Near-infrared responsive self-healing photocured polyurethane material and preparation method and application thereof

Abstract

The application discloses a kind of near-infrared response self-repairing photocuring polyurethane material and its preparation method and application, belong to high polymer material technical field.The method for preparing the material includes the following steps: first, the polyurethane oligomer containing thio carbamate bond is prepared;Then, it is mixed with polydopamine nanoparticle, acrylate monomer and photoinitiator;Finally, under the irradiation of ultraviolet light, the near-infrared light response self-repairing photocuring polyurethane material based on thio carbamate bond is obtained.The beneficial effects of the application are that: (1) the material can have excellent self-repairing ability and photo-induced effect under the stimulation of 980nm near-infrared light;(2) the material also has good degradation performance, effectively solves the problem that material waste can cause serious environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a near-infrared responsive self-healing photocurable polyurethane material, its preparation method, and its application. Background Technology

[0002] Photocurable polyurethane (PPU) materials are widely used due to the strong polarity of the urethane bonds in the polymer segments and the presence of hydrogen bonds between segments, which can form effective physical cross-linking points to enhance the mechanical properties of the material. They also possess excellent chemical resistance and high / low temperature resistance. However, the inability to effectively release internal stress during the photocuring process leads to weak points and defects within the material, making it prone to breakage and fracture during use, thus limiting the application of PPU materials in some high-end fields. Imparting self-healing capabilities to PPU materials can effectively solve this problem; therefore, designing and preparing novel self-healing PPU materials is of great significance for broadening the application range of PPU materials.

[0003] Thiocarbamate bonds are a novel type of reversible covalent bond that has been studied in recent years. Their construction benefits from abundant raw materials, simple preparation, and high reaction yields. Furthermore, thiocarbamate bonds can be cleaved in alcohol solvents, thus imparting biodegradability to materials. Therefore, they have shown great application potential in both self-healing and biodegradable materials. Applying thiocarbamate bonds to photocurable polyurethane materials is expected to endow them with excellent repair properties, extend their lifespan, and make them biodegradable.

[0004] However, there are currently few reports on photocurable self-healing materials based on thiocarbamate bonds, and most of these materials rely on heating for repair. Heat-based repair wastes energy; furthermore, the entire material needs to be heated during the repair process, causing even undamaged areas to age and reducing the material's lifespan. Light, on the other hand, is an inexpensive and clean energy source that does not introduce any chemicals during the repair process, thus causing no damage to the material. Moreover, light allows for remote and real-time control of the self-healing process, enabling localized, targeted repair, making it a hot research topic in self-healing materials.

[0005] Chinese patent application CN113788927A discloses a self-healing polyurethane material and its preparation method. The method employs a stepwise preparation process: first, a disulfide-bonded macromolecular diol is obtained; then, a disulfide-bonded polyurethane solution is prepared using the disulfide-bonded macromolecular diol as a raw material; simultaneously, a hard-segment polyurethane solution is prepared using a conventional macromolecular diol as a raw material; finally, the two polyurethane solutions are mixed in a certain proportion and cast to obtain a self-healing polyurethane material with excellent mechanical properties. The self-healing polyurethane material provided by this patent can be applied to flexible electronic devices. However, the self-healing ability of this material is relatively poor, therefore, further improvement is needed. Summary of the Invention

[0006] The technical problem to be solved by this invention is how to solve the problem of poor self-healing ability of existing polyurethane materials.

[0007] The present invention solves the above-mentioned technical problems through the following technical means:

[0008] The first aspect of this invention provides a method for preparing a near-infrared responsive self-healing photocurable polyurethane material, comprising the following steps:

[0009] (1) Preparation of polyurethane oligomers containing thiocarbamate bonds:

[0010] The macromolecular chain extender, catalyst 1, and diisocyanate were heated and reacted. When the remaining amount of -NCO was 50%, the small molecule alcohol chain extender was dissolved in organic solvent 1 and added dropwise to the reaction system to continue the reaction. Then, the small molecule thiol chain extender and catalyst 2 were dissolved in organic solvent 1 and added dropwise to the reaction system to continue the reaction. Finally, an end-capping agent was added to the reaction system to continue the reaction until the amount of -NCO was 0. Organic solvent 1 was then removed to obtain a polyurethane oligomer containing thiocarbamate bonds.

