A high-damping bio-based polyurethane composite material capable of self-repair at room temperature and a preparation method thereof

Abstract

The present invention discloses a high-damping bio-based polyurethane composite material capable of self-repairing at room temperature and a preparation method thereof. The invention belongs to the field of damping material technology. The high-damping bio-based polyurethane composite material capable of self-repairing at room temperature comprises the following raw materials: a flavonoid compound, phenylenediboronic acid, an oligomeric diol, a diisocyanate, a small molecule disulfide chain extender, and a catalyst. The high-damping bio-based polyurethane composite material capable of self-repairing at room temperature has a breaking strength of 0.04-3 MPa, an elongation at break of 1000-1400%, a glass transition temperature of 130-150°C, a loss factor between 0.65-1.7, and a room-temperature recovery efficiency of over 95%. The composite material has excellent damping and recovery performance, can replace traditional damping materials, reduces the consumption of petrochemical raw materials, and meets the needs of sustainable development.

Description

Technical Field

[0001] The present invention belongs to the technical field of damping materials, and in particular relates to a high-damping bio-based polyurethane composite material capable of self-repairing at room temperature and a preparation method thereof. Background Art

[0002] With the rapid development of modern manufacturing, vibration and noise issues are becoming increasingly prominent. On the one hand, they affect the accuracy, reliability, and service life of instruments, equipment, and weaponry; on the other hand, they endanger human health and increase the risk of disease. Therefore, vibration and noise reduction are urgent. Damping materials can absorb the vibration energy of loaded mechanical components and irreversibly convert it into heat energy for dissipation, thereby achieving the purpose of vibration and noise reduction. This energy conversion and dissipation is the damping effect. The magnitude of the damping effect can be characterized by the material's dynamic mechanical properties, including the storage modulus and loss factor. The larger the loss factor (tanδ ≥ 0.3), the better the damping effect.

[0003] With the rapid development of industry, conventional fossil fuels face two challenges. First, conventional fossil fuels are non-renewable energy sources. As demand continues to grow, their extraction costs continue to rise and reserves are gradually depleting. Second, there are environmental concerns. Pollutants produced by burning fossil fuels can contribute to global warming and the greenhouse effect. The gradual depletion of conventional fossil fuels and their environmental impact make the development of bio-based renewable materials of great significance.

[0004] Polyurethane (PU) materials offer advantages such as excellent wear resistance, strong shock absorption, and high molecular controllability. The damping factor of PU damping materials can be enhanced by adjusting the type and ratio of soft and hard segments. Therefore, PU damping materials have become a highly researchable and practical damping material. However, currently available PU damping materials lack both recyclability and high damping performance. Therefore, a recyclable PU damping material with high damping performance must be designed to meet the growing demand for damping materials.

[0005] Flavonoids are widely used bio-based and biodegradable raw materials. They are natural plant extracts with a broad and renewable source, and can effectively alleviate environmental and energy crises. Among them, flavonoids with an o-triphenolic hydroxyl structure possess greater structural rigidity and a higher number of hydroxyl groups. Using flavonoids with o-triphenolic hydroxyl structures as hard segments in polyurethanes, replacing the non-degradable chain extenders and crosslinkers used in traditional polyurethane synthesis, can reduce petroleum consumption. Furthermore, the structural characteristics of these biomass compounds can be exploited to introduce two reversible covalent bonds (borate and disulfide bonds) into the polyurethane network, endowing it with the ability to rearrange its crosslinked network topology. Therefore, polyurethanes prepared using flavonoids with o-triphenolic hydroxyl structures have great potential for use as green damping materials. However, reports on this topic are limited, and further research is needed.

