof are proposed. A dynamically reversible ketoxime-urethane dynamic chemical bond at room temperature is introduced into the soft segment, thereby giving the polyurethane material room temperature self-repairing ability. The multiple dynamic chemical structure increases the friction within the polyurethane molecular chain, promotes phase separation, improves the mechanical properties, and improves the damping performance of the material. The damping factor is greater than 0.3 in the range of 6-80°C, and can be used for vibration reduction and noise reduction. The present invention relates to a multiple dynamic room temperature self-repairing polyurethane elastomer and a preparation method thereof, which belongs to the field of polyurethane materials. It can achieve high tensile strength of 26.8MPa on the basis of being able to self-repair at room temperature. The material can achieve efficient self-repair under mild room temperature conditions, and its 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 close to 80°C. By introducing the dynamic reversible ketoxime-urethane dynamic chemical bond at room temperature into the soft segment, the polyurethane material is endowed with room temperature self-healing ability; and this multiple dynamic chemical structure increases the friction within the polyurethane molecular chain, promotes phase separation, improves the mechanical properties and improves the damping performance of the material. The prepared high-strength multiple dynamic room temperature self-healing polyurethane elastomer has vibration reduction and noise reduction performance, can be used in the aerospace or transportation fields, and has good market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The synthetic route of the multi-dynamic room temperature self-healing polyurethane elastomer of the present invention;

[0028] Figure 2 This is the infrared spectrum of the multi-dynamic room temperature self-healing elastomer of the present invention;

[0029] Figure 3 Tensile strength diagram of the multi-dynamic room temperature self-healing elastomer of the present invention and the comparative example;

[0030] Figure 4 This is a room temperature self-healing result diagram of the multi-dynamic room temperature self-healing elastomer of the present invention;

[0031] Figure 5 This is the DMA result diagram of the multi-dynamic room temperature self-healing elastomer of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but the scope of protection claimed by the present invention is not limited thereto.

[0033] Example 1

[0034] This embodiment provides a method for preparing a multi-dynamic room temperature self-healing elastomer (synthetic route refers to Figure 1 ), specifically including the following steps:

[0035] In the first step, 1.74 g (15 mmoL) of dimethylglyoxime, 3.33 g (15 mmoL) of isophorone diisocyanate, and 100 μL of dibutyltin dilaurate were added into a three-necked flask, and then 5 mL of N,N-dimethylformamide was added as a solvent. The three-necked flask was placed in an 80°C oil bath for 3 hours, and nitrogen was introduced into the three-necked flask as a protective atmosphere throughout the process.

[0036] In the second step, 10 g of polytetrahydrofuran (Mn = 1000 g / moL) dried under vacuum at 120° C. for 2 h and 5 mL of N,N-dimethylformamide were added to the prepolymer, and then the reaction system was kept at 80° C. for 3 h.

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

[0038] The infrared spectrum of the obtained elastomer was analyzed by infrared spectroscopy. Figure 2 As shown, 1752cm -1 C=O stretching vibration peak, 1519cm -1 CN stretching vibration peak, 1104cm -1 It is the stretching vibration peak of carbamate COC. From the infrared characterization diagram, it can be seen that the polyurethane elastomer was successfully synthesized here.

[0039] The obtained samples were cut into standard dumbbell specimens, and tensile tests were performed on a universal testing machine. The results were compared with two comparative examples. Figure 3 It can be seen that the tensile strength of the polyurethane elastomer prepared here reaches 26.8MPa, which is greater than the two comparative examples.

[0040] The obtained elastomer was cut and then spliced, and a tensile test was performed after repairing at room temperature (25±5℃) for 12 hours. The results are as follows: Figure 4 As shown, during the cutting process, the polymer molecular chains were damaged, so the mechanical properties were difficult to recover to that of the initial sample, but its 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 as follows Figure 5 As shown, the damping factor is greater than 0.3 in the range of 6-80℃, which has good damping performance.

[0042] Example 2

[0043] This embodiment provides a method for preparing a multi-dynamic room temperature self-healing elastomer, which specifically includes the following steps:

[0044] In the first step, 1.16 g (10 mmoL) of dimethylglyoxime, 2.22 g (10 mmoL) of isophorone diisocyanate, and 100 μL of dibutyltin dilaurate were added into a three-necked flask, and then 5 mL of N,N-dimethylformamide was added as a solvent. The three-necked flask was placed in an 80°C oil bath for 3 hours, and nitrogen was introduced into the three-necked flask as a protective atmosphere throughout the process.