[0011] (2) Preparation of polydopamine nanoparticles (PDA):

[0012] Organic solvent 2, solvent 3 and water are mixed, then dopamine hydrochloride (DA) monomer is added to it, the mixture is heated to react, centrifuged, the lower layer of solid is removed and dried to obtain polydopamine nanoparticles (PDA).

[0013] (3) The polyurethane oligomer containing thiocarbamate bonds prepared above, polydopamine nanoparticles (PDA), acrylate monomers and photoinitiators are mixed and cured under ultraviolet light to obtain a near-infrared photoresponsive self-healing photocurable polyurethane material based on thiocarbamate bonds.

[0014] The macromolecular chain extender is selected from one or more of polyether diols or polyether polyols with a molecular weight of 200 to 10,000, and polyester diols or polyester polyols with a molecular weight of 1,000 to 10,000.

[0015] Beneficial effects: This invention first prepares polyurethane oligomers containing thiocarbamate bonds; then, mixes them with polydopamine nanoparticles, commercial acrylate monomers, and photoinitiators; finally, under ultraviolet light irradiation, a near-infrared photoresponsive self-healing photocurable polyurethane material based on thiocarbamate bonds is obtained. The healing of material damage is achieved through the photothermal conversion ability of polydopamine nanoparticles under near-infrared light irradiation, thus improving the self-healing ability of the material.

[0016] Preferably, the macromolecular chain extender is polyethylene glycol with a molecular weight of 1000-2000.

[0017] The diisocyanate is selected from one or more of 1,6-hexanediisocyanate (HDI), isophorone diisocyanate (IPDI), trimethyl 1,6-hexanediisocyanate (TMHDI), hydrogenated 4,4-diphenylmethane diisocyanate (HMDI), transcyclohexane isocyanate (CHDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), diphenylmethylene diisocyanate (XDI), tetramethylxylenylidene diisocyanate (TMXDI), dicyclohexylmethane diisocyanate (HMDI), and methylcyclohexyl diisocyanate (HTDI).

[0018] Preferably, the diisocyanate is isophorone diisocyanate (IPDI).

[0019] The small molecule alcohol chain extender is selected from C2-C16 binary or polyols.

[0020] Preferably, the small molecule alcohol chain extender is a C2-C16 diol.

[0021] Preferably, the small molecule alcohol chain extender is a C2-C16 straight-chain diol.

[0022] Preferably, the small molecule alcohol chain extender is a C2-C6 straight-chain diol.

[0023] The small molecule thiol chain extender is selected from C2-C16 binary or polythiols.

[0024] Preferably, the small molecule thiol chain extender is a C2-C16 dithiol.

[0025] Preferably, the small molecule thiol chain extender is a C2-C16 straight-chain dithiol.

[0026] Preferably, the small molecule thiol chain extender is a C2-C6 straight-chain dithiol.

[0027] Catalyst 1 and Catalyst 2 are both selected from one or more of organobismuth catalysts, organotin catalysts, and amine catalysts.

[0028] Preferably, the organic bismuth catalyst is selected from one or more of bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, and bismuth naphthenate.

[0029] Preferably, the organotin catalyst is selected from one or more of monobutyltin oxide, dibutyltin oxide, dibutyltin diacetate, and dibutyltin dilaurate.

[0030] Preferably, the amine catalyst is selected from one or more of triethylamine, 1,5-diazabicyclo[4,3,0]-5-nonene, and N,N-diisopropylethylamine.

[0031] Preferably, the catalyst 1 is dibutyltin dilaurate.

[0032] Preferably, the catalyst 2 is 1,5-diazabicyclo[4,3,0]-5-nonene.

[0033] Preferably, the organic solvent 1 is selected from one or more of dimethyl sulfoxide, acetone, dioxane, tetrahydrofuran, methyl formate, methyl ethyl ketone, butyl acetate, propylene glycol methyl ether acetate, ethyl acetate, and isopropyl ether.

[0034] Preferably, the organic solvent 1 is tetrahydrofuran.

[0035] Preferably, the capping agent is one or more of hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), hydroxyethyl methacrylate (HEMA), and hydroxypropyl methacrylate (HPMA).

[0036] Preferably, in the reaction system of step (1), the ratio of the molar number of -NCO groups in the isocyanate raw material to the total molar number of hydroxyl and mercapto groups in the system is 1:1.

[0037] Preferably, the number average molecular weight of the polyurethane oligomer containing thiocarbamate bonds obtained in step (1) is 7000-15000; the content of thiocarbamate bonds in the polyurethane oligomer containing thiocarbamate bonds is 0.5wt%-10wt%.