[0006] Patent CN117866168A discloses a bio-based self-healing high-strength and high-toughness polyurethane material and its preparation method. Flavonoid compounds are used in the preparation process. The prepared polyurethane material not only effectively improves its strength, toughness and thermal stability (strain exceeds 1638%, and the fracture strength is as high as 66MPa), but can also be recycled and repaired. However, its recycling efficiency after repair at 100°C is too low, it cannot be recycled at room temperature, and its damping performance is relatively poor. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-damping bio-based polyurethane composite material that can self-repair at room temperature and a preparation method thereof, so as to solve the problems of low loss factor, non-renewable raw materials and non-self-repairability of existing polyurethane damping materials. Existing bio-based polyurethane composite materials are difficult to meet the damping requirements under certain specific environments. In order to improve the damping performance of bio-based polyurethane composite materials, the present invention uses bio-based raw material flavonoid compounds as the hard segment of the material. By utilizing its structural rigidity and the high activity of hydroxyl groups in the structure, it can replace traditional petrochemical chain extenders and reduce oil consumption; it can also increase the friction of chain segment movement, giving the polyurethane damping material excellent damping performance. In addition, the small molecule disulfide chain extender added at the same time as the reaction of flavonoid compounds with phenyldiboronic acid can introduce dynamically reversible borate ester bonds and disulfide bonds into the polyurethane damping material, giving the polyurethane damping material self-repair and wide temperature range damping performance, thereby extending the material's service stability and life.

[0008] One of the technical solutions provided by the present invention:

[0009] A high-damping bio-based polyurethane composite material capable of self-repairing at room temperature comprises the following raw materials: a flavonoid compound, phenylenediboronic acid, an oligomeric diol, a diisocyanate, a small molecule disulfide chain extender, and a catalyst.

[0010] The oligomer diol constitutes the soft segment of the high-damping bio-based polyurethane composite material capable of self-repairing at room temperature, and the flavonoid compound, phenylenediboronic acid, diisocyanate and small molecule disulfide chain extender constitute the hard segment of the high-damping bio-based polyurethane composite material capable of self-repairing at room temperature.

[0011] In the synthesis of polyurethane damping materials, diisocyanate is a very important raw material, acting as a crosslinker in the reaction. Phenyldiboronic acid and the o-triphenolic hydroxyl groups in flavonoids can form dynamically reversible borate bonds. The rapid exchange of the triphenolic hydroxyl borate bonds can absorb impact energy and enhance the damping effect of the polyurethane. Simultaneously, the addition of a small molecule disulfide chain extender introduces dynamically reversible disulfide bonds into the polyurethane network. The small molecule disulfide chain extender has two functions: first, utilizing the low-temperature exchange capacity of the disulfide bonds to achieve room-temperature repair, and second, absorbing impact energy at low temperatures to enhance damping. Because the exchange temperature of borate is above 100°C, and the exchange temperature of the disulfide bonds can range from room temperature to 100°C, the combination of these two dynamic bonds in the temperature range enables wide-temperature damping of the polyurethane material, giving the prepared polyurethane damping material self-repairing capabilities and wide-temperature damping performance.

[0012] Preferably, the phenylenediboronic acid includes one or more of 2,2′-biphenylenediboronic acid, 1,3-phenylenediboronic acid and 1,4-phenylenediboronic acid.

[0013] Preferably, the small molecule disulfide chain extender includes one or more of 2,2′-dithiodiethyldiamine dihydrochloride and N,N′-(dithiodiylbis(ethane-2,1-diyl))diacrylamide.

[0014] Preferably, the flavonoid compound is a flavonoid compound containing an o-triphenolic hydroxyl structure, and the flavonoid compound is selected from dihydromyricetin or baicalin, preferably dihydromyricetin.

[0015] The hard segment raw materials of the high-damping bio-based polyurethane composite material that can self-repair at room temperature provided by the present invention are flavonoid compounds, which are abundant in reserves, inexpensive, have multiple highly active functional groups, and have the dual characteristics of recycling and biodegradation. This allows them to re-enter the production link through recycling processes after being discarded, and can also be decomposed by microorganisms in the natural environment, thereby reducing the long-term impact on the environment.

[0016] The oligomer diol includes one or more of hydroxy-terminated polybutadiene, polytetramethylene glycol, polyether glycol 220 and polyhexamethylene adipate diol.

[0017] The diisocyanate includes one or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate and dicyclohexylmethane diisocyanate.

[0018] The catalyst includes one or more of dibutyltin dilaurate, stannous octoate or stannous chloride.

