Preparation method of a terpyridine functional chain extender and its application in preparing a self-healing conductive polyurethane elastomer
By using bihydroxyl-terminated trippyridine functional chain extender and dynamic supramolecular polymer network technology, the problem of prone to cracks in conductive polyurethane materials is solved, the self-healing and high-performance conductivity of the materials are achieved, and the sustainable development of the materials is promoted.
Patent Information
- Application Number
- CN202310334259.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-31
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2043-03-31
AI Technical Summary
Existing conductive polyurethane materials are prone to cracks or cracks during use, resulting in limited service life and difficult for damaged materials to heal themselves, resulting in environmental pollution and waste of resources.
A bihydroxyl-terminated trippyridine functional chain extender is prepared by substitution reaction, combined with the construction of a dynamic supramolecular polymer network, disulfide bonds, metal ion coordination and urethane bonds are introduced to form a polyurethane material with self-healing properties.
The good conductivity, mechanical properties and room temperature self-healing properties of polyurethane materials are achieved, extending the service life of the materials, and reducing environmental pollution and resource waste.
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Figure CN116514709B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of polymer materials, and particularly relates to a preparation method of a terpyridine functional chain extender and its application in the preparation of a self-healing conductive polyurethane elastomer. Background Art
[0002] Flexible sensors have good mechanical properties and electrical conductivity, and can fit well with the body curve profile, thus attracting wide attention. However, their service life is limited, and cracks or fissures will inevitably occur during use, seriously affecting the service time limit and safety. Most of the damaged materials are scrapped or incinerated, causing serious environmental pollution and resource waste. To achieve the sustainable development of society, it is necessary to prepare a conductive material with good self-healing performance to solve this problem.
[0003] Polyurethane is a polymer material with high strength of plastic and high elasticity of rubber, and its structure is composed of soft segments and hard segments. The soft segments, as flexible chain segments, provide good elastic properties for polyurethane, and the hard segments, as cross-linking points, provide rigidity for polyurethane. Conductive self-healing polyurethane materials require the chain segments to have good fluidity, which conflicts with the high mechanical strength of polyurethane in principle requirements. Introducing dynamic reversible interactions into the main chain of polyurethane can improve the conflict between the two to a certain extent. However, constructing a conductive polyurethane material with both good self-healing performance and mechanical properties is still a challenge.
[0004] Therefore, preparing a self-healing conductive polyurethane elastomer has considerable application prospects. Summary of the Invention
[0005] Aiming at the defects of the prior art, the present invention provides a preparation method of a terpyridine functional chain extender and its application in the preparation of a self-healing conductive polyurethane elastomer. When preparing the self-healing conductive polyurethane elastomer, no solvent is required, pollution is reduced, and a polyurethane material with good electrical conductivity, mechanical properties and room-temperature self-healing performance can be prepared.
[0006] A preparation method of a terpyridine functional chain extender, the terpyridine functional chain extender is a terpyridine functional chain extender capped with two hydroxyl groups, and the preparation method is carried out by a substitution reaction, specifically as follows: under an anhydrous and anaerobic environment, 4'-bromo-2,2':6,2'-terpyridine and triethanolamine are mixed, and then copper iodide and cesium carbonate are added as catalysts. After refluxing and reacting at 100-150 °C for 10-20 h in a sealed environment, it is cooled to room temperature, the organic phase is extracted, and purified by column chromatography.
[0007] Preferably, the molar ratio of 4'-bromo-2,2':6,2'-terpyridine, triethanolamine, copper(I) iodide, and cesium carbonate is 1:(10 - 30):(0.2 - 0.5):(5 - 8).
[0008] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0009] (1) Dehydrate polytetramethylene ether glycol, and then react it with isophorone diisocyanate under the action of a catalyst to obtain a prepolymer. Then add a chain extender and stir until the viscosity increases, and cure at 90 - 110 °C for 10 - 15 h to obtain a polyurethane matrix;
[0010] (2) Dissolve the obtained polyurethane matrix in tetrahydrofuran, add a metal cation salt thereto, stir evenly, and volatilize the solvent to form a film to obtain a high-strength polyurethane;
[0011] (3) Dissolve the obtained high-strength polyurethane in tetrahydrofuran, add a lithium salt thereto, stir evenly, and volatilize the solvent to form a film, then it is done;
[0012] Among them, the chain extender is 4,4'-diaminodiphenyl disulfide and a terpyridine functional chain extender; the terpyridine functional chain extender is prepared by the preparation method described in claim 1 or 2;
[0013] The catalyst is dibutyltin dilaurate;
[0014] The metal cation salt is at least one of ferric chloride hexahydrate and zinc chloride.