[0038] Preferably, the organic solvent 2 is an alcohol compound. Preferably, the organic solvent 2 is anhydrous ethanol.

[0039] Preferably, the solvent 3 is an alkaline substance. Preferably, the solvent 3 is ammonia.

[0040] Preferably, the acrylate monomer is one or more of the following: monofunctional, difunctional, or polyfunctional acrylate monomers, methacrylate monomers, acrylic acid, acrylamide, methacrylic acid, and methacrylamide.

[0041] Preferably, the photoinitiator is selected from one or more of 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (2959), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), methyl acetophenone (MBF), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO), or a mixture thereof.

[0042] A second aspect of the present invention provides a near-infrared light-stimulated self-healing photocurable polyurethane material prepared by the above preparation method.

[0043] The near-infrared responsive self-healing photocurable polyurethane material consists of two parts: the first component: 10-60 wt% polyurethane oligomer containing thiocarbamate bonds; 40-90 wt% monomer containing reactive diluent; the second component (based on the first component as 100%): 0.5-5 wt% photoinitiator and 0.5-5 wt% polydopamine nanoparticles.

[0044] Beneficial effects: The fracture stress of this material is 0.5-3MPa, and the elongation at break is 100-1500%; it has good self-healing properties under 980nm near-infrared irradiation; the material can be degraded in alcohol solvents.

[0045] A third aspect of the present invention proposes the application of the near-infrared light-stimulated self-healing photocurable polyurethane material prepared by the above preparation method in flexible conductive materials and photoactuated materials.

[0046] Synthesis principle

[0047] The following example, using the preparation of a near-infrared light-responsive self-healing photocurable polyurethane material from selected raw materials, illustrates the synthesis principle.

[0048] 1. First, weigh out the raw materials polyethylene glycol-1000, isophorone diisocyanate, and catalyst dibutyltin dilaurate and add them to a flask. Replace the reaction atmosphere with nitrogen by evacuating and purging with nitrogen to prevent the influence of water vapor in the air on the reaction system. Then, place the system at 80°C for reaction. After 4 hours of reaction, weigh out 1,4-butanediol and dissolve it in anhydrous tetrahydrofuran (THF). Slowly add it dropwise to a three-necked flask using a syringe. After the addition is complete, continue the reaction at 80°C for 4 hours until the -OH group is completely reacted. Then, weigh out 1,3-propanedithiol and dissolve it in anhydrous THF. Add 1,5-diazabicyclo[4.3.0]-5-nonene, remove it with a syringe, and slowly add it dropwise to a three-necked flask. After the addition is complete, continue the reaction at 80°C for 5 hours. Finally, weigh out hydroxyethyl acrylate and dissolve it in anhydrous THF. Slowly add it dropwise to a three-necked flask. Stop the reaction 5 hours after the addition is complete. After removing tetrahydrofuran, the polyurethane oligomer PETU-B3S4 is obtained. In the reaction system, the ratio of the molar number of -NCO groups in the isocyanate raw material to the total molar number of hydroxyl and mercapto groups in the system is 1:1.

[0049] The reaction formula is as follows:

[0050]

[0051] The infrared spectrum, 1H NMR spectrum, and Raman spectrum of compound PETU-B3S4 are shown in the appendix. Figure 1 Appendix Figure 2 and attached Figure 3 The relevant data is as follows:

[0052] FTIR(KBr,cm -1 )3336(-NHCOS-and-NHCOO-),2954and 2865(-CH3 and-CH2-),1716(-C=O),812(-CH=CH2).

[0053] 1 H NMR (400MHz, Chloroform-d) δ6.67-5.90(-OOCCH=CH2),5.40-4.98(-NHCOS-,-NHCOO-),4.32-3.98(-NHCOOCH2-,-O-CH2-CH2-OOCCH=CH2),3.64(-CH2 of PEG-1000,-CH-NHCOO,-CH-NHCOS),3.01-2.77(-CH2-NHCOO,-CH2-NHCOS,-NHCOS-CH2),1.92-1.79(-CH2 ofIPDI,-NHCOOCH2-CH2),1.07-0.86(-CH3 of IPDI).

[0054] The molecular weight test results of compound PETU-B3S4 are as follows: number average molecular weight / Mn: 14052, dispersion index (PDI): 2.46.

