Preparation method of self-repairing polyurethane material based on multiple hydrogen-bond interaction

Abstract

The invention provides a preparation method of a self-repairing polyurethane material based on multiple hydrogen-bond interaction. The preparation method comprises the following steps: firstly, synthesizing acryloyl chloride and glycinamide hydrochloride to obtain acryloyl glycinamide with a bisamide structure; a novel T-shaped chain extender glycyl dihydroxy amine (OH-NAGA-OH) carrying multiple hydrogen bond groups on a side chain is synthesized through the reaction of acryloyl glycyl amide and diethanol amine. The preparation method comprises the following steps: taking polytetrahydrofuran glycol (PTMG) and polydimethylsiloxane (PDMS) as flexible chain segments, taking the flexible chain segments as soft segments of polyurethane, taking isophorone diisocyanate as a hard segment, taking glycyl dihydroxylamine (OH-NAGA-OH) and 2, 6-diaminopyridine (DAP) as chain extenders, and carrying out polymerization reaction according to a molar ratio of PTMG to PDMS to OH-NAGA-OH to DAP of 1: 1: 2: 2, so as to obtain the self-repairing polyurethane material with multiple hydrogen-bond interaction. The polymer has excellent mechanical and self-healing capabilities, and provides more possibilities for application in materials of protective coatings, wearable electronics, flexible electronics, high-end equipment and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high polymer material synthesis, and relates to a preparation method of self-repairing polyurethane based on multiple hydrogen bond action BACKGROUND

[0002] Polyurethane (PU) is a kind of high polymer material with multiple functions, has a wide range of structures and characteristics, can be synthesized by stepwise polymerization of different polyisocyanates and polyols, and the functions of PU can be adjusted by selecting different chain extenders, so that PU is well applied in the fields of elastomers, fibers, foaming materials, adhesives / varnishes, encapsulants and the like. In recent years, self-repairing polyurethane material has been widely valued due to its recyclability and environmental protection effect. The strength of hydrogen bond depends on the properties of donor and acceptor, and due to its directionality, responsiveness and stability, hydrogen bond becomes the most common factor for constructing self-healing PU. Although there are rich hydrogen bond elements in the main chain, the strength of such single hydrogen bond is usually insufficient to enhance and toughen the PU material after healing. Therefore, we build movable hydrogen bond in the side chain to make up for this problem. It is generally believed that there is an inherent paradox between mechanical stiffness and self-healing ability: strong bond leads to increased stiffness, but lower healing efficiency, and weak bond provides effective healing, but produces relatively soft material. In order to solve this contradiction, we design a chain extender, adjust the stiffness and self-healing property of supramolecular PU by introducing soft and hard structures through the chain extender, realize the change of material elasticity by introducing the chain extender, and realize a preparation method of self-repairing polyurethane based on multiple hydrogen bond action through the proportion of soft and hard structures, the introduction of chain extender, and the different structures of polyurethane soft segment and hard segment. SUMMARY

[0003] To this end, the technical problem to be solved by the present application is to provide a preparation method of self-repairing polyurethane based on multiple hydrogen bond action To solve the above technical problem, the present application provides the following technical scheme: A preparation method of self-repairing polyurethane based on multiple hydrogen bond action, comprising the following steps, and the following three items are obtained from the prior art and are not innovative: (1) preparing acryloyl glycine amide ene; (2) synthesizing chain extender glycine dihydroxylamine (OH-NAGA-OH) carrying multiple hydrogen bond groups by addition reaction of acryloyl glycine amide and diethanolamine; (3) preparing polysiloxane urethane prepolymer; (4) adding a mixed solution of glycine dihydroxylamine (OH-NAGA-OH) and 2,6-diaminopyridine dispersed in dimethylformamide into the polysiloxane urethane prepolymer, and obtaining polyurethane polymer with multiple hydrogen bonds after reaction is completed; (5) The polysiloxane urethane film is prepared by solvent casting method, and after vacuum drying, dimethylformamide in the polymer is removed, to obtain the self-repairing polyurethane with multiple hydrogen bonds.

