Photocured mussel-biomimetic acylhydrazone, preparation method and application thereof

Abstract

The application discloses a kind of photo-curing mussel biomimetic acylhydrazone and its preparation method and application, the structural formula of the photo-curing mussel biomimetic acylhydrazone is as shown in formula (I).The photo-curing mussel biomimetic acylhydrazone of the application has catechol structure and carbon-carbon double bond, raw material is low in price, synthesis process does not need to modify catechol structure, preparation method is simple, can reduce the synthesis difficulty and production cost of mussel biomimetic material.The mussel biomimetic photo-curing adhesive composition prepared by using photo-curing mussel biomimetic acylhydrazone as raw material has good adhesive property, and can improve the problem of insufficient adhesion and failure of photo-curing adhesive, and prevent falling.

Description

Technical Field

[0001] The invention belongs to the technical field of light-curing materials, and in particular relates to light-curing mussel biomimetic acylhydrazone and a preparation method and application thereof. Background Art

[0002] Marine mussels secrete a fast-setting, waterproof adhesive protein called mucus, which allows them to firmly adhere to various substrates, including metal, glass, polymers, and minerals. Research has found that this is due to the presence of large amounts of 3,4-dihydroxyphenylalanine (DOPA) and dopamine (DA) in the adhesive protein. Both DOPA and dopamine contain a catechol structure, which allows for excellent adhesion to substrates. Currently, light-curing adhesives generally suffer from insufficient adhesion and sometimes fail, leading to shedding. Therefore, mussel-inspired materials, which may be able to address these issues, have become a research hotspot.

[0003] However, existing mussel biomimetic materials generally use dopamine as a raw material for chemical modification. On the one hand, dopamine is expensive, which limits the development and application of mussel biomimetic materials. On the other hand, the chemical properties of the catechol structure are active and easily oxidized to quinones under heating or alkaline conditions. Therefore, mussel biomimetic materials need to protect and deprotect the catechol structure, which increases the difficulty of synthesis and production costs. Therefore, it is of research significance to find mussel biomimetic materials with a catechol structure that has stable chemical properties, cheap raw materials, and does not require chemical protection for synthesis. Summary of the Invention

[0004] The first object of the present invention is to provide a photocurable mussel biomimetic acylhydrazone to solve at least one of the above problems.

[0005] The second object of the present invention is to provide a method for preparing a photocurable mussel biomimetic acylhydrazone to solve at least one of the above problems.

[0006] The third object of the present invention is to provide an application of a photocurable mussel biomimetic acylhydrazone in a mussel biomimetic photocurable adhesive composition to solve at least one of the above problems.

[0007] A fourth object of the present invention is to provide a mussel biomimetic light-curing adhesive composition to solve at least one of the above problems.

[0008] A fifth object of the present invention is to provide a method for preparing a mussel biomimetic light-curing adhesive composition to solve at least one of the above problems.

[0009] In a first aspect, the present invention provides a photocurable mussel biomimetic acylhydrazone, wherein the photocurable mussel biomimetic acylhydrazone has a structural formula as shown in formula (I):

[0010]

[0011] The light-cured mussel biomimetic acylhydrazone is prepared by using vanillin methyl methacrylate and protocatechuic acid benzoyl hydrazide through Schiff base reaction.

[0012] The light-cured mussel biomimetic acylhydrazone according to the present invention has a molecular structure that has both a catechol structure that simulates mussel protein and a carbon-carbon double bond that can participate in curing, and is a new type of mussel biomimetic material.

[0013] In a second aspect, the present invention provides a method for preparing a photocurable mussel biomimetic acylhydrazone, the method comprising the following steps:

[0014] Dissolve vanillin methyl methacrylate and protocatechu benzoyl hydrazide in an organic solvent, add acetic acid in a nitrogen atmosphere, react at 50-80° C. for 1-4 hours, then purify and dry to obtain the product.

[0015] According to the preparation method of the light-cured mussel biomimetic acylhydrazone of the present invention, vanillin methyl methacrylate and protocatechu benzoyl hydrazide undergo a Schiff base reaction to synthesize the light-cured mussel biomimetic acylhydrazone (MH-VM). The synthesis process does not require protection and deprotection of the catechol structure, the preparation method is simple, and the synthesis difficulty and production cost of the mussel biomimetic material are reduced.

[0016] In some embodiments, the molar ratio of vanillin methyl methacrylate to protocatechuic acid benzoyl hydrazide may be 1:(0.9-1.3).

[0017] In some embodiments, the organic solvent is selected from at least one of methanol and anhydrous ethanol.

[0018] In some embodiments, the amount of acetic acid used can be 2-5% of the total mass of the reaction system (ie, the total mass of vanillin methyl methacrylate, protocatechubenzohydrazide and acetic acid).

[0019] In some embodiments, the purification process may include cooling to room temperature, filtering, and washing the solid with an organic solvent until it becomes neutral. Specifically, the organic solvent is selected from at least one of methanol and anhydrous ethanol.

[0020] In other embodiments, the purification method can be cooling to room temperature, filtering, and then washing the solid with anhydrous ethanol pre-cooled at 5° C. until the solid is neutral. Using pre-cooled anhydrous ethanol to wash the solid can increase the yield of the product.

[0021] In some embodiments, the drying treatment method may be to dry the purified solid in a vacuum atmosphere at 25 to 45° C. for 20 to 48 hours.