[0055] 2. Take anhydrous CH3CH2OH, ammonia water, and H2O separately and mix them together. Then add dopamine hydrochloride (DA) monomer to the mixture. The reaction system changes from colorless to dark brown. React at 30℃ for 28 hours. After the reaction is complete, centrifuge the solution and dry the lower solid layer in a vacuum drying oven at 65℃ for 6 hours to obtain the product PDA. The infrared spectrum of the product PDA is shown in the appendix. Figure 10 .

[0056] 3. First, weigh a certain amount of PDA and dissolve it in anhydrous tetrahydrofuran (THF). Sonicate the solution for a certain time to ensure uniform dispersion within the THF. After sonication, mix the PDA with PETU-B3S4 oligomer and continue sonicating until the PDA and oligomer are evenly mixed. Then remove the THF. Mix the oligomer with the PDA and other monomers, including hydroxyethyl acrylate (HEA), isobornyl acrylate (IBOA), and the photoinitiator BAPO, to prepare a photosensitive liquid. Spread the prepared photosensitive liquid evenly onto a dumbbell-shaped polytetrafluoroethylene mold. Then, cover the mold with a layer of polyvinyl butyral film to prevent oxygen inhibition from contacting the photosensitive liquid with air, which could lead to incomplete curing. Finally, place the mold under a UV lamp for curing to obtain a photocurable polyurethane material.

[0057] The advantages of this invention are:

[0058] 1. This invention first prepares a polyurethane oligomer containing thiocarbamate bonds; then, it mixes it with polydopamine nanoparticles, acrylate monomers and photoinitiators; finally, it obtains a near-infrared photoresponsive self-healing photocurable polyurethane material based on thiocarbamate bonds under ultraviolet light irradiation. The healing of the damaged area of ​​the material is achieved by the photothermal conversion ability of polydopamine nanoparticles under near-infrared light irradiation, thereby improving the self-healing ability of the material.

[0059] 2. This material exhibits excellent self-healing ability and photo-actuation effect under 980nm near-infrared stimulation;

[0060] 3. The material also has good degradation properties, which effectively solves the problem of serious environmental pollution caused by the disposal of the material. Attached Figure Description

[0061] Figure 1 This is the infrared spectrum of PETU-B3S4 prepared in Example 1;

[0062] Figure 2 This is the 1H NMR spectrum of PETU-B3S4 prepared in Example 1;

[0063] Figure 3 This is the Raman spectrum of PETU-B3S4 prepared in Example 1;

[0064] Figure 4 This is the infrared spectrum of PTTU-B3S4 prepared in Example 2;

[0065] Figure 5 This is the 1H NMR spectrum of PTTU-B3S4 prepared in Example 2;

[0066] Figure 6 This is the Raman spectrum of PTTU-B3S4 prepared in Example 2;

[0067] Figure 7 This is the infrared spectrum of PPTU-B3S4 prepared in Example 3;

[0068] Figure 8 This is the 1H NMR spectrum of PPTU-B3S4 prepared in Example 3;

[0069] Figure 9 This is the Raman spectrum of PPTU-B3S4 prepared in Example 3;

[0070] Figure 10 This is the infrared spectrum of the PDA prepared in Example 4;

[0071] Figure 11 This is a schematic diagram of the photo-actuation process of (PETU-B3S4)3-HI-1.0 prepared in Example 5;

[0072] Figure 12 This is a schematic diagram illustrating the application of (PETU-B3S4)3-HI-1.0 prepared in Example 5 in the field of flexible electronic substrates. Detailed Implementation

[0073] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0075] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0076] Source of raw materials

[0077] Isoborneol acrylate (IBOA, AR): Tianjin Xins Biochemical Technology Co., Ltd.

[0078] Hydroxyethyl acrylate (HEA, AR): Tianjin Xins Biochemical Technology Co., Ltd.

[0079] 1,3-Propanedithiol (AR): Tianjin Xins Biochemical Technology Co., Ltd.

[0080] Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO, AR): Huai'an Shuangying Chemical Co., Ltd. Isophorone diisocyanate (IPDI, AR): Anaiji (Shanghai) Pharmaceutical Chemical Co., Ltd.

[0081] Polyethylene Glycol-1000 (PEG-1000, AR): Anaiji (Shanghai) Pharmaceutical Chemicals Co., Ltd.

[0082] Polytetrahydrofuran-1000 (PTMG-1000, AR): Anaiji (Shanghai) Pharmaceutical Chemicals Co., Ltd.

[0083] Polypropylene Glycol-1000 (PPG-1000, AR): Anaiji (Shanghai) Pharmaceutical Chemicals Co., Ltd.