[0004] The above-mentioned preparation method of the self-repairing polyurethane based on multiple hydrogen bonds, in step (1), the preparation of acryloyl glycine amide ene is as follows: (1-1) A three-necked flask with mechanical stirring is added with weighed glycine amide hydrochloride, nitrogen is filled in an ice bath environment, and ice water is added, and it is fully dissolved; (1-2) Ice ether and ice potassium carbonate solution are sequentially added to the flask, and acryloyl chloride dissolved in ether solution is slowly added for reaction; (1-3) After the reaction is completed, hydrochloric acid is added to adjust the pH; (1-4) Extraction, washing of the aqueous phase with ether, adjustment of the pH value to neutral with sodium hydroxide solution, dehydration and drying, washing with ethanol / methanol and drying to obtain the crude product acryloyl glycine amide ene; (1-5) The ethanol / methanol solvent is used for recrystallization, filtration and drying to obtain the pure product acryloyl glycine amide ene.

[0005] The above-mentioned preparation method of the self-repairing polyurethane based on multiple hydrogen bonds, In step (1-1), the addition amount of glycine amide hydrochloride is 6.3-10.3 g, and the ice water is 6-10 ml.

[0006] In step (1-2), the addition amount of ice ether is 16-22 mL, the addition amount of ice potassium carbonate solution is 32-38 mL, the molar concentration of ice potassium carbonate is 2-4 M, the addition amount of solvent ether solution is 22-30 ml, the addition amount of acryloyl chloride is 5-10 g, the reaction time is 2-4 hours, and the reaction temperature is room temperature.

[0007] In step (1-3), the molar concentration of hydrochloric acid solution is 6-8 M, and the pH is adjusted to 2-3.

[0008] In step (1-4), the extraction removes the organic phase, the molar concentration of sodium hydroxide solution is 2-3 M, and the volume ratio of ethanol to methanol in the ethanol / methanol mixed solution is 4:1.

[0009] In step (1-5), the volume ratio of ethanol to methanol in the ethanol / methanol mixed solution is 4:1, and the recrystallization temperature is 120-130℃.

[0010] The above-mentioned preparation method of the self-repairing polyurethane based on multiple hydrogen bonds, in step (2), the preparation of acryloyl glycine amide and diethanol amine addition reaction to synthesize the chain extender glycine dihydroxy amine (OH-NAGA-OH) carrying multiple hydrogen bond groups is as follows: (2-1) Dissolve acryloyl glycine amide in a mixed solvent of deionized water and methanol; (2-2) Further add diethanolamine dispersed in a methanol solution dropwise thereto, and stir until the reaction is completed; (2-3) Evaporate the solvent, wash the remaining solid until the pH value reaches neutral, and vacuum dry to obtain a light brown oily product, glycine dihydroxylamine (OH-NAGA-OH) carrying multiple hydrogen bonding groups.

[0011] The above preparation method of a self-repairing polyurethane based on multiple hydrogen bonding, In step (2-1), the amount of acryloyl glycine amide added is 10-12 g; In step (2-2), the amount of methanol solution added as a solvent is 18-20 ml, the amount of diethanolamine added is 7-10 g, the reaction temperature is 40-42°C, and the stirring reaction time is 15-24 h; In step (2-3), the washing liquid is acetone, and the vacuum drying time is 1-2 h.

[0012] The above preparation method of an acryloyl glycine amide self-repairing polyurethane based on multiple hydrogen bonding, in step (3), the preparation method of the polysiloxane urethane prepolymer is as follows: (3-1) Vacuum heat and mechanically stir polytetrahydrofuran diol and polydimethylsiloxane in a 100 mL three-neck glass flask to remove water.

[0013] (3-2) After water removal, add an appropriate amount of isophorone diisocyanate and a catalyst dibutyltin dilaurate to the molten polyoxyfuran diol, and fully stir and react under a nitrogen atmosphere to obtain a polyurethane prepolymer.