[0045] In the second step, 10 g of polytetrahydrofuran (Mn = 1000 g / moL) dried under vacuum at 120° C. for 2 h and 5 mL of N,N-dimethylformamide were added to the prepolymer, and then the reaction system was kept at 80° C. for 3 h.

[0046] In the third step, 2.22 g (10 mmol) of isophorone diisocyanate was added into a three-necked flask, and the reaction system was kept at 60° C. 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.

[0047] Comparative Example 1

[0048] A method for preparing room temperature self-repairing polyurethane comprises the following steps:

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

[0050] In the second step, 1.16 g (10 mmol) of dimethylglyoxime and 10 mL of N,N-dimethylformamide were added into a three-necked flask, and the reaction system was kept at 60° C. for 12 h. The 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 room temperature self-repairing polyurethane comprises the following steps:

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

[0054] In the second step, 1.74 g (15 mmol) of diacetyl oxime and 10 mL of N,N-dimethylformamide were added into a three-necked flask, and the reaction system was kept at 60° C. 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 embodiments are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, these obvious changes or modifications derived from the spirit of the present invention are still within the scope of protection of the present invention.

Claims

1. A multi-dynamic room temperature self-repairing polyurethane elastomer, characterized in that: The raw materials of the polyurethane elastomer include polyol, diisocyanate, dioxime chain extender, catalyst and solvent; Taking the total mass of the raw materials of the polyurethane elastomer as 100%, the percentage content of each component is: Polyol 40%-70%; Diisocyanate 15%-40%; Dioxime chain extender 10%-30%; Catalyst 0.1%-0.3%; The usage ratio of solvent to polyol is 10-30mL:15g.

2. The multi-dynamic room temperature self-repairing polyurethane elastomer according to claim 1, characterized in that: The polyol is polyester polyol or polyether polyol.

3. The multi-dynamic room temperature self-repairing polyurethane elastomer according to claim 1, characterized in that: The polyester polyol is at least one of polycaprolactone diol, polycarbonate diol, polyhexamethylene 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 polytetramethylene glycol, polyethylene glycol and polypropylene glycol, and the molecular weight of the polyether polyol is 600-9000.

4. The multi-dynamic room temperature self-repairing polyurethane elastomer according to claim 1, characterized in that: The diisocyanate is at least one of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate and diphenylmethane diisocyanate.

5. The multi-dynamic room temperature self-repairing polyurethane elastomer according to claim 1, characterized in that: The dioxime chain extender is at least one of diacetyl oxime, 2,4-pentane dioxime, acetone aldehyde dioxime, 1,4-benzoquinone dioxime, dichloroglyoxime, and diphenylglyoxime.

6. The multi-dynamic room temperature self-repairing polyurethane elastomer according to claim 1, characterized in that: The catalyst is at least one of dibutyltin dilaurate, stannous isooctanoate, polyethyleneimine and ethylenediamine.

7. The multi-dynamic room temperature self-repairing polyurethane elastomer according to claim 1, characterized in that: The solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, toluene, xylene, dimethyl sulfoxide and tetrahydrofuran.

8. A method for preparing a multi-dynamic room temperature self-repairing polyurethane elastomer, characterized in that the steps include: Step 1: after the dioxime chain extender, part of the diisocyanate, part of the solvent and the catalyst are uniformly mixed, the mixture is heated at 60-80° C. for 1-6 hours under the protection of an inert gas atmosphere, and the stirring speed is 100-400 r / min to obtain an isocyanate-terminated prepolymer; Step 2, adding the polyol to the isocyanate-terminated prepolymer obtained in step 1 after removing water at 100-150° C. under vacuum conditions for 2-6 hours, and heating at 60-80° C. for 1-6 hours to obtain a polyurethane dynamic soft segment; Step 3, adding the remaining diisocyanate and solvent to the polyurethane dynamic soft segment obtained in step 2, and then heating at 60-80° C. for 3-24 hours with a stirring speed of 100-400 r / min to obtain a viscous liquid product; Step 4: Heat and dry the viscous liquid product obtained in step 3 in a vacuum oven at a drying temperature of 60-100° C. for 24-72 hours to obtain a multi-dynamic room temperature self-healing polyurethane elastomer.

9. The method for preparing a multi-dynamic room temperature self-repairing polyurethane elastomer according to claim 8, characterized in that: In the step 1, the mass of the added diisocyanate is 7.5%-30% of the total mass of the diisocyanate; and the added solvent is half of the total mass of the solvent.

10. An application of a multi-dynamic room temperature self-repairing polyurethane elastomer, characterized in that: Multiple dynamic room temperature self-healing polyurethane elastomers are used in aerospace or transportation fields.

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