[0019] The second technical solution provided by the present invention is:

[0020] A method for preparing the above-mentioned high-damping bio-based polyurethane composite material that can self-repair at room temperature comprises the following steps: S1. dissolving a flavonoid compound and phenyldiboronic acid in a dry solvent, heating the mixture for reaction, and synthesizing a polymer A; S2. introducing nitrogen into the heated oligomer diol, stirring the mixture, replenishing the solvent, and cooling the mixture at the same time, then adding a diisocyanate and a catalyst, heating the mixture and introducing nitrogen for reaction, then adding a small molecule disulfide chain extender, continuing the reaction, and finally adding the polymer A to obtain a prepolymer after the reaction; S3. removing the solvent of the prepolymer, molding the prepolymer, and obtaining the high-damping bio-based polyurethane composite material that can self-repair at room temperature.

[0021] The invention removes the solvent in an oven by casting a film, and performs extrusion, hot pressing and other processes on the polymer after the solvent is removed according to specific circumstances to shape the material, thereby obtaining a high-damping bio-based polyurethane composite material that can self-repair at room temperature.

[0022] The solvent is tetrahydrofuran, dichloromethane, acetone, dimethyl sulfoxide or N-methylpyrrolidone.

[0023] Preferably, the molar ratio of the flavonoid compound to the phenyldiboronic acid in S1 is 5:2, and the temperature of the heating reaction in S1 is 60-80° C. and the time is 12-36 hours.

[0024] Preferably, the molar ratio of the small molecule disulfide chain extender in S2 to the polymer A is (0.5-2.5):1, the molar ratio of the oligomer diol in S2 to the diisocyanate is (1-3.5):1, the molar ratio of the oligomer diol in S2 to the polymer A is (5-8):1, the heating temperature of the oligomer diol in S2 is 100°C, and the cooling is to reduce the temperature to 60°C.

[0025] The present invention replaces the non-degradable chain extenders and crosslinkers used in traditional polyurethane synthesis with flavonoid compounds and cystamine (a structure found in small molecule disulfide chain extenders) having an o-triphenolic hydroxyl structure. Simultaneously, by utilizing the structural characteristics of these biomass compounds, two reversible covalent bonds (borate and disulfide bonds) are introduced into the polyurethane network, enabling the crosslinked network to have the ability to rearrange its topology, thus endowing the polyurethane composite with room temperature self-repair and recycling properties, thereby extending the material's service stability and lifespan. After mechanical damage occurs, the high-damping bio-based polyurethane composite material capable of self-repair at room temperature can be joined and self-repaired at room temperature. The polyurethane composite material is crushed and placed in a flat-plate vulcanizer. The polymer powder is pressurized and molded at room temperature and under a pressure of 10-15 MPa for 2-3 hours to produce a block material with a tensile strength similar to that of the original sample, thereby enabling the recycling and reuse of the above-mentioned material.

[0026] The present invention uses flavonoid compounds as the hard segment of the material. Utilizing the structural characteristics of flavonoid compounds with multiple benzene rings, the presence of π-π interactions between the benzene rings, and the high activity of the hydroxyl groups in the structure, it can not only replace traditional petrochemical chain extenders and reduce oil consumption, but also increase the friction of the chain segment movement, so that the material produces a greater damping effect when subjected to stress. In addition, the damping effect of the polyurethane composite material provided by the present invention is not only derived from the controlled ratio of soft and hard segments in the polyurethane, but also from the borate ester bond formed by o-triphenolic hydroxyl groups and phenylboronic acid. In this system, the introduction of dynamic borate ester bonds does not serve as a repair unit, but mainly utilizes the rapid exchange of triphenolic hydroxyl borate ester bonds to absorb impact energy and enhance the damping effect of the polyurethane. At the same time, the present invention incorporates disulfide bond small molecules as chain extenders for two purposes: first, to achieve room temperature repair by utilizing the low-temperature exchange ability of disulfide bonds; second, to absorb impact energy at low temperatures and enhance damping. Because the exchange temperature of borate esters is above 100°C, the exchange temperature of disulfide bonds can range from room temperature to 100°C. The combination of these two dynamic bonds in the temperature range achieves wide-temperature damping of the polyurethane material. In summary, the biomass dihydromyricetin and baicalin of the present invention replace traditional petrochemical products. At the same time, their special structure enables the polyurethane network to have borate bonds and π-π effects, combined with disulfide dynamic bonds, and the three effects work together to improve the damping of the material.