[0015] Preferably, the lithium salt is any one of lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, and lithium perchlorate.
[0016] Preferably, the ratio of polytetramethylene ether glycol, isophorone diisocyanate, chain extender, and catalyst is 1 mmol:(2.00 - 2.10) mmol:1 mmol:50 μL.
[0017] Preferably, the molar ratio of 4,4'-diaminodiphenyl disulfide in the chain extender is 25 - 75%, and the rest is the terpyridine functional chain extender.
[0018] Preferably, in step (2), the molar ratio of the metal cation salt to the terpyridine group in the polyurethane matrix is (0.5 - 4.0):1.
[0019] Preferably, in step (3), the mass ratio of the lithium salt to the high-strength polyurethane is (5 - 45):100.
[0020] Preferably, the dehydration is specifically vacuum dehydration treatment at 100 - 120 °C for 2 - 3 h.
[0021] Advantages of the present invention:
[0022] The present invention provides a dihydroxy-terminated terpyridine chain extender. When preparing a polyurethane elastomer, terpyridine groups and disulfide bonds are introduced into the polyurethane main chain through a chain extension effect, and multiple dynamic bonds including disulfide bonds, the coordination of terpyridine with metal ions, the hydrogen bonds of urethane and urea groups, and the loose coordination of lithium ions with oxygen atoms in the polyether soft segment are introduced into the polyurethane backbone to form a dynamic supramolecular polymer network. The disulfide bonds are mainly used to achieve self-healing performance, the coordination of terpyridine with metal ions is mainly used to enhance mechanical properties, the hydrogen bonds are used as sacrificial bonds to dissipate strain energy, and the toughness of the polyurethane is increased through effective reversible bond breakage and recombination. The coordination of lithium ions with oxygen atoms in the polyether soft segment is relatively loose and has a low ionic transport activation energy, which helps to improve the ionic conductivity and provides good conductive performance for the polyurethane. Therefore, a polyurethane material with good conductivity, mechanical properties, and room temperature self-healing performance is obtained. Moreover, the polyurethane prepared by the present invention is obtained through bulk polymerization, without solvents, saving costs, being environmentally friendly, and reducing pollution. Description of the Drawings
[0023] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the dihydroxy-terminated terpyridine chain extender TPYOH prepared in Example 1.
[0024] Figure 2 is the infrared spectrum of the polyurethane prepared in steps (2) and (3) of Example 6.
[0025] Figure 3 is the stress-strain test chart of the high-strength polyurethane prepared in steps (2) of Example 6, Comparative Example 1, and Comparative Example 2.
[0026] Figure 4 is the self-healing performance chart of the conductive polyurethane prepared in Example 6.
[0027] Figure 5 is the sensing performance test of the conductive polyurethane prepared in Example 6. Detailed Embodiments
[0028] Example 1
[0029] A preparation method of a terpyridine functional chain extender, wherein the terpyridine functional chain extender is a terpyridine functional chain extender capped with dihydroxy groups. The preparation method is carried out through a substitution reaction, specifically as follows: Under an anhydrous and anaerobic environment, 4'-bromo-2,2':6,2'-terpyridine (1eq) and triethanolamine (10eq) are added into a sealed tube, and then copper iodide (0.2eq) and cesium carbonate (5eq) are added as catalysts. After refluxing and reacting at 130°C for 18h in a sealed environment, it is cooled to room temperature, the organic phase is extracted, and purified by column chromatography. The obtained pale yellow product is the terpyridine functional chain extender capped with dihydroxy groups.