[0022] In some embodiments, the method for preparing vanillin methyl methacrylate comprises the following steps:

[0023] Mix vanillin, methacrylic anhydride and 4-dimethylaminopyridine, react at 50-80° C. for 24-48 hours in a nitrogen atmosphere, then purify and dry to obtain the product.

[0024] In some embodiments, the molar ratio of vanillin to methacrylic anhydride may be 1:(1.1-2.0).

[0025] In some embodiments, the amount of 4-dimethylaminopyridine used is 0.2-1% of the total mass of the reaction system (ie, the total mass of vanillin, methacrylic anhydride and 4-dimethylaminopyridine).

[0026] In some embodiments, the purification treatment method can be to first cool to room temperature, add a diluent to the reaction system, first wash with a saturated NaHCO3 solution, then wash with a 0.5 mol / L NaOH solution and a 1 mol / L NaOH solution 2 to 5 times each, and finally wash with deionized water 2 to 5 times.

[0027] In other embodiments, the diluent may be selected from at least one of dichloromethane and chloroform.

[0028] In other embodiments, the amount of the diluent used may be 50-90% of the total mass of the reaction system (ie, the total mass of vanillin, methacrylic anhydride, and 4-dimethylaminopyridine).

[0029] In other embodiments, the volumes of the saturated NaHCO 3 solution, the 0.5 mol / L NaOH solution, and the 1 mol / L NaOH solution may be 150 to 300 mL.

[0030] In some embodiments, the drying treatment method can be to first collect the purified organic phase, dry it with anhydrous magnesium sulfate, concentrate it, and then dry it in a vacuum atmosphere at 25 to 45° C. for 12 to 36 hours.

[0031] In some embodiments, the preparation method of protocatechu benzoyl hydrazide comprises the following steps:

[0032] Dissolve methyl 3,4-dihydroxybenzoate in an organic solvent, add hydrazine hydrate solution in a nitrogen atmosphere, react at 25-80°C for 2-24 hours, then purify and dry to obtain the product.

[0033] In some embodiments, the organic solvent is selected from at least one of methanol and anhydrous ethanol.

[0034] In some embodiments, the molar ratio of methyl 3,4-dihydroxybenzoate to hydrazine hydrate is 1:(1.0-2).

[0035] In some embodiments, the mass fraction of hydrazine hydrate in the hydrazine hydrate solution may be 70 to 90%.

[0036] In some embodiments, the purification process may include cooling to room temperature, filtering, and washing the solid with an organic solvent until it becomes neutral. Specifically, the organic solvent is selected from at least one of methanol and anhydrous ethanol.

[0037] In some embodiments, the drying treatment method may be to dry the purified solid in a vacuum atmosphere at 25-40° C. for 24-48 hours.

[0038] In a third aspect, the present invention provides the use of a photocurable mussel biomimetic acylhydrazone in a mussel biomimetic photocurable adhesive composition.

[0039] Specifically, the photocurable mussel biomimetic acylhydrazone of the present invention has both the catechol structure, the main chemical structure of mussel adhesion, and a carbon-carbon double bond that can undergo photopolymerization reaction with the resin matrix. It can be used to prepare a photocurable adhesive composition to solve the problems of insufficient bonding ability of photocurable adhesives and shedding due to failure.

[0040] In a fourth aspect, the present invention provides a mussel biomimetic photocurable adhesive composition, which is prepared from a reaction system of a resin matrix, a solvent, a photoinitiator, and the above-mentioned photocurable mussel biomimetic acylhydrazone;

[0041] Among them, the mass of the resin matrix can be 50% to 80% of the total mass of the reaction system, the mass of the solvent can be 10% to 20% of the total mass of the reaction system, the mass of the photoinitiator can be 4% to 6% of the total mass of the reaction system, and the mass of the photocurable mussel biomimetic acylhydrazone can be 1% to 30% of the total mass of the reaction system.

[0042] In some embodiments, the resin matrix may be polyethylene glycol dimethacrylate, and the number average molecular weight of the polyethylene glycol dimethacrylate is 360-1000.

[0043] In some embodiments, the solvent may be selected from at least one of dimethyl sulfoxide, tetrahydrofuran, and N,N-dimethylformamide.

[0044] In some embodiments, the photoinitiator can be a free radical photoinitiator.

[0045] In other embodiments, the photoinitiator may be selected from at least one of PI-1173, PI-2959, and TPO.

[0046] In some embodiments, the mussel biomimetic light-curable adhesive composition may be cured by placing the mussel biomimetic light-curable adhesive composition under ultraviolet light with a wavelength of 365 to 405 nm for ultraviolet light curing for 60 to 600 seconds.

[0047] In a fifth aspect, the present invention provides a method for preparing a mussel biomimetic photocurable adhesive composition, which comprises dissolving a photocurable mussel biomimetic acylhydrazone in a solvent, adding a resin matrix and a photoinitiator, and mixing them uniformly to obtain the composition.