[0027] Compared with the existing technology, the invention has the following advantages and technical effects:

[0028] Generally speaking, damping materials cannot have both raw material regeneration and damping performance, and do not have self-repair functions. However, the high-damping bio-based polyurethane composite material that can self-repair at room temperature of the present invention has good damping performance and excellent self-repair and recycling functions. Not only does it maintain good damping performance (tanδ>1.6) when using renewable biomass as a raw material, it can also be recycled and repaired. When crack damage occurs in the bio-based polyurethane composite material of the present invention, it only needs to be pressurized to restore it to its original state, and surface bonding and connection can be achieved without the use of any external adhesive. The polyurethane composite material prepared from bio-based raw materials of the present invention can replace traditional damping materials, reduce the consumption of petrochemical raw materials, and reduce the generation of waste materials, which meets the needs of sustainable development.

[0029] The room-temperature self-repairable high-damping bio-based polyurethane composite material of the present invention has a breaking strength of 0.04-3 MPa, an elongation at break of 1000-1400%, a glass transition temperature of 130-150°C, a loss factor between 0.65-1.7, and a room-temperature recycling efficiency of more than 95%. It has excellent damping performance and recycling and repair performance, can replace traditional damping materials, reduce the consumption of petrochemical raw materials, and meet the needs of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 The stress-strain curves of the room-temperature self-repairing high-damping bio-based polyurethane composites prepared in Examples 1-3;

[0032] Figure 2 The stress-strain curve of the room temperature self-repairable high-damping bio-based polyurethane composite material prepared in Example 1-3 after room temperature repair;

[0033] Figure 3 The loss factor diagram of the room temperature self-repairable high-damping bio-based polyurethane composite material prepared in Examples 1-3 during temperature scanning;

[0034] Figure 4 Activation energy diagram of the room temperature self-repairable high-damping bio-based polyurethane composite material prepared in Examples 1-3;

[0035] Figure 5 The stress-strain curves of the room-temperature self-repairing bio-based polyurethane composite material prepared in Comparative Example 1 and the polyurethane composite material after room-temperature self-repairing;

[0036] Figure 6 Graphs of loss factors during temperature scans of the room-temperature self-repairable bio-based polyurethane composite materials prepared in Comparative Example 1 and Examples 1 and 3;

[0037] Figure 7 The stress-strain curves of the bio-based self-healing high-strength and high-toughness polyurethane material (initial) and the polyurethane material (after repair at 100°C) prepared in Comparative Example 2;

[0038] Figure 8 This is a sample photo of the bio-based self-healing high-strength and high-toughness polyurethane material prepared in Comparative Example 2 after room temperature repair.

[0039] Figure 9 The loss factor diagrams during temperature scanning of the bio-based self-repairing high-strength and high-toughness polyurethane material prepared in Comparative Example 2 and the high-damping bio-based polyurethane composite materials capable of self-repairing at room temperature prepared in Examples 1 and 3;

[0040] Figure 10 The stress-strain curves of the self-repairable bio-based polyurethane composite material (initial) and the polyurethane composite material (after repair at 100°C) prepared in Comparative Example 3;

[0041] Figure 11 This is a sample photo of the self-repairable bio-based polyurethane composite material prepared in Comparative Example 3 after room temperature repair.

[0042] Figure 12 Graph showing the loss factor during temperature scanning of the self-healing bio-based polyurethane composites prepared in Comparative Example 3 and Examples 1 and 3. DETAILED DESCRIPTION

[0043] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0044] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0045] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0046] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the present invention. The present description and examples are intended to be illustrative only.

[0047] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0048] The room temperature in the present invention refers to 25±2°C.

[0049] The raw materials used in the examples of the present invention were all purchased from commercial sources, wherein the hydroxy-terminated polybutadiene was purchased from Anaiji Chemical, and its molar mass was 3800.

[0050] Example 1

[0051] (1) Weigh dihydromyricetin (6.40 g, 20 mmol) and 1,4-phenylenediboronic acid (1.328 g, 8 mmol) and place them in a 100 mL three-necked flask. Add 50 mL of dry tetrahydrofuran and react at 60°C for 12 h. During the reaction, pay attention to the amount of solvent and replenish the solvent in time. The synthesized polymer is polymer A.