[0030] Example 2
[0031] A preparation method of a terpyridine functional chain extender, wherein the terpyridine functional chain extender is a terpyridine functional chain extender capped with dihydroxy groups. The preparation method is carried out through a substitution reaction, specifically as follows: Under an anhydrous and anaerobic environment, 4'-bromo-2,2':6,2'-terpyridine (1eq) and triethanolamine (10eq) are added into a sealed tube, and then copper iodide (0.5eq) and cesium carbonate (8eq) are added as catalysts. After refluxing and reacting at 150°C for 18h in a sealed environment, it is cooled to room temperature, the organic phase is extracted, and purified by column chromatography. The obtained pale yellow product is the terpyridine functional chain extender capped with dihydroxy groups.
[0032] Example 3
[0033] A preparation method of a terpyridine functional chain extender, wherein the terpyridine functional chain extender is a terpyridine functional chain extender capped with dihydroxy groups. The preparation method is carried out through a substitution reaction, specifically as follows: Under an anhydrous and anaerobic environment, 4'-bromo-2,2':6,2'-terpyridine (1eq) and triethanolamine (10eq) are added into a sealed tube, and then copper iodide (0.5eq) and cesium carbonate (8eq) are added as catalysts. After refluxing and reacting at 130°C for 14h in a sealed environment, it is cooled to room temperature, the organic phase is extracted, and purified by column chromatography. The obtained pale yellow product is the terpyridine functional chain extender capped with dihydroxy groups.
[0034] Example 4
[0035] A preparation method of a terpyridine functional chain extender, wherein the terpyridine functional chain extender is a terpyridine functional chain extender capped with dihydroxy groups. The preparation method is carried out through a substitution reaction, specifically as follows: Under an anhydrous and anaerobic environment, 4'-bromo-2,2':6,2'-terpyridine (1eq) and triethanolamine (30eq) are added into a sealed tube, and then copper iodide (0.5eq) and cesium carbonate (8eq) are added as catalysts. After refluxing and reacting at 100 °C for 20 h in a sealed environment, it is cooled to room temperature, the organic phase is extracted, and purified by column chromatography. The obtained pale yellow product is the terpyridine functional chain extender capped with dihydroxy groups.
[0036] Example 5
[0037] A preparation method of a terpyridine functional chain extender, wherein the terpyridine functional chain extender is a terpyridine functional chain extender capped with dihydroxy groups. The preparation method is carried out through a substitution reaction, specifically as follows: Under an anhydrous and anaerobic environment, 4'-bromo-2,2':6,2'-terpyridine (1eq) and triethanolamine (10eq) are added into a sealed tube, and then copper iodide (0.2eq) and cesium carbonate (5eq) are added as catalysts. After refluxing and reacting at 150 °C for 10 h in a sealed environment, it is cooled to room temperature, the organic phase is extracted, and purified by column chromatography. The obtained pale yellow product is the terpyridine functional chain extender capped with dihydroxy groups.
[0038] Example 6
[0039] A preparation method of a self-healing conductive polyurethane elastomer is specifically as follows:
[0040] (1) Poly(tetramethylene ether) glycol (1.00 mmol, 2.000 g) is vacuum-treated at 120 °C for 3 h to remove the moisture therein, isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate are added, and rapidly stirred evenly to form a prepolymer; then 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine functional chain extender prepared in Example 1 (0.50 mmol, 0.190 g) are added, and rapidly stirred until the viscosity increases, and is placed in an oven and cured at 100 °C for 12 h to obtain a polyurethane matrix, which is pale yellow;
[0041] (2) The polyurethane matrix obtained in step (1) is dissolved in tetrahydrofuran, zinc chloride (0.136 g, 1 mmol) is added thereto, and stirred evenly. After its coordination reaction occurs, it is transferred into a tetrafluoro mold, and the solvent is volatilized to form a film to obtain a high-strength polyurethane;
[0042] (3) Dissolve 2.0 g of the high-strength polyurethane obtained in step (2) in tetrahydrofuran, add 0.700 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, transfer it to a tetrafluoro mold, and volatilize the solvent to form a film.
[0043] Example 7
[0044] Take the terpyridine functional chain extender prepared in Example 2, and the others are the same as in Example 6.