[0014] The above preparation method of a self-repairing polyurethane based on multiple hydrogen bonding, In step (3-1), the amount of polytetrahydrofuran diol and polydimethylsiloxane added is 1.5-3 g, the vacuum heating temperature is 100-120°C, and the mechanical stirring time is 2-3 h.

[0015] In step (3-2), the temperature to be reduced is 65-70°C, the amount of catalyst dibutyltin dilaurate added is 1-2 drops, the reaction temperature is 70-75°C, and the stirring time is 3-4 h.

[0016] The preparation method of the self-repairing polyurethane based on multiple hydrogen bond effects has the following steps: (1) preparing a polyurethane prepolymer; (2) preparing a polyurethane prepolymer by mixing the polyurethane prepolymer with a chain extender; (3) preparing a polyurethane prepolymer by mixing the polyurethane prepolymer with a chain extender; (4) adding a mixed solution of glycyl dihydroxylamine (OH-NAGA-OH) and 2,6-diaminopyridine into the polysiloxane urethane prepolymer, and obtaining the polyurethane polymer with multiple hydrogen bonds after the reaction is completed; and (5) preparing a polysiloxane urethane film by using a solvent casting method, and removing dimethylformamide in the polymer after vacuum drying, so that the self-repairing polyurethane based on multiple hydrogen bond effects is obtained.

[0017] The preparation method of the self-repairing polyurethane based on multiple hydrogen bond effects has the following steps: (1) preparing a polyurethane prepolymer; (2) preparing a polyurethane prepolymer by mixing the polyurethane prepolymer with a chain extender; (3) preparing a polyurethane prepolymer by mixing the polyurethane prepolymer with a chain extender; (4) adding a mixed solution of glycyl dihydroxylamine (OH-NAGA-OH) and 2,6-diaminopyridine into the polysiloxane urethane prepolymer, and obtaining the polyurethane polymer with multiple hydrogen bonds after the reaction is completed; and (5) preparing a polysiloxane urethane film by using a solvent casting method, and removing dimethylformamide in the polymer after vacuum drying, so that the self-repairing polyurethane based on multiple hydrogen bond effects is obtained. In step (4), the reaction time is 2-3 h, and the reaction temperature is 80-90 DEG C. In step (5), the drying temperature is 70-80 DEG C, and the drying time is 45-50 h.

[0018] The technical scheme of the present application has the following beneficial technical effects: It is generally believed that there is an inherent paradox between mechanical stiffness and self-healing ability: strong bonds lead to increased stiffness, but lower healing efficiency, and weak bonds provide effective healing, but produce a relatively soft material. After consulting relevant information, the applicant conceives and designs a chain extender, which adjusts the stiffness and self-healing property of the supramolecular PU by introducing a soft-hard structure through the chain extender, and prepares a high-hardness supramolecular polyurethane material with self-repairing at room temperature based on hydrogen bonds.

[0019] After the applicant conducts relevant experimental research, a preparation method of self-repairing polyurethane based on multiple hydrogen bond effects is successfully invented.

[0020] According to experimental tests, the self-repairing polyurethane amine based on multiple hydrogen bond effects can obtain good mechanical properties while ensuring self-repairing performance.

[0021] According to the component proportions of polytetrahydrofuran diol (PTMG), polydimethylsiloxane (PDMS), acryloyl glycine amide (NAGA) and 2,6-diaminopyridine (DAP), two acryloyl glycine amides (PNADA-Si) are prepared, and the acryloyl glycine amide with the best effect is named as PNADA-Si, which is a self-repairing polyurethane based on multiple hydrogen bond effects. 0.5 The subscript represents the molar ratio of the acryloyl glycine amide chain extender (OH-NAGA-OH) to the 2,6-diaminopyridine (DAP). DETAILED DESCRIPTION

[0023] Figure 1 The preparation schematic diagram of PNADA-Si is shown in FIG. 1.