[0084] Butyltin dilaurate (DBTDL, AR): Anaiji (Shanghai) Pharmaceutical Chemical Co., Ltd.

[0085] Tetrahydrofuran (THF, AR): Anaiji (Shanghai) Pharmaceutical Chemicals Co., Ltd.

[0086] Anhydrous methanol (AR, AR): Antech (Shanghai) Pharmaceutical Chemicals Co., Ltd.

[0087] N,N-Dimethylformamide (DMF, AR): Fuchen (Tianjin) Chemical Reagent Co., Ltd.

[0088] 1,4-Butanediol (BDO, AR): Anaiji (Shanghai) Pharmaceutical Chemical Co., Ltd.

[0089] 1,5-Dazabicyclo[4,3,0]-5-nonene (DBN, AR): Anaiji (Shanghai) Pharmaceutical Chemical Co., Ltd. Ammonia (AR): Saen Chemical Technology Co., Ltd.

[0090] Dopamine hydrochloride (DA, AR): Tianjin Xins Biochemical Technology Co., Ltd.

[0091] Anhydrous Ethanol (AR): Antech (Shanghai) Pharmaceutical Chemicals Co., Ltd.

[0092] Nano silver paste: Nanjing Xilit Adhesive Co., Ltd.

[0093] Example 1

[0094] Synthesis of photocurable polyurethane oligomers containing thiocarbamate bonds:

[0095] Step 1: Add 4.44 g (20 mmol) isophorone diisocyanate, 10 g (10 mmol) polyethylene glycol-1000, and 0.02 g dibutyltin dilaurate (DBTDL) to a 250 mL three-necked flask. Then, attach a nitrogen valve, thermometer, and condenser to the three-necked flask, and change the reaction system to a nitrogen atmosphere by evacuating and purging with nitrogen. After heating to 80 °C in an oil bath, react for 4 hours.

[0096] Step 2: Dissolve 0.27 g (3 mmol) of 1,4-butanediol in 20 mL of anhydrous tetrahydrofuran solution, and slowly add it dropwise into a three-necked flask using a syringe to continue the reaction for 4 h.

[0097] Step 3: Dissolve 0.43 g (4 mmol) of 1,3-propanedithiol in 20 mL of anhydrous tetrahydrofuran solution, then add 0.01 g of 1,5-diazabicyclo[4.3.0]-5-nonene catalyst to the tetrahydrofuran solution, and slowly add it dropwise into a three-necked flask using a syringe to continue the reaction for 5 h.

[0098] Step 4: Add 0.696 g (6 mmol) of hydroxyethyl acrylate (HEA) to the system, continue the reaction for 4 h, and remove the tetrahydrofuran solvent to obtain the product PETU-B3S4.

[0099] The reaction formula is as follows:

[0100]

[0101] The infrared spectrum, 1H NMR spectrum, and Raman spectrum of compound PETU-B3S4 are shown in the appendix. Figure 1 Appendix Figure 2 and attached Figure 3 The relevant data is as follows:

[0102] FTIR(KBr,cm -1 )3336(-NHCOS-and-NHCOO-),2954and 2865(-CH3 and-CH2-),1716(-C=O),812(-CH=CH2).

[0103] 1H NMR (400MHz, Chloroform-d) δ6.67-5.90(-OOCCH=CH2),5.40-4.98(-NHCOS-,-NHCOO-),4.32-3.98(-NHCOOCH2-,-O-CH2-CH2-OOCCH=CH2),3.64(-CH2 of PEG-1000,-CH-NHCOO,-CH-NHCOS),3.01-2.77(-CH2-NHCOO,-CH2-NHCOS,-NHCOS-CH2),1.92-1.79(-CH2 ofIPDI,-NHCOOCH2-CH2),1.07-0.86(-CH3 of IPDI).

[0104] The molecular weight test results of compound PETU-B3S4 are as follows: number average molecular weight / Mn: 14052, dispersion index (PDI): 2.46.

[0105] Example 2

[0106] Repeat the steps of Example 1, except that the raw material used in the first step, polyethylene glycol-1000, is replaced with polytetrahydrofuran-1000, and the amount added is 10 mmol (10 g). The reaction formula is as follows:

[0107]

[0108] The infrared spectrum, 1H NMR spectrum, and Raman spectrum of compound PTTU-B3S4 are shown in the appendix. Figure 4 Appendix Figure 5 and attached Figure 6 The relevant data is as follows:

[0109] FTIR(KBr,cm -1 )3331(-NHCOS-and-NHCOO-),2964and 2873(-CH3 and-CH2-),1238(COC),1715(-C=O),810(-CH=CH2).