[0052] (2) Synthesis of prepolymer: 26.6 g of hydroxy-terminated polybutadiene (7 mmol) was placed in a 250 mL three-necked flask, stirred at 100 ° C for 2 h, and then 80 mL of tetrahydrofuran was added as solvent, and the temperature was lowered to 60 ° C. Then, isophorone diisocyanate (1.467 g, 6.6 mmol) and 7 drops of catalyst (dibutyltin dilaurate) were added, and nitrogen was introduced and reacted (60 ° C, 40 min). Then, a small molecule disulfide chain extender (2,2′-dithiodiethylamine dihydrochloride) (0.137 g, 0.9 mmol) was added and reacted (60 ° C, 0.5 h). Finally, polymer A (0.3316 g, 1.35 mmol) of step (1) was added and reacted (60 ° C, 1 h) to obtain a prepolymer;

[0053] (3) Molding: The prepolymer of step (2) was transferred to a 250 mL round-bottom flask, 1 / 2 of the solvent was evaporated at room temperature, and then introduced into a polytetrafluoroethylene mold. It was first heated and cured in a 40°C oven, and the temperature was increased by 10°C every half a day. After two days, it was finally raised to 80°C. The solvent was removed to obtain a high-damping bio-based polyurethane composite material that can self-repair at room temperature. The high-damping bio-based polyurethane composite material that can self-repair at room temperature was cut into pieces and pressurized in a flat vulcanizer at room temperature (15 MPa, 2 h) to re-mold the material to obtain a repaired polyurethane composite material.

[0054] According to GB / T1040.1-2006, the room temperature self-repairable high-damping bio-based polyurethane composite material and the repaired polyurethane composite material were cut into dumbbell-shaped specimens, and tensile tests were performed at room temperature at a speed of 100 m / min. The stress-strain curve of the room temperature self-repairable high-damping bio-based polyurethane composite material (initial) of this embodiment is shown in FIG. Figure 1 The stress-strain curve of the repaired polyurethane composite material (after repair at room temperature) is shown in Figure 2 ,Depend on Figure 1 It can be seen that the initial stress is 2.64MPa and the strain is 1083%. Figure 2 It can be seen that after room temperature repair, the stress is 2.6 MPa, the strain is 613%, and the tensile strength self-repair ability is 98.5%.

[0055] The damping properties of the room temperature self-repairable high damping bio-based polyurethane composite material prepared in this embodiment are as follows: Figure 3As shown in Example 1, the loss factor is 0.66, the glass transition temperature Tg is 132°C, the temperature range is 160°C, and it has damping and vibration reduction performance at -10°C-150°C.

[0056] Example 2

[0057] (1) Weigh dihydromyricetin (6.40 g, 20 mmol) and 1,4-phenylenediboronic acid (1.328 g, 8 mmol) and place them in a 100 ml three-necked flask. Add 50 ml of dry tetrahydrofuran and react at 60 °C for 12 h. During the reaction, pay attention to the amount of solvent and replenish the solvent in time. The synthesized polymer is polymer A.

[0058] (2) Synthesis of prepolymer: Hydroxyl-terminated polybutadiene (34.19 g, 9 mmol) was weighed in a 250 mL three-necked flask, stirred at 100 °C for 2 h, and then 50 mL of tetrahydrofuran was added as solvent, and the temperature was lowered to 60 °C. Then, isophorone diisocyanate (1.467 g, 6.6 mmol) and 7 drops of catalyst (dibutyltin dilaurate) were added, nitrogen was introduced and reacted (60 °C, 40 min), and then a small molecule disulfide chain extender (2,2′-dithiodiethylamine dihydrochloride) (0.137 g, 0.9 mmol) was added and reacted (60 °C, 0.5 h), and finally, polymer A (0.3316 g, 1.35 mmol) of step (1) was added and reacted (60 °C, 1 h) to obtain a prepolymer;

[0059] (3) Molding: The prepolymer of step (2) was transferred to a 250 mL round-bottom flask, 1 / 2 of the solvent was evaporated at room temperature, and then introduced into a polytetrafluoroethylene mold. It was first heated and cured in a 40°C oven, and the temperature was increased by 10°C every half a day. After two days, it was finally raised to 80°C. The solvent was removed to obtain a high-damping bio-based polyurethane composite material that can self-repair at room temperature. The high-damping bio-based polyurethane composite material that can self-repair at room temperature was cut into pieces and pressurized in a flat vulcanizer at room temperature (10 MPa, 3 h) to re-mold the material to obtain a repaired polyurethane composite material.