[0024] Figure 2 PNADA11-Si, PNADA 0.5 Fourier infrared test spectrum of PNADA11-Si, PNADA

[0025] Figure 3 PNADA11-Si, PNADA 0.5 Stress-strain curve in tensile test of PNADA11-Si, PNADA

[0026] Figure 4 PNADA11-Si, PNADA 0.5 Ultimate stress curve of PNADA11-Si, PNADA

[0027] Figure 5 PNADA11-Si, PNADA 0.5 Ultimate strain curve of PNADA11-Si, PNADA

[0028] Figure 6 Scratch test of PNADA11-Si, PNADA 0.5 Self-repairing process of PNADA11-Si, PNADA

[0029] Figure 7 PNADA11-Si, PNADA 0.5 Remaining weight of PNADA11-Si, PNADA after soaking in deionized water for 24 h

[0030] DETAILED DESCRIPTION: A preparation method of a self-repairing polyurethane based on multiple hydrogen bonding

[0031] The preparation method of the acryloyl glycine amide self-repairing polyurethane based on multiple hydrogen bonding in the embodiment comprises the following steps: (1) Preparation of acryloyl glycine amide ene; (2) Addition reaction of acryloyl glycine amide and diethanolamine to synthesize chain extender glycine dihydroxylamine (OH-NAGA-OH) carrying multiple hydrogen bonding groups; (3) Preparation of polysiloxane urethane prepolymer prepolymer; (4) The mixed solution of glycine dihydroxylamine (OH-NAGA-OH) and 2,6-diaminopyridine dispersed in dimethylformamide is added to the polysiloxane urethane prepolymer, and the polyurethane polymer with multiple hydrogen bonds is obtained after the reaction is completed; (5) The polysiloxane urethane prepolymer film is prepared by solvent casting method, and the dimethylformamide in the polymer is removed after vacuum drying, and the poly multiple hydrogen bond self-repairing polyurethane polymer is obtained.

[0032] The preparation method of the self-repairing polyurethane based on multiple hydrogen bonding described above, in step (1), the preparation method of acryloyl glycine amide ene is as follows: (1-1) Add the weighed glycine amide hydrochloride to a three-necked flask equipped with mechanical stirring, fill with nitrogen in an ice bath environment, and add ice water to dissolve it thoroughly; (1-2) Add ice ether and ice potassium carbonate solution to the flask in sequence, and then slowly add the acryloyl chloride dissolved in ether solution to react; (1-3) After the reaction is complete, add hydrochloric acid to adjust the pH; (1-4) Extract, wash the aqueous phase with ether, then adjust the pH to neutral with sodium hydroxide solution, dehydrate and dry. Wash with ethanol / methanol and dry to obtain the crude product acryloyl glycine amide ene; (1-5) The ethanol / methanol solvent is used to recrystallize, filter and dry to obtain the pure product acryloyl glycine amide ene.

[0033] The above-mentioned preparation method of a self-repairing polyurethane based on multiple hydrogen bonding, In step (1-1), the amount of glycine amide hydrochloride added is 6.3-10.3 g, and the amount of ice water is 6-10 ml In step (1-2), the amount of ice ether added is 16-22 mL, the amount of ice potassium carbonate solution added is 32-38 mL, the molar concentration of ice potassium carbonate is 2-4 M, the amount of solvent ether solution added is 22-30 ml, the amount of acryloyl chloride added is 5-10 g, the reaction time is 2-4 hours, and the reaction temperature is room temperature.

[0034] In step (1-3), the molar concentration of the hydrochloric acid solution is 6-8 M, and the pH is adjusted to 2-3.

[0035] In step (1-4), the organic phase is removed by extraction, the molar concentration of the sodium hydroxide solution is 2-3 M, and the volume ratio of ethanol to methanol in the ethanol / methanol mixed solution is 4:1.

[0036] In step (1-5), the volume ratio of ethanol to methanol in the ethanol / methanol mixed solution is 4:1, and the recrystallization temperature is 120-130°C.