[0048] The beneficial effects of the present invention are:

[0049] (1) The photocurable mussel biomimetic acylhydrazone of the present invention has low raw material cost; its molecular structure has both a catechol structure that simulates mussel adhesion and a carbon-carbon double bond that can participate in photocuring, and can be used as a new mussel biomimetic material;

[0050] (2) The preparation method of the photocurable mussel biomimetic acylhydrazone of the present invention does not require protection and deprotection of the catechol structure during the synthesis process, and the preparation method is simple, which reduces the synthesis difficulty and production cost of the mussel biomimetic material;

[0051] (3) The mussel biomimetic photocurable adhesive composition prepared by using photocurable mussel biomimetic acylhydrazone as raw material has good adhesive properties and can improve the problem of insufficient adhesion and failure of photocurable adhesives leading to shedding. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The synthetic route of the photocurable mussel biomimetic acylhydrazone of the present invention is as follows;

[0053] Figure 2 IR spectra of VA and VA-MA of Example 3 of the present invention;

[0054] Figure 3 1H NMR spectra of VA and VA-MA of Example 3 of the present invention;

[0055] Figure 4 IR spectra of MD and MD-HH of Example 3 of the present invention;

[0056] Figure 5 1H NMR spectra of MD and MD-HH of Example 3 of the present invention;

[0057] Figure 6 This is a comparison of infrared spectra of VA-MA, MD-HH and MH-VM of Example 3 of the present invention;

[0058] Figure 7 This is the hydrogen nuclear magnetic resonance spectrum of MH-VM of Example 3 of the present invention;

[0059] Figure 8 The differential scanning calorimetry test results of the mussel biomimetic light-curing adhesive compositions of Examples 4-6 of the present invention and the light-curing adhesive composition of Comparative Example 1 are shown;

[0060] Figure 9 Schematic diagram of sample preparation for adhesion performance test of Experimental Example 2 of the present invention;

[0061] Figure 10 These are the test results of the adhesive properties of the mussel biomimetic light-curing adhesive compositions of Examples 4-6 of the present invention and the light-curing adhesive composition of Comparative Example 1;

[0062] Figure 11 (a) is the TGA curve of the cured films of the mussel biomimetic photocurable adhesive compositions of Examples 4-6 of the present invention and the photocurable adhesive composition of Comparative Example 1, Figure 11 (b) DTG curves of the cured films of the mussel biomimetic photocurable adhesive compositions of Examples 4-6 of the present invention and the photocurable adhesive composition of Comparative Example 1;

[0063] Figure 12 (a) is an infrared absorption peak diagram of the main functional groups of the mussel biomimetic photocurable adhesive compositions of Examples 4-6 of the present invention and the photocurable adhesive composition of Comparative Example 1 before curing, Figure 12 (b) is an infrared absorption peak diagram of the main functional groups of the mussel biomimetic photocurable adhesive compositions of Examples 4-6 of the present invention and the photocurable adhesive composition of Comparative Example 1 after curing. DETAILED DESCRIPTION

[0064] The present invention will be further described in detail below with reference to the following embodiments. The examples are provided for illustrative purposes only and are not intended to limit the present invention in any way. Unless otherwise specified, the raw materials and reagents used in the examples are commercially available conventional products. Experimental procedures in the examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer.

[0065] The synthetic route of the photocurable mussel biomimetic acylhydrazone (MH-VM) of Examples 1-3 of the present invention is as follows: Figure 1 shown.

[0066] Example 1

[0067] This embodiment provides a method for preparing a photocurable mussel biomimetic acylhydrazone, comprising the following steps:

[0068] To a 250 mL three-necked flask equipped with a mechanical stirring device and a condenser, 30 g of vanillin (0.20 mol), 45 g of methacrylic anhydride (0.29 mol) and 0.6 g of 4-dimethylaminopyridine were added. After nitrogen was introduced into the three-necked flask to expel oxygen, the mixture was stirred for 48 h under a nitrogen atmosphere and a temperature of 80 ° C., then cooled to room temperature, 150 mL of dichloromethane was added and the mixture was transferred to a separatory funnel. The mixture was first washed with 300 mL of saturated NaHCO3 solution until no bubbles were generated in the mixture, and then washed 3 times with 300 mL of 0.5 mol / L NaOH solution and 300 mL of 1 mol / L NaOH solution, respectively, and finally washed 3 times with deionized water. The organic phase was collected and dried over anhydrous magnesium sulfate overnight. The organic phase was concentrated with a rotary evaporator and the concentrated organic phase was transferred to a glass Petri dish. The glass Petri dish was placed in a vacuum oven at 25 ° C. and vacuum dried for 36 h to obtain a first intermediate product as a white solid.

[0069] To a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser, 16.8 g of methyl 3,4-dihydroxybenzoate (0.10 mol) and 200 mL of anhydrous ethanol were added, and the mixture was stirred for 15 minutes until the methyl 3,4-dihydroxybenzoate was dissolved in the anhydrous ethanol. Nitrogen was introduced into the three-necked flask to expel oxygen, and 11.01 g of a hydrazine hydrate solution (0.18 mol) with a mass fraction of 80% was added. The temperature was raised to 50 ° C. and the reaction was carried out for 18 hours. The mixture was then cooled to room temperature and filtered. The solid was washed with anhydrous ethanol until neutral, and then the solid was placed in a vacuum oven and vacuum dried at 25 ° C. for 36 hours to obtain a second intermediate product as a white powder;

[0070] To a 250 mL three-necked flask equipped with a mechanical stirring device and a condenser, 3.5 g of the first intermediate product (0.016 mol), 3 g of the second intermediate product (0.018 mol) and 20 mL of anhydrous ethanol were added. After nitrogen was introduced into the three-necked flask to expel oxygen, 0.1950 g of acetic acid was added dropwise. The mixture was reacted under a nitrogen atmosphere and a temperature of 65 ° C for 3.5 h, then cooled to room temperature, filtered and washed with anhydrous ethanol, and then placed in a vacuum oven and vacuum dried at 35 ° C for 48 h to obtain a white powder product.