[0060] According to GB / T1040.1-2006, the room temperature self-repairable high-damping bio-based polyurethane composite material and the repaired polyurethane composite material were cut into dumbbell-shaped specimens, and tensile tests were performed at room temperature at a speed of 100 m / min. The stress-strain curve of the room temperature self-repairable high-damping bio-based polyurethane composite material (initial) of this embodiment is shown in FIG. Figure 1 The stress-strain curve of the repaired polyurethane composite material (after repair at room temperature) is shown in Figure 2 ,Depend on Figure 1 It can be seen that the initial stress is 0.044MPa and the strain is 1334%. Figure 2It can be seen that after room temperature repair, the stress is 0.043 MPa, the strain is 1496%, and the tensile strength self-repair ability is 97.7%.

[0061] The damping properties of the room temperature self-repairable high damping bio-based polyurethane composite material prepared in this embodiment are as follows: Figure 3 As shown in Example 2, the loss factor is 1.29, the glass transition temperature Tg is 143°C, the temperature range is 178°C, and the material has damping and vibration reduction performance at -28°C-150°C.

[0062] Example 3

[0063] (1) Weigh dihydromyricetin (6.40 g, 20 mmol) and 1,4-phenylenediboronic acid (1.328 g, 8 mmol), place in a 100 mL three-necked flask, add 50 mL of tetrahydrofuran solvent, and react at 60 ° C for 12 h. During the reaction, pay attention to the amount of solvent and replenish the solvent in time. The synthesized polymer is polymer A;

[0064] (2) Synthesis of prepolymer: Hydroxyl-terminated polybutadiene (26.6 g, 7 mmol) was placed in a 250 mL three-necked flask and stirred at 100 °C for 2 h. Then, 50 mL of tetrahydrofuran was added as solvent and the temperature was lowered to 60 °C. Then, isophorone diisocyanate (1.467 g, 6.6 mmol) and 7 drops of catalyst (dibutyltin dilaurate) were added and nitrogen was introduced and reacted (60 °C, 50 min). Then, a small molecule disulfide chain extender (2,2′-dithiodiethylamine dihydrochloride) (0.175 g, 1.15 mmol) was added and reacted (60 °C, 0.5 h). Finally, polymer A (0.2702 g, 1.1 mmol) was added (60 °C, 1 h) to obtain a prepolymer.

[0065] (3) Molding: The prepolymer of step (2) was transferred to a 250 mL round-bottom flask, 1 / 2 of the solvent was evaporated at room temperature, and then introduced into a polytetrafluoroethylene mold. It was first heated and cured in a 40° C. oven, and the temperature was increased by 10° C. every half a day. After two days, it was finally raised to 80° C., and the solvent was removed to obtain a high-damping bio-based polyurethane composite material that can self-repair at room temperature. The high-damping bio-based polyurethane composite material that can self-repair at room temperature was cut into pieces and pressurized in a flat vulcanizer at room temperature (15 MPa, 3 h) to re-mold the material to obtain a repaired polyurethane composite material.

[0066] According to GB / T1040.1-2006, the room temperature self-repairable high-damping bio-based polyurethane composite material and the repaired polyurethane composite material were cut into dumbbell-shaped specimens, and tensile tests were performed at room temperature at a speed of 100 m / min. The stress-strain curve of the room temperature self-repairable high-damping bio-based polyurethane composite material (initial) of this embodiment is shown in FIG. Figure 1The stress-strain curve of the repaired polyurethane composite material (after repair at room temperature) is shown in Figure 2 ,Depend on Figure 1 It can be seen that the initial stress is 0.165MPa and the strain is 1112%. Figure 2 It can be seen that after room temperature repair, the stress is 0.164MPa, the strain is 539%, and the tensile strength self-repair ability is 99.4%.