[0110] 1H NMR (400MHz, Chloroform-d) δ6.50-5.83(-CH=CH2),5.05-4.81(-NHCOO,-NHCOS),4.16-3.80(-NHCOOCH2,-CH2-OOCCH=CH2),3.59-3.32(-O-CH2 of PTMG-1000,-CH-NHCOO,-CH-NHCOS),3.06-2.88(CH2-NHCOO,CH2-NHCOS,-NHCOS-CH2),1.77-1.54(CH2 ofIPDI and PTMG,-NHCOOCH2-CH2),1.11-0.82(-CH3 of IPDI).

[0111] The molecular weight test results of compound PTTU-B3S4 are as follows: number average molecular weight / Mn: 14399, dispersion index (PDI): 2.36.

[0112] Example 3

[0113] Repeat the steps of Example 1, except that the raw material used in the first step, polyethylene glycol-1000, is replaced with polypropylene glycol-1000, and the amount added is 10 mmol (10 g). The reaction formula is as follows:

[0114]

[0115] The infrared spectrum, 1H NMR spectrum, and Raman spectrum of compound PPTU-B3S4 are shown in the appendix. Figure 7 Appendix Figure 8 and attached Figure 9 The relevant data is as follows:

[0116] FTIR(KBr,cm -1 )3335(-NHCOS-and-NHCOO-),2968and 2869(-CH3 and-CH2-),1240(COC),1717(-C=O),813(-CH=CH2).

[0117] 1H NMR (400MHz, Chloroform-d) δ6.48-5.85(-CH=CH2),5.00-4.60(-NHCOO,-NHCOS),4.37-3.92(-NHCOOCH2,-CH2-OOCCH=CH2),3.70-3.29(CH2 and CH of PPG-1000,-CH-NHCOO,-CH-NHCOS),3.01-2.77(CH2-NHCOO,CH2-NHCOS,-NHCOS-CH2),1.89-1.81(CH2 ofIPDI,-NHCOOCH2-CH2),1.27-0.80(-CH3 of IPDI and PPG).

[0118] The molecular weight test results of compound PPTU-B3S4 are as follows: number average molecular weight / Mn: 14829, dispersion index (PDI): 2.42.

[0119] Example 4

[0120] Preparation of polydopamine nanoparticles (PDA):

[0121] Take 2 mL of anhydrous CH3CH2OH, 1 mL of ammonia, and 5 mL of H2O, and mix them together. Then add 0.5 g of dopamine hydrochloride (DA) monomer. The reaction system changes from colorless to dark brown. React at 30 °C for 28 h. After the reaction is complete, centrifuge the solution, and dry the lower solid layer in a vacuum drying oven at 65 °C for 6 h to obtain the product PDA. Its infrared spectrum is shown in the appendix. Figure 10 .

[0122] Example 5

[0123] The purpose of this embodiment is to illustrate that near-infrared responsive self-healing photocurable polyurethane material (PETU-B3S4) 3-HI-1.0 can be prepared using the photocurable polyurethane oligomer PETU-B3S4 containing thiocarbamate bonds prepared in Example 1 and the PDA prepared in Example 5.

[0124] First, weigh out PDA and dissolve it in 10 mL of anhydrous THF. Sonicate for a certain time to ensure uniform dispersion in the THF. After sonication, mix it with PETU-B3S4 oligomer and continue sonicating until the PDA and oligomer are evenly mixed. Then remove the THF. Mix the oligomer with PDA and other monomers such as hydroxyethyl acrylate (HEA), isobornyl acrylate (IBOA), and photoinitiator BAPO to prepare a photosensitive solution. The mass ratio of PETU-B3S4:HEA:IBOA:PDA:BAPO in the photosensitive solution is 60:20:20:1:1. Spread the prepared photosensitive solution evenly on a dumbbell-shaped polytetrafluoroethylene mold. Then cover it with a layer of polyvinyl butyral film to prevent oxygen inhibition from contacting the photosensitive solution with air, which could lead to incomplete curing. Finally, place it under a UV lamp (wavelength 365 nm, light intensity 100 mW cm⁻¹). -2 Near-infrared responsive self-healing photocurable polyurethane material (PETU-B3S4) 3-HI-1.0 was obtained by curing for 20 minutes.