[0045] Example 8
[0046] Take the terpyridine functional chain extender prepared in Example 3, and the others are the same as in Example 6.
[0047] Example 9
[0048] In step (1), vacuum-treat polytetramethylene ether glycol (1.00 mmol, 2.000 g) at 120 °C for 2 h to remove the moisture therein, and the others are the same as in Example 6.
[0049] Example 10
[0050] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0051] (1) Vacuum-treat polytetramethylene ether glycol (1.00 mmol, 2.000 g) at 120 °C for 3 h to remove the moisture therein, add isophorone diisocyanate (2.00 mmol, 0.444 g) and 50 μL of dibutyltin dilaurate, stir quickly and evenly to form a prepolymer; then add 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine functional chain extender prepared in Example 1 (0.50 mmol, 0.190 g), stir quickly until the viscosity increases, and cure it in an oven at 100 °C for 12 h to obtain a polyurethane matrix, which is light yellow;
[0052] (2) Dissolve the polyurethane matrix obtained in step (1) in tetrahydrofuran, add zinc chloride (0.136 g, 1 mmol) thereto, stir evenly, wait for the coordination reaction to occur, transfer it to a tetrafluoro mold, volatilize the solvent, and form a film to obtain a high-strength polyurethane;
[0053] (3) Dissolve 2.0 g of the high-strength polyurethane obtained in step (2) in tetrahydrofuran, add 0.700 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, transfer it to a tetrafluoro mold, and volatilize the solvent to form a film.
[0054] Example 11
[0055] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0056] (1) Poly(tetramethylene ether) glycol (1.00 mmol, 2.000 g) was vacuum-treated at 120 °C for 3 h to remove the moisture therein, isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate were added, and the mixture was quickly stirred evenly to form a prepolymer; then 4,4'-diaminodiphenyl disulfide (0.25 mmol, 0.062 g) and the terpyridine-functional chain extender prepared in Example 1 (0.75 mmol, 0.285 g) were added, and the mixture was quickly stirred until the viscosity increased, and then placed in an oven and cured at 100 °C for 12 h to obtain a polyurethane matrix, which was light yellow;
[0057] (2) The polyurethane matrix obtained in step (1) was dissolved in tetrahydrofuran, zinc chloride (0.136 g, 1 mmol) was added thereto, and the mixture was stirred evenly. After the coordination reaction occurred, it was transferred into a tetrafluoro mold, and the solvent was volatilized to form a film, obtaining a high-strength polyurethane;
[0058] (3) Take 2.0 g of the high-strength polyurethane obtained in step (2) and dissolve it in tetrahydrofuran, add 0.700 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, then transfer it into a tetrafluoro mold, and volatilize the solvent to form a film, and that's it.
[0059] Example 12
[0060] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0061] (1) Poly(tetramethylene ether) glycol (1.00 mmol, 2.000 g) was vacuum-treated at 120 °C for 3 h to remove the moisture therein, isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate were added, and the mixture was quickly stirred evenly to form a prepolymer; then 4,4'-diaminodiphenyl disulfide (0.75 mmol, 0.186 g) and the terpyridine-functional chain extender prepared in Example 1 (0.25 mmol, 0.095 g) were added, and the mixture was quickly stirred until the viscosity increased, and then placed in an oven and cured at 100 °C for 12 h to obtain a polyurethane matrix, which was light yellow;
[0062] (2) The polyurethane matrix obtained in step (1) was dissolved in tetrahydrofuran, zinc chloride (0.136 g, 1 mmol) was added thereto, and the mixture was stirred evenly. After the coordination reaction occurred, it was transferred into a tetrafluoro mold, and the solvent was volatilized to form a film, obtaining a high-strength polyurethane;
[0063] (3) Dissolve 2.0 g of the high-strength polyurethane obtained in step (2) in tetrahydrofuran, add 0.700 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, transfer it to a tetrafluoro mold, and volatilize the solvent to form a film.