[0071] Example 2

[0072] This embodiment provides a method for preparing a photocurable mussel biomimetic acylhydrazone, comprising the following steps:

[0073] To a 250 mL three-necked flask equipped with a mechanical stirrer, 30 g of vanillin (0.20 mol), 61 g of methacrylic anhydride (0.40 mol) and 0.9 g of 4-dimethylaminopyridine were added. After nitrogen was introduced into the three-necked flask to expel oxygen, the mixture was stirred for 24 h under a nitrogen atmosphere at 60 ° C., then cooled to room temperature, 150 mL of dichloromethane was added and the mixture was transferred to a separatory funnel. The mixture was first washed with 500 mL of saturated NaHCO3 solution until no bubbles were generated, and then washed with 500 mL of 0.5 mol / L NaOH solution and 500 mL of 1 mol / L NaOH solution three times each, and finally washed with deionized water three times. The organic phase was collected and dried over anhydrous magnesium sulfate overnight. The organic phase was concentrated using a rotary evaporator and the concentrated organic phase was transferred to a glass Petri dish. The glass Petri dish was placed in a vacuum oven at 40 ° C. and vacuum dried for 12 h to obtain a first intermediate product as a white solid.

[0074] To a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser, 16.8 g of methyl 3,4-dihydroxybenzoate (0.1 mol) and 200 mL of anhydrous ethanol were added, and the mixture was stirred for 15 minutes until the methyl 3,4-dihydroxybenzoate was dissolved in the anhydrous ethanol. Nitrogen was introduced into the three-necked flask to expel oxygen, and then 6.88 g of 80% mass fraction of hydrazine hydrate solution (0.1 mol) was added. The temperature was raised to 80 ° C. and the reaction was carried out for 2 h. The reaction was then cooled to room temperature and filtered. The solid was washed with anhydrous ethanol until neutral, and then the solid was placed in a vacuum oven and vacuum dried at 35 ° C. for 24 h to obtain a second intermediate product as a white powder;

[0075] To a 250 mL three-necked flask equipped with a mechanical stirring device and a condenser, 4 g of the first intermediate product (0.018 mol), 3 g of the second intermediate product (0.018 mol) and 40 mL of anhydrous ethanol were added. After nitrogen was introduced into the three-necked flask to expel oxygen, 0.28 g of acetic acid was added dropwise. The mixture was reacted under a nitrogen atmosphere at 50 ° C for 1 h, then cooled to room temperature, filtered and washed with anhydrous ethanol, and then placed in a vacuum oven and vacuum dried at 25 ° C for 24 h to obtain a white powder product.

[0076] Example 3

[0077] This embodiment provides a method for preparing a photocurable mussel biomimetic acylhydrazone, comprising the following steps:

[0078] To a 250 mL three-necked flask equipped with a mechanical stirring device and a condenser, 30 g of vanillin (0.20 mol), 34 g of methacrylic anhydride (0.22 mol) and 0.2 g of 4-dimethylaminopyridine were added. After nitrogen was introduced into the three-necked flask to expel oxygen, the mixture was stirred for 24 h under a nitrogen atmosphere and a temperature of 60 ° C., then cooled to room temperature, 150 mL of dichloromethane was added and the mixture was transferred to a separatory funnel. The mixture was first washed with 150 mL of saturated NaHCO3 solution until no bubbles were generated in the mixture, and then washed 3 times with 150 mL of 0.5 mol / L NaOH solution and 150 mL of 1 mol / L NaOH solution, respectively, and finally washed 3 times with deionized water. The organic phase was collected and dried over anhydrous magnesium sulfate overnight. The organic phase was concentrated with a rotary evaporator and the concentrated organic phase was transferred to a glass Petri dish. The glass Petri dish was placed in a vacuum oven at 25 ° C. and vacuum dried for 24 h to obtain a first intermediate product as a white solid.

[0079] To a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser, 8 g of methyl 3,4-dihydroxybenzoate (0.048 mol) and 30 mL of anhydrous ethanol were added, and the mixture was stirred for 15 minutes until the methyl 3,4-dihydroxybenzoate was dissolved in the anhydrous ethanol. Nitrogen was introduced into the three-necked flask to expel oxygen, and then 6 g of a hydrazine hydrate solution (0.096 mol) with a mass fraction of 80% was added. The temperature was raised to 30 ° C. and the reaction was carried out for 24 hours. The mixture was then cooled to room temperature and filtered, and the solid was washed with anhydrous ethanol until neutral. The solid was then placed in a vacuum oven and vacuum dried at 25 ° C. for 24 hours to obtain a second intermediate product in the form of a white powder;

[0080] To a 250 mL three-necked flask equipped with a mechanical stirring device and a condenser, 4 g of the first intermediate product (0.018 mol), 3 g of the second intermediate product (0.018 mol) and 40 mL of anhydrous ethanol were added. After nitrogen was introduced into the three-necked flask to expel oxygen, 0.1750 g of acetic acid was added dropwise. The mixture was reacted under a nitrogen atmosphere at 50 ° C for 1 h, then cooled to room temperature, filtered and washed with anhydrous ethanol, and then placed in a vacuum oven and vacuum dried at 25 ° C for 24 h to obtain a white powder product.