[0067] The damping properties of the room temperature self-repairable high damping bio-based polyurethane composite material prepared in this embodiment are as follows: Figure 3 As shown in Example 3, the loss factor is 1.67, the glass transition temperature Tg is 147°C, the temperature range is 190°C, and it has damping and vibration reduction performance at -40°C-150°C.

[0068] As shown in the above examples, the room-temperature self-repairing, high-damping bio-based polyurethane composites prepared in Examples 1-3 all exhibit self-repairing capabilities, with stress recovery exceeding 95% after repair. Examples 2 and 3 both exhibited loss factors greater than 1 across a wide temperature range, demonstrating excellent damping performance. In contrast, Example 1 exhibited a loss factor of only 0.66, a relatively narrow temperature range, and relatively poor damping performance.

[0069] Figure 4 Activation energy diagram of high damping bio-based polyurethane composite material capable of self-repair at room temperature prepared in Examples 1-3; Figure 4 It can be seen that the activation energy of the polyurethane damping material prepared in Example 3 is the lowest among Examples 1-3, indicating that Example 3 requires lower conditions for self-repair and is easier to self-repair. The activation energy calculation method is: Ea = slope * 8.314.

[0070] Comparative Example 1

[0071] Same as Example 3, except that dihydromyricetin in step (1) is replaced by quercetin.

[0072] According to GB / T1040.1-2006, the room temperature self-repairable bio-based polyurethane composite material of Comparative Example 1 and the repaired polyurethane composite material were cut into dumbbell-shaped specimens, and tensile tests were performed at room temperature at a speed of 100 m / min. The stress-strain curves of the room temperature self-repairable bio-based polyurethane composite material of Comparative Example 1 (initial) and the stress-strain curves of the repaired polyurethane composite material (after room temperature repair) are shown in FIG. Figure 5 .Depend on Figure 5 It can be seen that the initial stress of Comparative Example 1 is 2.08 MPa, the strain is 645%, the stress after room temperature repair is 1.71 MPa, the strain is 316%, and the tensile strength self-repair ability is 82.2%.

[0073] The damping performance of the room temperature self-repairable bio-based polyurethane composite material of Comparative Example 1 is as follows: Figure 6 As shown in Comparative Example 1, the loss factor of Comparative Example 1 is 0.46, the glass transition temperature Tg is 133°C, the temperature range is 100°C, and it has damping and shock absorption performance at 50°C-150°C. The reason for the performance degradation is that the structure of dihydromyricetin is o-triphenolic hydroxyl group, while the structure of quercetin is o-diphenolic hydroxyl group, so the number of borate ester bonds and disulfide bonds formed is affected, and the friction movement of the chain segments is relatively reduced, thereby affecting the self-healing ability and damping performance of the material.

[0074] Comparative Example 2

[0075] The bio-based self-repairing high-strength and high-toughness polyurethane material prepared in Example 2 of patent CN117866168 A.

[0076] According to GB / T 1040.1-2006, the stress-strain curves of the bio-based self-repairing high-strength and high-toughness polyurethane material (initial) and the repaired polyurethane elastomer material (after repair at 100°C) prepared in Comparative Example 2 are shown in Figure 7 ,Depend on Figure 7 It can be seen that the initial stress is 66.0MPa and the strain is 1638%; after repair at 100℃, the stress is 52.5MPa, the strain is 1755%, and the tensile strength self-repair ability is 79.5%. Figure 8 ,Depend on Figure 8 It can be seen that it cannot be formed under pressure at room temperature and cannot self-repair. Compared with the present invention, the bio-based self-repairing high-strength and high-toughness polyurethane material prepared in Comparative Example 2 requires more conditions for self-repair and can only be self-repaired at temperatures above 100°C, and the self-repair effect is poor. Because only borate bonds are formed as repair units in the reaction, and dynamic borate covalent bonds require a higher temperature above 100°C or the presence of water molecules to undergo a dynamic reversible break-recombination process, the cross-linked polyurethane material is difficult to self-repair or recycle at room temperature.