[0064] Example 13
[0065] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0066] (1) Vacuum-treat polytetramethylene ether glycol (1.00 mmol, 2.000 g) at 120 °C for 3 h to remove the moisture therein, add isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate, stir quickly and evenly to form a prepolymer; then add 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine-functionalized chain extender prepared in Example 1 (0.50 mmol, 0.190 g), stir quickly until the viscosity increases, and place it in an oven to cure at 100 °C for 12 h to obtain a polyurethane matrix, which is light yellow;
[0067] (2) Dissolve the polyurethane matrix obtained in step (1) in tetrahydrofuran, add ferric chloride hexahydrate (0.270 g, 1 mmol) thereto, stir evenly, wait for the coordination reaction to occur, transfer it to a tetrafluoro mold, volatilize the solvent, and form a film to obtain a high-strength polyurethane;
[0068] (3) Dissolve 2.0 g of the high-strength polyurethane obtained in step (2) in tetrahydrofuran, add 0.700 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, transfer it to a tetrafluoro mold, and volatilize the solvent to form a film.
[0069] Example 14
[0070] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0071] (1) Vacuum-treat polytetramethylene ether glycol (1.00 mmol, 2.000 g) at 120 °C for 3 h to remove the moisture therein, add isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate, stir quickly and evenly to form a prepolymer; then add 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine-functionalized chain extender prepared in Example 1 (0.50 mmol, 0.190 g), stir quickly until the viscosity increases, and place it in an oven to cure at 100 °C for 12 h to obtain a polyurethane matrix, which is light yellow;
[0072] (2) Dissolve the polyurethane matrix obtained in step (1) in tetrahydrofuran, add zinc chloride (0.068 g, 0.5 mmol) thereto, stir evenly, and after the coordination reaction occurs, transfer it into a tetrafluoro mold, volatilize the solvent to form a film, and obtain a high-strength polyurethane;
[0073] (3) Take 2.0 g of the high-strength polyurethane obtained in step (2) and dissolve it in tetrahydrofuran, add 0.700 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, then transfer it into a tetrafluoro mold, and volatilize the solvent to form a film. That's it.
[0074] Example 15
[0075] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0076] (1) Vacuum-treat polytetramethylene ether glycol (1.00 mmol, 2.000 g) at 120 °C for 3 h to remove the moisture therein, add isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate, stir quickly and evenly to form a prepolymer; then add 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine-functionalized chain extender prepared in Example 1 (0.50 mmol, 0.190 g), stir quickly until the viscosity increases, and cure it in an oven at 100 °C for 12 h to obtain a polyurethane matrix, which is light yellow;
[0077] (2) Dissolve the polyurethane matrix obtained in step (1) in tetrahydrofuran, add zinc chloride (0.272 g, 2 mmol) thereto, stir evenly, and after the coordination reaction occurs, transfer it into a tetrafluoro mold, volatilize the solvent to form a film, and obtain a high-strength polyurethane;
[0078] (3) Take 2.0 g of the high-strength polyurethane obtained in step (2) and dissolve it in tetrahydrofuran, add 0.700 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, then transfer it into a tetrafluoro mold, and volatilize the solvent to form a film. That's it.
[0079] Example 16
[0080] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0081] (1) Poly(tetramethylene ether) glycol (1.00 mmol, 2.000 g) was vacuum-treated at 120 °C for 3 h to remove the moisture therein. Isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate were added, and the mixture was rapidly stirred evenly to form a prepolymer. Then, 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine-functional chain extender prepared in Example 1 (0.50 mmol, 0.190 g) were added, and the mixture was rapidly stirred until the viscosity increased. It was placed in an oven and cured at 100 °C for 12 h to obtain a polyurethane matrix, which was light yellow;
[0082] (2) The polyurethane matrix obtained in step (1) was dissolved in tetrahydrofuran. Zinc chloride (0.136 g, 1 mmol) was added thereto, and the mixture was stirred evenly. After the coordination reaction occurred, it was transferred into a tetrafluoro mold, and the solvent was volatilized to form a film, obtaining a high-strength polyurethane;
[0083] (3) Take 2.0 g of the high-strength polyurethane obtained in step (2) and dissolve it in tetrahydrofuran. Add 0.300 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, then transfer it into a tetrafluoro mold, and volatilize the solvent to form a film, and that's it.