[0081] Vanillin (VA), methyl 3,4-dihydroxybenzoate (MD), the first intermediate product vanillin methyl methacrylate (VA-MA), the second intermediate product protocatechuic acid benzoylhydrazide (MD-HH) and the product photocured mussel biomimetic acylhydrazone (MH-VM) in Examples 1-3 were measured respectively to illustrate the successful synthesis of vanillin methyl methacrylate, methacrylic anhydride and photocured mussel biomimetic acylhydrazone.

[0082] The following is a detailed description using Example 3 as an example, and the VA, MD, VA-MA, MD-HH and MH-VM of Example 3 are measured respectively to illustrate the successful synthesis of the product, the photocured mussel biomimetic acylhydrazone.

[0083] VA and VA-MA were tested by infrared spectroscopy, and the results were as follows: Figure 2 As shown. Figure 2 It can be seen that 3360cm -1 The absorption peaks around 2849 cm are attributed to the stretching vibration peak of the phenolic hydroxyl group of vanillin, but the absorption peaks disappear in VA-MA, indicating that vanillin has completely reacted with methacrylic anhydride. -1 The absorption peak at 1741 cm is attributed to the CH stretching vibration of the aldehyde group. -1 、1703cm -1 and 1637cm -1 The absorption peaks are attributed to -OC=O, HC=O and C=C, respectively, which also confirms that methacrylic anhydride and vanillin have successfully undergone Steglich esterification reaction, indicating the successful synthesis of vanillin methyl methacrylate.

[0084] VA was analyzed by 1H NMR with (CD3)2CO as solvent, and VA-MA was analyzed by 1H NMR with CDCl3 as solvent. The results are as follows Figure 3 As shown. Figure 3 As can be seen, the peak at 9.9 ppm is attributed to the proton peak of the aldehyde group of vanillin methyl methacrylate, indicating that the aldehyde group was well retained. The proton peak of the benzene ring appears between 7.5 ppm and 7.2 ppm, and the proton peaks of the double bond are located at 6.3 ppm and 5.7 ppm, respectively. Due to the different environments of the methyl group, the peaks appear at 3.8 ppm and 2.0 ppm, respectively. The peak at 2.0 ppm is attributed to the proton peak of the methyl group of methacrylic anhydride. These results indicate the successful synthesis of vanillin methyl methacrylate.

[0085] MD and MD-HH were detected by infrared spectroscopy. Figure 4 As shown. Figure 4 It can be seen that 1688cm -1 The absorption peak at 1660 cm-1 is attributed to the stretching vibration of the carbonyl group (C=O) of 3,4-dihydroxybenzoic acid methyl ester. After reacting with hydrazine hydrate, the absorption peak disappears and the peak at 1660 cm-1 is -1 A new absorption peak appeared, which was attributed to the stretching vibration of C=O of hydrazide. -1 A new absorption peak appeared, which was attributed to the bending vibration of hydrazide NN, 3362 cm -1 and 3193cm -1The absorption peak is attributed to the stretching vibration of NH. The above results indicate the successful synthesis of protocatechu benzoyl hydrazide.

[0086] 1H NMR analysis of MD was performed using (CD3)2CO as solvent, and 1H NMR analysis of MD-HH was performed using (CD3)2SO as solvent. The results are as follows Figure 5 As shown. Figure 5 It can be seen that the peaks between 7.5ppm and 6.9ppm are attributed to the proton peaks on the benzene ring, the peak at 3.8ppm is attributed to the proton peak of -CH3 connected to the ester oxygen group of MD, and in the H NMR spectrum of MD, the peaks at 8.3ppm and 8.6ppm are attributed to the two phenolic hydroxyl groups. In the H NMR spectrum of protocatechuic acid benzohydrazide, the peaks at 9.2-9.4ppm are attributed to the two phenolic hydroxyl groups. Compared to MD, the proton peak of -CH3 connected to the ester oxygen group at 3.8ppm in MD-HH disappears, and the proton peak of -NH2 attributable to hydrazide appears at 4.3ppm. These results indicate the successful synthesis of protocatechuic acid benzohydrazide.

[0087] The infrared spectrum of MH-VM was tested and compared with the infrared spectrum of VA-MA and MD-HH. Figure 6 As shown. Figure 6 It can be seen that compared with the infrared spectrum detection results of VA-MA and MD-HH, the infrared spectrum of MH-VM at 1703 cm -1 The C=O absorption peak of the aldehyde group disappears. At the same time, the absorption peak at 1639 cm -1 A new characteristic absorption peak appears at , which is attributed to the stretching vibration of C=N of acylhydrazone, overlapping with the stretching vibration of C=C, indicating that the aldehyde group of VA-MA and the hydrazide of MD-HH react to form an acylhydrazone group (O=C-NH-N=C). The above results indicate the successful synthesis of photocurable mussel biomimetic acylhydrazone.

[0088] MH-VM was analyzed by 1H NMR using (CD3)2SO as solvent. Figure 7 Compared with the H NMR spectra of VA-MA and MD-HH, the peak at 9.9 ppm in the H NMR spectrum of MH-VM, attributed to the proton peak on the aldehyde group, and the proton peak -NH2 at 4.3 ppm attributed to the hydrazide, disappeared. This indicates that the reaction between VA-MA and MD-HH consumed the aldehyde group of VA-MA and the hydrazide of MD-HH. In addition, a new proton peak -CH=N attributed to the acylhydrazone group appeared at 8.4 ppm. Furthermore, the product was relatively pure, with no unreacted VA-MA and MD-HH residues. These results demonstrate the successful synthesis of the photocurable mussel biomimetic acylhydrazone.