[0037] The above-mentioned preparation method of a self-repairing polyurethane based on multiple hydrogen bonding, in step (2), the method for preparing the glycine amide acryloyl and diethanolamine addition reaction to synthesize the chain extender glycine dihydroxy amine (OH-NAGA-OH) carrying multiple hydrogen bonding groups is as follows: (2-1) Dissolve the acryloyl glycine amide in a mixed solvent of deionized water and methanol; (2-2) Then add diethanolamine dispersed in methanol solution dropwise, and stir until the reaction is complete; (2-3) Evaporate the solvent, wash the remaining solid until the pH value reaches neutral, and vacuum dry to obtain a light brown oily product, glycyl dihydroxylamine (OH-NAGA-OH) carrying multiple hydrogen bonding groups.

[0038] The above method for preparing a self-repairing polyurethane based on multiple hydrogen bonding, In step (2-1), the acryloyl glycine amide is added in an amount of 10-12 g. In step (2-2), the methanol solution as the solvent is added in an amount of 18-20 ml, diethanolamine is added in an amount of 7-10 g, the reaction temperature is 40-42°C, and the stirring reaction time is 15-24 h. In step (2-3), the washing liquid is acetone, and the vacuum drying time is 1-2 h.

[0039] In step (3) of the above method for preparing a self-repairing polyurethane based on multiple hydrogen bonding, the polyurethane prepolymer is prepared as follows: (3-1) The polytetrahydrofuran diol and the polydimethylsiloxane are vacuum heated and mechanically stirred to remove water in a 100 mL three-neck glass flask.

[0040] (3-2) After water removal, an appropriate amount of isophorone diisocyanate and a catalyst dibutyltin dilaurate are added to the molten polyoxyfuran diol, and after fully stirring and reacting under a nitrogen atmosphere, a polyurethane prepolymer is obtained.

[0041] The above method for preparing a self-repairing polyurethane based on multiple hydrogen bonding, In step (3-1), the polytetrahydrofuran diol and the polydimethylsiloxane are added in an amount of 1.5-3 g, vacuum heating is performed at a temperature of 100-120°C, and mechanical stirring is performed for 2-3 h.

[0042] In step (3-2), the temperature is lowered to 65-70°C, the catalyst dibutyltin dilaurate is added in an amount of 1-2 drops, the reaction temperature is 70-75°C, and the stirring time is 3-4 h.

[0043] In step (4) of the above method for preparing a self-repairing polyurethane based on multiple hydrogen bonding, a mixed solution of glycyl dihydroxylamine (OH-NAGA-OH) and 2,6-diaminopyridine dispersed in dimethylformamide is added to the polysiloxane urethane prepolymer prepolymer, and after the reaction is completed, a self-repairing polyurethane polymer with multiple hydrogen bonding is obtained. In step (5), a polysiloxane urethane film is prepared by a solvent casting method, and after vacuum drying, dimethylformamide is removed from the polymer, and a self-repairing polyurethane based on multiple hydrogen bonding is obtained.

[0044] The preparation method of the self-repairing polyurethane based on multiple hydrogen bonds, The reaction time in step (4) is 2-3 h, and the reaction temperature is 80-90 °C. The drying temperature in step (5) is 70-80 °C, and the drying time is 45-50 h.

[0045] Results and characterization

[0046] (1) Fourier infrared test spectrum characterization of PNADA1-Si, PNADA 0.5 -Si As Figure 2 shown, Fourier infrared test was performed on the synthesized polyurethane self-repairing material PNADA1PNADA 0.5 -Si. From the FTIR spectrum, it can be seen that the absorption bands at 3300 and 1540 cm−1 are caused by the stretching and bending vibration of N-H. The stretching vibration region of C=O group is divided into two peaks at 1693 and 1647 cm−1, which belong to free C=O group and hydrogen-bonded C=O group, respectively. The absorption peaks are 2935 cm−1 and 2850 cm−1, which are the absorption peaks of the methyl groups in IPDI. In the characteristic spectrum of PNADA-Si, Si-O characteristic peaks appear at 1080 cm−1 and 800 cm−1, indicating that polydimethylsiloxane is introduced into the polyurethane as a soft segment to adjust the hardness of the main chain. There is no characteristic peak of -NCO at 2260 ~ 2280 cm−1, which proves that the -NCO of IPDI has completely reacted with -OH and -NH to form polyurethane.