[0084] Example 17
[0085] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0086] (1) Poly(tetramethylene ether) glycol (1.00 mmol, 2.000 g) was vacuum-treated at 120 °C for 3 h to remove the moisture therein. Isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate were added, and the mixture was rapidly stirred evenly to form a prepolymer. Then, 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine-functional chain extender prepared in Example 1 (0.50 mmol, 0.190 g) were added, and the mixture was rapidly stirred until the viscosity increased. It was placed in an oven and cured at 100 °C for 12 h to obtain a polyurethane matrix, which was light yellow;
[0087] (2) The polyurethane matrix obtained in step (1) was dissolved in tetrahydrofuran. Zinc chloride (0.136 g, 1 mmol) was added thereto, and the mixture was stirred evenly. After the coordination reaction occurred, it was transferred into a tetrafluoro mold, and the solvent was volatilized to form a film, obtaining a high-strength polyurethane;
[0088] (3) Take 2.0 g of the high-strength polyurethane obtained in step (2) and dissolve it in tetrahydrofuran. Add 0.900 g of lithium bis(trifluoromethanesulfonyl)imide thereto, stir evenly, then transfer it into a tetrafluoro mold, and volatilize the solvent to form a film, and that's it.
[0089] Example 18
[0090] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0091] (1) Poly(tetramethylene ether) glycol (1.00 mmol, 2.000 g) was vacuum-treated at 120 °C for 3 h to remove the moisture therein, isophorone diisocyanate (2.04 mmol, 0.453 g) and 50 μL of dibutyltin dilaurate were added, and the mixture was rapidly stirred evenly to form a prepolymer; then 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine-functional chain extender prepared in Example 1 (0.50 mmol, 0.190 g) were added, and the mixture was rapidly stirred until the viscosity increased, and then cured in an oven at 100 °C for 12 h to obtain a polyurethane matrix, which was light yellow;
[0092] (2) The polyurethane matrix obtained in step (1) was dissolved in tetrahydrofuran, zinc chloride (0.034 g, 0.25 mmol) was added thereto, and the mixture was stirred evenly. After the coordination reaction occurred, it was transferred into a tetrafluoro mold, and the solvent was volatilized to form a film, obtaining a high-strength polyurethane;
[0093] (3) 2.0 g of the high-strength polyurethane obtained in step (2) was dissolved in tetrahydrofuran, 0.900 g of lithium perchlorate was added thereto, and the mixture was stirred evenly and then transferred into a tetrafluoro mold, and the solvent was volatilized to form a film, and that's it.
[0094] Example 19
[0095] A preparation method of a self-healing conductive polyurethane elastomer is as follows:
[0096] (1) Poly(tetramethylene ether) glycol (1.00 mmol, 2.000 g) was vacuum-treated at 120 °C for 3 h to remove the moisture therein, isophorone diisocyanate (2.10 mmol, 0.466 g) and 50 μL of dibutyltin dilaurate were added, and the mixture was rapidly stirred evenly to form a prepolymer; then 4,4'-diaminodiphenyl disulfide (0.50 mmol, 0.124 g) and the terpyridine-functional chain extender prepared in Example 1 (0.50 mmol, 0.190 g) were added, and the mixture was rapidly stirred until the viscosity increased, and then cured in an oven at 100 °C for 12 h to obtain a polyurethane matrix, which was light yellow;
[0097] (2) Dissolve the polyurethane matrix obtained in step (1) in tetrahydrofuran, add zinc chloride (0.034 g, 0.25 mmol) thereto, stir evenly, and after the coordination reaction occurs, transfer it into a tetrafluoro mold, volatilize the solvent to form a film, and obtain a high-strength polyurethane;
[0098] (3) Take 2.0 g of the high-strength polyurethane obtained in step (2) and dissolve it in tetrahydrofuran, add 0.100 g of lithium trifluoromethanesulfonate thereto, stir evenly, then transfer it into a tetrafluoro mold, and volatilize the solvent to form a film.
[0099] Comparative Example 1
[0100] Do not add the terpyridine functional chain extender, and the others are the same as in Example 6.
[0101] Comparative Example 2
[0102] Use 1,4-butanediol to replace the terpyridine functional chain extender in Example 6, and the others are the same as in Example 6.