[0125] Cut the self-healing UV-curable material (PETU-B3S4) 3-HI-1.0 in half using a razor blade, then press it with your fingers to bring the broken surfaces into contact, holding for at least 1 minute; then place it in a 1.5W cm -2 The materials were irradiated with a 980nm near-infrared lamp for 30 minutes for repair. The mechanical properties of the initial and repair materials were tested using an electronic materials testing machine. The repair efficiency was calculated by comparing the fracture stress and elongation at break of the repaired sample with those of the initial sample.

[0126] The near-infrared responsive self-healing photocurable polyurethane material (PETU-B3S4) 3-HI-1.0 has an elongation at break of 1021%, a fracture stress of 1.06 MPa, a repair efficiency of 91% for elongation at break, and a repair efficiency of 91% for fracture stress.

[0127] Example 6

[0128] Repeat the steps of Example 5 to prepare near-infrared responsive self-healing photocurable polyurethane material (PTTU-B3S4) 3-HI-1.0. The difference from Example 5 is that “PETU-B3S4” is replaced with “PTTU-B3S4” from Example 2.

[0129] The near-infrared responsive self-healing photocurable polyurethane material (PTTU-B3S4) 3-HI-1.0 has an elongation at break of 1425%, a fracture stress of 1.83 MPa, a repair efficiency of 90% for elongation at break, and a repair efficiency of 91% for fracture stress.

[0130] Example 7

[0131] Repeat the steps of Example 5 to prepare near-infrared responsive self-healing photocurable polyurethane material (PPTU-B3S4) 3-HI-1.0. The difference from Example 5 is that “PETU-B3S4” is replaced with “PPTU-B3S4” from Example 3.

[0132] The near-infrared responsive self-healing photocurable polyurethane material (PPTU-B3S4) 3-HI-1.0 has an elongation at break of 1095%, a fracture stress of 1.01 MPa, a repair efficiency of 90% for both elongation at break and fracture stress.

[0133] Example 8

[0134] The purpose of this embodiment is to demonstrate that the near-infrared photoresponsive self-healing photocurable polyurethane materials prepared in Examples 5, 6, and 7 possess biodegradability. A photocurable film with a mass of m0 was immersed in 20 mL of a mixed solution of methanol and N,N-dimethylformamide containing 0.5 mL of DBN. The film was immersed at 100°C for 0 h, 2 h, 4 h, 6 h, and 7 h, respectively. After drying the residue, its residual mass m was measured. x The degradation rate of the photocurable film at different times was calculated using formula (1). The degradation rates of the self-healing material at different times are shown in Table 1. The data in Table 1 show that the degradation rate of the cured film increases with the increase of immersion time, and it is completely degraded after immersion for 7 hours. This indicates that the cured film has good degradability.

[0135]

[0136] Table 1. Degradation rate of cured film

[0137]

[0138] Example 9

[0139] The purpose of this embodiment is to illustrate that the near-infrared light-responsive self-healing photocurable polyurethane material prepared in Example 5 possesses certain photoactuation properties. We fabricated a dumbbell-shaped material (PETU-B3S4) 3-HI-1.0 with a 50° bending angle through a heating and cooling process. After irradiating it with 980nm NIR light for 10 seconds, the material largely recovered its shape. After irradiation for 60 seconds, the material was almost completely unfolded and restored to its original shape. Based on this function, this type of material can be used in the field of remotely controlled unloading of objects. When a hook loaded with an object is irradiated with near-infrared light for 10 seconds, the material will be activated to unload the object, as shown in the attached diagram. Figure 11 As shown.

[0140] Example 10

[0141] The purpose of this embodiment is to illustrate that the near-infrared photoresponsive self-healing photocurable polyurethane material prepared in Example 5 can be applied to the field of flexible conductive materials. Nano-silver paste was coated onto the prepared sample (PETU-B3S4) 3-HI-1.0 and left at room temperature for 3 hours to cure, thus coating a conductive layer on the material surface. The conductive material was then connected to a battery and an LED light, and its conductivity was verified by the brightness of the bulb. After the circuit was connected, the bulb lit up, indicating that the prepared functionalized material has excellent conductivity. Furthermore, the brightness of the lamp was not affected when the material was rolled or folded, indicating that the material has good flexibility. In addition, after repairing the damaged material, its conductivity and flexibility were not affected; the LED light remained bright even when bent, as shown in the attached figure. Figure 12 As shown.