[0089] Infrared spectroscopy and 1H NMR analysis were performed on VA, MD, VA-MA, MD-HH and MH-VM in Examples 1-2, respectively. The characteristic peaks of the infrared spectroscopy results and the proton peaks of the 1H NMR results were consistent with those in Example 3, indicating that VA-MA, MD-HH and MH-VM in Experimental Examples 1-2 were also successfully synthesized.

[0090] Example 4

[0091] This embodiment provides a mussel biomimetic light-curing adhesive composition.

[0092] 0.5 g of the photocurable mussel biomimetic acylhydrazone prepared in Example 1 was dissolved in 0.75 g of dimethyl sulfoxide, and 3.5 g of polyethylene glycol dimethacrylate (number average molecular weight of 800) and 0.25 g of PI-1173 were added and mixed uniformly to obtain a mussel biomimetic photocurable adhesive composition, which was recorded as F1.

[0093] Example 5

[0094] This embodiment provides a mussel biomimetic light-curing adhesive composition.

[0095] 1 g of the light-cured mussel biomimetic acylhydrazone prepared in Example 2 was dissolved in 0.75 g of dimethyl sulfoxide, and 3 g of polyethylene glycol dimethacrylate (number average molecular weight of 800) and 0.25 g of PI-1173 were added and mixed uniformly to obtain a mussel biomimetic light-cured adhesive composition, which was recorded as F2.

[0096] Example 6

[0097] 1.5 g of the light-cured mussel biomimetic acylhydrazone prepared in Example 3 was dissolved in 0.75 g of dimethyl sulfoxide, and 2.5 g of polyethylene glycol dimethacrylate (number average molecular weight of 800) and 0.25 g of PI-1173 were added and mixed uniformly to obtain a mussel biomimetic light-cured adhesive composition, which was recorded as F3.

[0098] Comparative Example 1

[0099] This comparative example provides a photocurable adhesive composition.

[0100] 4 g of polyethylene glycol dimethacrylate (number average molecular weight of 800), 0.75 g of dimethyl sulfoxide and 0.25 g of PI-1173 were mixed uniformly to obtain a light-curing adhesive composition, which was recorded as F0.

[0101] Experimental Example 1

[0102] In this experimental example, the mussel biomimetic light-curing adhesive compositions of Examples 4-6 and the light-curing adhesive composition of Comparative Example 1 were subjected to differential scanning calorimetry analysis. The test results are shown in FIG. Figure 8 As shown. Figure 8 It can be seen that with the increase of the content of photocurable mussel biomimetic acylhydrazone in the photocurable adhesive composition, the heat flow of the mussel biomimetic photocurable adhesive composition within a certain temperature range changes little, and the glass transition temperature increases, indicating that photocurable mussel biomimetic acylhydrazone is beneficial to the enhancement of thermal stability.

[0103] Experimental Example 2

[0104] In this experimental example, the overlapping method was used to test the bonding performance of the mussel biomimetic light-curing adhesive compositions of Examples 4-6 and the light-curing adhesive composition (F0-F3) of Comparative Example 1.

[0105] The lap shear test was evaluated using a SUNS Technology UTM 6104 universal tensile testing machine. The substrates included acrylic (PMMA), aluminum sheets (AL) and wood boards (Plank). Before use, the substrates were cleaned and ultrasonicated in ethanol for 30 minutes, and then air-dried overnight. 0.30 g of F0-F3 were applied to the acrylic respectively, and then the substrates were placed on the acrylic to form a square lap area of ​​2 cm × 2 cm. Finally, the samples were cured by UV curing machine. After F0-F3 was cured by UV light with a wavelength of 365 nm for 120 seconds, the lap shear test was immediately carried out. The sample preparation method is as follows. Figure 9 As shown. . Then, the specimens bonded with F0-F3 were placed on a vertical fixture, and the crosshead of the universal tensile machine maintained a uniform strain rate of 5mm / min to test the stress that causes the adhesive joint to fail under the action of a tensile load parallel to the axial direction of the adhesive surface layer. 3 to 5 tests were performed on each specimen to obtain the average value and standard mean error. The results are shown in Figure 10 shown.

[0106] from Figure 10 It can be seen that the bonding strength of F1-F3 on acrylic, aluminum, and wood substrates is improved compared to F0. Furthermore, the bonding strength increases with increasing amounts of the photocurable mussel biomimetic acylhydrazone, indicating that the photocurable mussel biomimetic acylhydrazone can enhance the adhesion of the mussel biomimetic photocurable adhesive composition to different substrates. The mussel biomimetic photocurable adhesive significantly improves the bonding performance on aluminum. It can be observed that F0, without the photocurable mussel biomimetic acylhydrazone, barely forms effective adhesion to the aluminum sheet. The maximum bonding strength of the mussel biomimetic photocurable adhesive to the aluminum sheet reached 0.5973 MPa.

[0107] Experimental Example 3

[0108] In this experimental example, the mussel biomimetic light-curing adhesive compositions of Examples 4-6 and the light-curing adhesive composition (F0-F3) of Comparative Example 1 were subjected to thermogravimetric analysis tests.

[0109] 3 to 5 g of F0-F3 were placed in a culture dish with a diameter of 100 mm, left to stand for half an hour, and then exposed to 365 nm ultraviolet light for 120 seconds to obtain the cured films of F0-F3 of this experimental example.