[0103] Performance Testing
[0104] 1. Characterization of the dihydroxy-terminated terpyridine functional chain extender
[0105] Take the product of Example 1, dissolve it in deuterated chloroform, and perform a nuclear magnetic resonance hydrogen spectrum test at 400 MHz. As Figure 1 shown, the proton peaks at 8.65, 8.58, 8.00, 7.82, and 7.31 correspond to the hydrogens at different positions on the six-membered ring of the terpyridine group, and the proton peaks at 4.35, 3.68, 3.11, and 2.84 correspond to the a-position and b-position methylene groups connected to the tertiary amine nitrogen. The integral area is consistent with the ratio of the number of corresponding hydrogen atoms in the structural formula, indicating that the dihydroxy-terminated terpyridine functional chain extender was successfully synthesized in Example 1 of the present invention.
[0106] 2. Characterization of the self-healing polyurethane elastomer
[0107] Perform infrared testing on the polyurethane elastomers obtained in steps (2) and (3) of Example 6. As Figure 2 shown, the stretching vibration peak of isocyanate at 2270 cm -1 was not observed in the spectrum, proving that the isocyanate completely participated in the reaction. The absorption peak at 3334 cm -1 belongs to the N-H stretching vibration peak of urethane, and the absorption peak at 1702 cm -1 belongs to the stretching vibration peak of C=O, proving that urethane bonds appeared in the sample, indicating that the hydroxyl or amino group reacted with the isocyanate, and polyurethane was successfully prepared; the stretching vibration peak of C-N in the pyridine ring generally appears at 1600 cm -1At [specific position], after the coordination with zinc ions, the stretching vibration peak of C-N shows a certain degree of red shift and moves to 1615 cm -1 At [specific position], which proves that zinc ions do coordinate with the terpyridine group; when lithium bis(trifluoromethanesulfonyl)imide is added, that is, the polyurethane sample obtained in step (3) shows an absorption peak at 1058 cm -1 At [specific position], which is attributed to the S-N-S stretching vibration peak on lithium bis(trifluoromethanesulfonyl)imide, and the absorption peak of the carbonyl group moves from 1702 cm -1 At [specific position] to a lower wavenumber and appears at 1694 cm -1 At [specific position], indicating that lithium bis(trifluoromethanesulfonyl)imide is successfully introduced into the polyurethane and coordinates with the polyether soft segment.
[0108] 3. Mechanical property testing
[0109] The high-strength polyurethanes obtained in step (2) of Example 6, Comparative Example 1 and Comparative Example 2 were stretched on an electronic universal testing machine at a tensile rate of 50 mm / min at room temperature, and the results are as Figure 3 shown. When the molar ratio of 4,4'-diaminodiphenyl disulfide to the terpyridine functional chain extender is 1:1 and the molar ratio of zinc ions to the terpyridine group is 2:1, the prepared polyurethane has excellent mechanical properties, with a fracture stress of 12.85 MPa, an elongation at break of 1660%, and a toughness of 107.09 MJ / m 3 , and its mechanical properties far exceed those of Comparative Example 1 and Comparative Example 2.
[0110] 4. Self-healing property testing
[0111] The self-healing conductive polyurethane elastomer obtained in Example 6 was cut in half with scissors, and then the two parts were re-spliced together along the cross-section and placed at 30 °C for the sample to self-heal for a certain period of time. Then the healed sample was subjected to a mechanical tensile test to calculate its self-healing efficiency. As Figure 4 shown, the polyurethane material was subjected to a self-healing test at room temperature of 30 °C for a certain period of time. As time prolongs, the self-healing efficiency of the polyurethane increases significantly. When self-healing for 8 h, the fracture stress is 0.51 MPa and the self-healing efficiency of toughness is 52.4%. When the time is extended to 12 h, the fracture stress increases to 0.74 MPa and the self-healing fracture efficiency of toughness is 96.9%, basically recovering to the original value, indicating that the polyurethane has good self-healing properties.