[0077] The damping performance of the bio-based self-repairing high-strength and high-toughness polyurethane material of Comparative Example 2 is as follows: Figure 9 As shown in Comparative Example 2, the loss factor of Comparative Example 2 is 0.38, the glass transition temperature Tg is 130°C, the temperature range is 50°C, and it has damping and shock absorption performance at 100°C-150°C. Compared with the present invention, its damping performance is not very good, and the damping temperature range is narrow.

[0078] Comparative Example 3

[0079] Same as Example 3, except that the small molecule disulfide chain extender in step (2) is removed.

[0080] According to GB / T1040.1-2006, the self-repairable bio-based polyurethane composite material of Comparative Example 3 and the repaired polyurethane composite material were cut into dumbbell-shaped specimens, and tensile tests were performed at room temperature at a speed of 100 m / min. The stress-strain curves of the self-repairable bio-based polyurethane composite material of Comparative Example 3 (initial) and the stress-strain curves of the repaired polyurethane composite material (after repair at 100°C) are shown in FIG. Figure 10 .Depend on Figure 10 It can be seen that the initial stress of comparative example 3 is 8.65MPa, the strain is 1185%, the stress after repair at 100℃ is 5.04MPa, the strain is 968%, and the self-repairing ability of tensile strength is 58.3%. Figure 11 ,Depend on Figure 11 It can be seen that it cannot be molded under pressure at room temperature and cannot self-repair. The reason for the reduced repair ability is that without the addition of a small molecule disulfide chain extender, only dynamic borate bonds are formed, and disulfide bonds with low-temperature exchange ability cannot be formed. Therefore, self-repair cannot be carried out at room temperature, and can only be carried out at high temperatures above 100°C, and the repair effect is not ideal.

[0081] The damping performance of the self-repairable bio-based polyurethane composite material of Comparative Example 3 is as follows: Figure 12 As shown in Comparative Example 3, the dissipation factor of Comparative Example 3 is 0.43, the glass transition temperature (Tg) is 130°C, the temperature range is 73°C, and damping and shock absorption performance is maintained between 77°C and 150°C. The reason for the reduced damping performance is that the reaction does not include a small molecule disulfide chain extender, which cannot form disulfide bonds that can absorb impact energy at low temperatures. This results in a narrow damping temperature range and an extremely low dissipation factor for the prepared material.

[0082] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A high-damping bio-based polyurethane composite material capable of self-repairing at room temperature, comprising the following raw materials: a flavonoid compound, phenylenediboronic acid, an oligomeric diol, a diisocyanate, a small molecule disulfide chain extender, and a catalyst; The small molecule disulfide chain extender includes one or more of 2,2′-dithiodiethyldiamine dihydrochloride and N,N′(dithiodiylbis(ethane 2,1-diyl))diacrylamide; The flavonoid compound is a flavonoid compound containing an o-triphenolic hydroxyl structure; The method for preparing the room temperature self-repairable high-damping bio-based polyurethane composite material comprises the following steps: S1. dissolving a flavonoid compound and phenyldiboronic acid in a dry solvent and heating the mixture to react to synthesize polymer A; S2. Nitrogen is introduced into the heated oligomer diol, and the solvent is added after stirring while cooling. Then, a diisocyanate and a catalyst are added, and the reaction is carried out by heating and nitrogen is introduced. Then, a small molecule disulfide chain extender is added, and the reaction is continued. Finally, the polymer A is added to obtain a prepolymer after the reaction; S3. removing the solvent of the prepolymer and molding to obtain the high-damping bio-based polyurethane composite material capable of self-repair at room temperature; The molar ratio of the small molecule disulfide chain extender to the polymer A in S2 is (0.52.5):1; The phenylenediboronic acid includes one or more of 2,2′-biphenylenediboronic acid, 1,3-phenylenediboronic acid and 1,4-phenylenediboronic acid; The molar ratio of the flavonoid compound to the phenyldiboronic acid in S1 is 5:2; The heating reaction temperature in S1 is 60-80°C and the time is 12-36h; The molar ratio of the oligomer diol to the polymer A in S2 is (5-8):1; The heating temperature of the oligomer diol in S2 is 100°C, and the cooling is to reduce the temperature to 60°C.

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