[0110] The test results are as follows Figure 11 As shown, Figure 11 (a) is the TGA curve of the cured film of F0-F3, Figure 11 (b) is the DTG curve of the cured film of F0-F3. Figure 11 It can be seen that the maximum thermal degradation temperature of the cured films of F1-F3 is about 400℃, which is slightly higher than that of the cured film of F0. 10％ ), 50% thermal degradation temperature (T 50％ ) and the maximum degradation rate temperature (T max ) and the residual carbon rate at 700℃ are listed in Table 1. As can be seen from Table 1, with the increase of the content of light-cured mussel biomimetic acylhydrazone, T max The value increases first and then decreases, T max The highest temperature can reach 402℃, T 50％ The highest temperature can reach 393.1℃. Compared with the cured film of F0, the carbon residue of the cured film first decreases and then increases with the increase of the light-cured mussel biomimetic acylhydrazone content. The above results indicate that the mussel biomimetic light-cured adhesive composition has good thermal stability.

[0111] Table 1 Thermal decomposition data of F0-F3 cured films

[0112] sample <![CDATA[T 10％ (℃)]]> <![CDATA[T 50％ (℃)]]> <![CDATA[T max (1 st / 2 nd / 3 rd )(℃)]]> Residual carbon rate (%) F0 322.9 383.4 40.2 / 390.3 8.21 F1 309.5 389.5 41.3 / 91.4 / 400.9 0.52 F2 249.6 393.1 41.2 / 101.4 / 402.0 11.92 F3 118.4 387.4 43.9 / 108.6 / 397.9 13.36

[0113] Experimental Example 4

[0114] In this experimental example, the infrared absorption peak area of ​​the main functional groups of the mussel biomimetic light-curing adhesive composition of Examples 4-6 and the light-curing adhesive composition (F0-F3) of Comparative Example 1 before and after light curing was tested. 3-5g of F0-F3 were placed in a culture dish with a diameter of 100mm, left to stand for half an hour, and then exposed to 365nm ultraviolet light for 120 seconds to obtain the cured films of F0-F3 for subsequent testing. The test results are shown in Figure 2. Figure 12 As shown, Figure 12 (a) is the infrared absorption peak of the main functional groups of F0-F3 before photocuring, Figure 12 (b) is the infrared absorption peak of the main functional groups of F0-F3 after photocuring. Figure 12It can be seen that after the addition of the photocurable mussel biomimetic acylhydrazone, the conversion rate of C=C decreased significantly, which may be due to the inhibition effect of the phenolic hydroxyl group. However, the lowest conversion rate of C=C after photocuring can also be greater than 60%, indicating that the carbon-carbon double bond conversion rate of the mussel biomimetic photocurable adhesive composition after UV curing is still at a good level.

[0115] Experimental Example 5

[0116] In this experimental example, the general performance of the cured films of the mussel biomimetic photocurable adhesive compositions of Examples 4-6 and the photocurable adhesive composition (F0-F3) of Comparative Example 1 was analyzed, and the acid resistance, alkali resistance, gel fraction and pencil hardness were tested respectively. The test results are listed in Table 2.

[0117] The preparation method of the F0-F3 cured film of this experimental example is as follows: 3-5g of F0-F3 are placed in a culture dish with a diameter of 100mm, left to stand for half an hour, and then exposed to 365nm ultraviolet light for 120 seconds to obtain the obtained film.

[0118] The acid resistance test method is to weigh 0.2000 to 0.5000 g of the cured films of samples F0-F3 respectively at room temperature, immerse them in a sealed glass bottle filled with 10% hydrochloric acid solution for 24 hours, and record the morphology of the samples before and after immersion.

[0119] The alkali resistance test method is to weigh 0.2000 to 0.5000 g of the cured films of samples F0-F3 respectively at room temperature, immerse them in a sealed glass bottle containing 10% sodium hydroxide solution for 24 hours, and record the morphology of the samples before and after immersion.

[0120] The gel content test method is to weigh 0.2000-0.5000g of the cured film of samples F0-F3 at room temperature and immerse them in a sealed glass bottle filled with acetone. After immersion for 48 hours, the cured film samples are removed and placed in a vacuum drying oven at 60°C to dry to constant weight. The mass of the cured film before immersion, W0, and the mass of the cured film after drying, W1, are recorded. The gel content is calculated by three measurements for each sample and the average value is taken. The calculation formula is:

[0121]

[0122] The pencil hardness test method is to test the pencil hardness of the cured films of samples F0-F3 according to GB / T 6739-1996.

[0123] Table 2 General performance analysis of cured films F0-F3

[0124] sample Acid resistance Alkali resistance Gel content (%) Pencil hardness F0 No significant changes No significant changes 89.22±0.71 5B F1 No significant changes Surface turns brown 73.88±0.22 1H F2 No significant changes Surface turns brown 70.96±0.60 1H F3 No significant changes Surface turns brown 66.99±0.68 2H

[0125] As shown in Table 2, compared to the photocurable adhesive composition, the cured film of the mussel biomimetic photocurable adhesive composition containing the photocurable mussel biomimetic acylhydrazone exhibited good acid resistance, but decreased alkali resistance and gel fraction, while improving pencil hardness test results. With increasing content of the photocurable mussel biomimetic acylhydrazone, the gel fraction of the cured film decreased, likely due to the inhibition of the phenolic hydroxyl group affecting the crosslinking degree of the cured film. The good pencil hardness test results indicate that the photocurable mussel biomimetic acylhydrazone can increase the wear resistance of the cured film of the photocurable adhesive composition.