[0112] 5. Conductive sensing testing
[0113] The self-healing conductive polyurethane elastomer obtained in Example 6 was subjected to conductive sensing tests. The polyurethane sample was closely attached to the finger and wrist parts and connected to a general-purpose source meter through wires. As the finger and wrist moved, the strain response was monitored by recording the relative change in resistance (ΔR / R0 = (R - R0) / R0, where R is the instantaneous resistance and R0 is the initial resistance), thereby detecting the conductive effect of the polyurethane. As Figure 5 shown, when the finger was bent from 0° to 30°, 60°, and then to 90°, the polyurethane sensor was stretched. Correspondingly, an electrical signal with a gradually increasing relative resistance could be clearly observed. When the finger gradually returned to the straight state, the relative resistance change also returned to the initial value ( Figure 5 Figure a in the middle). Similarly, the polyurethane sensor could also monitor the bending movement of the wrist. When the wrist was bent from the straight state to 90° and then straightened, it was found that it could still quickly respond to the change, and the relative resistance change value was stably maintained at about 25% ( Figure 5 Figure b in the middle). These results all indicate that this polyurethane elastomer has excellent properties of rapid response and stable sensing, and has great potential application prospects in the field of wearable intelligent sensors.
Claims
1. A preparation method of a self-healing conductive polyurethane elastomer, characterized in that: The preparation method is as follows: (1) Dehydrate polytetramethylene ether glycol, and then react it with isophorone diisocyanate under the action of a catalyst to obtain a prepolymer. Then add a chain extender and stir until the viscosity increases, and cure at 90 - 110 °C for 10 - 15 h to obtain a polyurethane matrix; (2) Dissolve the obtained polyurethane matrix in tetrahydrofuran, add a metal cation salt thereto, stir evenly, and volatilize the solvent to form a film to obtain a high-strength polyurethane; (3) Dissolve the obtained high-strength polyurethane in tetrahydrofuran, add a lithium salt thereto, stir evenly, and then volatilize the solvent to form a film, and that's it; Among them, the chain extender is 4,4'-diaminodiphenyl disulfide and a terpyridine functional chain extender; The catalyst is dibutyltin dilaurate; The metal cation salt is at least one of ferric chloride hexahydrate and zinc chloride; The terpyridine functional chain extender is prepared by the following method: Under an anhydrous and anaerobic environment, mix 4'-bromo-2,2':6,2'-terpyridine and triethanolamine, and then add copper iodide and cesium carbonate as catalysts. After refluxing and reacting at 100 - 150 °C for 10 - 20 h in a sealed environment, cool to room temperature, extract the organic phase, and purify by column chromatography, and that's it.
2. The preparation method of the self-healing conductive polyurethane elastomer according to claim 1, characterized in that: The molar ratio of 4'-bromo-2,2':6,2'-terpyridine, triethanolamine, copper iodide, and cesium carbonate is 1:(10 - 30):(0.2 - 0.5):(5 - 8).
3. The preparation method of the self-healing conductive polyurethane elastomer according to claim 1 or 2, characterized in that: The lithium salt is any one of lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, and lithium perchlorate.
4. The preparation method of the self-healing conductive polyurethane elastomer according to claim 3, characterized in that: The ratio of polytetramethylene ether glycol, isophorone diisocyanate, chain extender, and catalyst is 1 mmol:(2.00 - 2.10) mmol:1 mmol:50 μL.
5. The preparation method of the self-healing conductive polyurethane elastomer according to claim 4, characterized in that: The molar ratio of 4,4'-diaminodiphenyl disulfide in the chain extender is 25 - 75%, and the rest is the terpyridine functional chain extender.
6. The preparation method of the self-healing conductive polyurethane elastomer according to claim 4, wherein: In step (2), the molar ratio of the metal cation salt to the terpyridine group in the polyurethane matrix is (0.5 - 4.0):
1.
7. The preparation method of the self-healing conductive polyurethane elastomer according to claim 6, wherein: In step (3), the mass ratio of the lithium salt to the high-strength polyurethane is (5 - 45):
100.
8. The preparation method of the self-healing conductive polyurethane elastomer according to claim 1 or 2, characterized in that: The dehydration is specifically vacuum dehydration treatment at 100 - 120 °C for 2 - 3 h.