[0142] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a near-infrared responsive self-healing photocured polyurethane material, characterized in that, The method comprises the following steps: (1) Preparation of polyurethane oligomer containing thio urethane bond: The macromolecular chain extender, catalyst 1 and diisocyanate are heated to react; when the residual amount of -NCO is 50%, the small molecule alcohol chain extender is dissolved in organic solvent 1 and then added dropwise into the reaction system for continuous reaction; then the small molecule mercaptan chain extender and catalyst 2 are dissolved in organic solvent 1 and then added dropwise into the reaction system for continuous reaction; then a blocking agent is added into the reaction system for continuous reaction until the amount of -NCO is 0, and the organic solvent 1 is removed, thereby obtaining the product; the macromolecular chain extender is selected from one or more of polyether diol or polyether polyol with a molecular weight of 200-10000, and polyester diol or polyester polyol with a molecular weight of 1000-10000; (2) Preparation of polydopamine nanoparticles: The organic solvent 2, solvent 3 and deionized water are mixed, then dopamine hydrochloride monomer is added into the mixture, heated to react, centrifuged, and the lower solid is taken out and dried, thereby obtaining the product; (3) The prepared polyurethane oligomer containing thio urethane bond, polydopamine nanoparticles, acrylate monomer and photoinitiator are mixed, and then irradiated with ultraviolet light, thereby obtaining a near-infrared light responsive self-repairing photocuring polyurethane material based on thio urethane bond.

2. The preparation method of the near-infrared responsive self-healing photocurable polyurethane material according to claim 1, characterized in that, The macromolecular chain extender is polyethylene glycol with a molecular weight of 1000-2000.

3. The method of preparing a near-infrared responsive self-healing photo- curable polyurethane material according to claim 1 or 2, characterized in that, The diisocyanate is selected from one or more of 1,6-hexylene diisocyanate, isophorone diisocyanate, trimethyl 1,6-hexylene diisocyanate, hydrogenated 4,4-diphenylmethane diisocyanate, trans-cyclohexane diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, benzylidene diisocyanate, tetramethylxylylene diisocyanate, dicyclohexylmethane diisocyanate and methylcyclohexyl diisocyanate.

4. The preparation method of the near-infrared responsive self-healing photocurable polyurethane material according to claim 3, characterized in that, The small molecule alcohol chain extender is selected from C2-C16 dihydric or polyhydric alcohol; the small molecule mercaptan chain extender is selected from C2-C16 dihydric or polyhydric mercaptan; the catalyst 1 and catalyst 2 are selected from one or more of organic bismuth catalyst, organic tin catalyst and amine catalyst; and the blocking agent is selected from one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

5. The preparation method of the near-infrared responsive self-healing photocurable polyurethane material according to claim 4, characterized in that, The organic solvent 1 is selected from one or more of dimethyl sulfoxide, acetone, dioxane, tetrahydrofuran, methyl formate, methyl ethyl ketone, butyl acetate, propylene glycol methyl ether acetate, ethyl acetate and isopropyl ether; the organic solvent 2 is an alcohol compound; the solvent 3 is an alkaline substance; and the acrylate monomer is one or more of monofunctional, bifunctional or multifunctional acrylate monomer, methacrylate monomer, acrylic acid, acrylamide, methacrylic acid and methacrylamide.

6. The preparation method of the near-infrared responsive self-healing photocurable polyurethane material according to claim 1, characterized in that, In the reaction system of step (1), the ratio of the number of moles of -NCO groups of the isocyanate raw material to the total number of moles of hydroxyl and mercapto groups in the system is 1:

1.

7. The preparation method of the near-infrared responsive self-healing photocurable polyurethane material according to claim 1, characterized in that, The number average molecular weight of the polyurethane oligomer containing a thiourethane bond prepared in the step (1) is 7000-15000; the content of the thiourethane bond in the polyurethane oligomer containing a thiourethane bond is 0.5 wt%-10 wt%.

8. The preparation method of the near-infrared responsive self-healing photocurable polyurethane material according to claim 1, characterized in that, The photoinitiator is selected from one or more of the following: 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-2-methyl-1-phenyl-1-propanone, methyl phenylglyoxylate, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, bis(2,4,6-trimethylbenzoyl) phenyl phosphine oxide.

9. A near-infrared responsive self-healing photo-cured polyurethane material prepared by the method of any one of claims 1-8.

10. Use of the near-infrared responsive self-healing photo-cured polyurethane material of claim 9 in flexible conductive materials and photo-actuated materials.

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