[0047] (2) Mechanical properties As Figure 3 shown, the stress-strain curves of PNADA1-Si, PNADA 0.5 -Si in tensile test, the performance of PNADA1-Si is better. As Figure 4 , Five shown, the ultimate stress and strain curves of PNADA1-Si, PNADA 0.5 -Si in tensile test, combined with Figure 3 , PNADA1PNADA 0.5 Although the strain capacity is not very good, the ultimate stress is increased, which is mainly because the structure of PDMS contains more methylene groups, which makes it have greater flexibility and better intermolecular force, thereby improving the mechanical properties of the material.

[0048] (3) Self-repairing performance As Figure 6 shown, after the scratch test, the digital camera was used to take pictures of PNADA1PNADA0.5 The self-healing process was imaged (×10). To further investigate the effect of temperature on the self-healing of polyurethane materials, the materials were placed in a 50℃ oven for further repair. After 2 hours, the cracks in PNADA1-Si and PNADA0.5-Si did not show significant changes. Therefore, these two materials were placed in a 100℃ oven. After 2 hours, the scratches on PNADA1-Si disappeared significantly, but those on PNADA0.5-Si... 0.5 -Si cracks are more pronounced, therefore PNADA1-Si exhibits significant high-temperature self-healing ability. 0.5 -Si does not have self-healing capabilities.

[0049] (4) Swelling performance analysis like Figure 7 As shown, PNADA1-Si, PNADA 0.5 -Si remained undissolved at room temperature for 24 hours, with only a very small amount of solvent entering the polymer cross-linked network structure. In comparison, PNADA1-Si exhibits better solvent resistance, indicating that the hydrogen bonds introduced into the DAP backbone increase the degree of polymer cross-linking, thereby improving the material's solvent resistance. PNADA 0.5 After being completely immersed in water for 24 hours, the sample can still be obtained relatively intact after being removed and the solvent removed. The introduction of DAP improves the cross-linking degree of the material, ensuring that the material can have higher mechanical strength and hardness.

[0050] In summary, PNADA1-Si exhibits the best performance in terms of hydrogen bond characterization, mechanical properties, self-healing properties, and swelling properties.

[0051] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for preparing a self-healing polyurethane material based on multiple hydrogen bonding interactions, characterized in that, Includes the following steps; (1) Disperse glycyl dihydroxyamine (OH-NAGA-OH) in dimethylformamide: (2) A mixed solution of glycyl dihydroxyamine (OH-NAGA-OH) and 2,6-diaminopyridine dispersed in dimethylformamide was added to a polyurethane prepolymer, and the reaction was carried out to obtain a polyurethane polymer with multiple hydrogen bonds. (3) A polyurethane membrane was prepared by solvent casting. After vacuum drying, dimethylformamide in the polymer was removed to obtain a self-healing polyurethane based on multiple hydrogen bonding.

2. The method for preparing a self-healing polyurethane material based on multiple hydrogen bonding according to claim 1, characterized in that, In step (2), 2,6-diaminopyridine is introduced as an amplification chain and mixed with glycine dihydroxyamine (OH-NAGA-OH) dispersed in dimethylformamide and added to the polyurethane prepolymer to react and obtain a polyurethane polymer with multiple hydrogen bonds.

3. In step (2), the self-healing polyurethane is represented as PNADA11-Si and PNADA. 0.5 -Si, where Si represents silicone-containing polyurethane, P represents polydimethylsiloxane (PDMS), NA represents acryloylglycine chain extender (OH-NAGA-OH), DA represents 2,6-diaminopyridine, and the subscripts indicate the molar ratio of acryloylglycine chain extender (OH-NAGA-OH) to 2,6-diaminopyridine (DAP). The reaction time is 2–3 h, and the reaction temperature is 70–90 °C.

4. The method for preparing a self-healing polyurethane material based on multiple hydrogen bonding according to claim 1, characterized in that, In step (3) The drying temperature is 70-80℃, and the drying time is 45-50h.

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