[0126] Therefore, compared with the prior art, the present invention has the following beneficial effects:

[0127] (1) The photocurable mussel biomimetic acylhydrazone of the present invention has low raw material cost; its molecular structure has both a catechol structure that simulates mussel adhesion and a carbon-carbon double bond that can participate in photocuring, and can be used as a new mussel biomimetic material;

[0128] (2) The preparation method of the light-cured mussel biomimetic acylhydrazone of the present invention comprises the following steps: first, methacrylic anhydride and vanillin undergo a Steglich esterification reaction to synthesize vanillin methyl methacrylate; then, 3,4-dihydroxybenzoic acid methyl ester and hydrazine hydrate undergo an ester hydrazinolysis reaction to synthesize protocatechuic acid benzoylhydrazine; and finally, vanillin methyl methacrylate and protocatechuic acid benzoylhydrazine undergo a Schiff base reaction to synthesize the light-cured mussel biomimetic acylhydrazone. The synthesis process does not require protection and deprotection of the catechol structure, the preparation method is simple, and the synthesis difficulty and production cost of the mussel biomimetic material are reduced;

[0129] (3) The mussel biomimetic photocurable adhesive composition prepared by the present invention using photocurable mussel biomimetic acylhydrazone as raw material, the carbon-carbon double bond of the photocurable mussel biomimetic acylhydrazone undergoes a cross-linking reaction with the resin matrix, and the catechol structure is used to give the composition good adhesive properties. At the same time, within the preferred addition amount range, the carbon-carbon double bond conversion rate after photocuring is high, and the curing effect and mechanical properties of the adhesive are good. The problem of insufficient adhesion and failure of the photocurable adhesive causing shedding can be improved. In addition, the cured film of the mussel biomimetic photocurable adhesive composition of the present invention has good acid resistance and coating hardness.

[0130] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A photocurable mussel biomimetic acylhydrazone, characterized in that: The structural formula of the photocurable mussel biomimetic acylhydrazone is shown in formula (I): Formula (I).

2. The method for preparing the light-cured mussel biomimetic acylhydrazone according to claim 1, characterized in that: The following steps are involved: Dissolve vanillin methyl methacrylate and protocatechuic acid benzoyl hydrazide in an organic solvent, add acetic acid in a nitrogen atmosphere, react at 50-80°C for 1-4 hours, then purify and dry to obtain the product; The molar ratio of the vanillin methyl methacrylate to the protocatechuic acid benzoyl hydrazide is 1:(0.9-1.3), and the organic solvent is selected from at least one of methanol and anhydrous ethanol.

3. The preparation method according to claim 2, characterized in that The amount of acetic acid used is 2-5% of the total mass of vanillin methyl methacrylate, protocatechu benzoyl hydrazide and acetic acid.

4. The preparation method according to claim 2, characterized in that The preparation method of vanillin methyl methacrylate comprises the following steps: Mix vanillin, methacrylic anhydride and 4-dimethylaminopyridine, react at 50-80°C in a nitrogen atmosphere for 24-48 hours, then purify and dry to obtain; Wherein, the molar ratio of the vanillin to the methacrylic anhydride is 1:(1.1-2.0).

5. The preparation method according to claim 4, characterized in that The amount of 4-dimethylaminopyridine used is 0.2-1% of the total mass of vanillin, methacrylic anhydride and 4-dimethylaminopyridine.

6. The preparation method according to claim 2, characterized in that The preparation method of protocatechu benzoyl hydrazide comprises the following steps: Dissolve methyl 3,4-dihydroxybenzoate in an organic solvent, add hydrazine hydrate solution in a nitrogen atmosphere, react at 25-80°C for 2-24 hours, then purify and dry to obtain the product; Wherein, the molar ratio of the methyl 3,4-dihydroxybenzoate to the hydrazine hydrate is 1:(1.0~2).

7. The preparation method according to claim 6, characterized in that The mass fraction of hydrazine hydrate in the hydrazine hydrate solution is 70-90%, and the organic solvent is selected from at least one of methanol and anhydrous ethanol.

8. Use of the light-curable mussel biomimetic acylhydrazone according to claim 1 in a mussel biomimetic light-curable adhesive composition.

9. A mussel biomimetic light-curing adhesive composition, characterized in that: It is prepared by a reaction system consisting of a resin matrix, a solvent, a photoinitiator and the photocurable mussel biomimetic acylhydrazone according to claim 1; The mass of the resin matrix is ​​50% to 80% of the total mass of the reaction system, the mass of the solvent is 10% to 20% of the total mass of the reaction system, the mass of the photoinitiator is 4% to 6% of the total mass of the reaction system, and the mass of the photocurable mussel biomimetic acylhydrazone is 1% to 30% of the total mass of the reaction system. The resin matrix is ​​polyethylene glycol dimethacrylate; the solvent is selected from at least one of dimethyl sulfoxide, tetrahydrofuran, and N,N-dimethylformamide; and the photoinitiator is selected from at least one of PI-1173, PI-2959, and TPO.

10. The method for preparing the mussel biomimetic light-curing adhesive composition according to claim 9, characterized in that: The photocurable mussel biomimetic acylhydrazone is dissolved in a solvent, and then a resin matrix and a photoinitiator are added and mixed evenly to obtain the product.

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