A method for preparing a high-strength, recyclable, repairable, fast-curing bio-based adhesive.

Abstract

This invention discloses a method for preparing a high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesive, comprising the following steps: First, cellulose, 2-(tert-butylamino)ethyl methacrylate, diisocyanate, and a catalyst are dissolved in a good solvent at a certain molar ratio and reacted at 40–100°C for 2–8 hours to prepare a cellulose-based macromonomer containing dynamically hindered urea bonds; Second, the cellulose-based macromonomer, methacrylate, and photoinitiator are dissolved in a good solvent at a certain mass ratio, poured into a mold, and after the solvent evaporates, cured under ultraviolet light for 1–10 minutes to prepare a high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesive. This invention provides a simple and efficient way to prepare a green and environmentally friendly high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesive.

Description

Technical Field

[0001] This invention relates to a method for preparing a high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesive. Background Technology

[0002] Adhesives are polymeric materials that can bond two or more materials together through interfacial adhesion and cohesion. They are widely used in packaging, construction, electronics, and medical and health fields, and are an indispensable bonding material in daily life. Currently, there are many types of adhesives developed, which can be divided into natural adhesives and synthetic adhesives according to their source. Compared with natural adhesives, synthetic adhesives have advantages such as well-defined structures and controllable functions, effectively improving the bonding strength of adhesives and endowing them with specific functions such as corrosion resistance and anti-aging. However, the raw materials for the production of traditional synthetic adhesives are mostly derived from petrochemical products, making them difficult to degrade or recycle, resulting in a large amount of waste pollution. At the same time, most traditional adhesives require prolonged heating during the curing process, resulting in significant energy consumption. Therefore, the preparation of high-strength, rapidly curable bio-based adhesives with recyclability can effectively reduce energy consumption, extend the service life of adhesives, and solve environmental pollution problems.

[0003] Cellulose, as the world's most abundant biomass resource, boasts advantages such as environmental friendliness, low cost, and numerous reactive hydroxyl groups. It has been widely used in synthetic plastics, coatings, rubber substitutes, inks, and insulating materials, showing promise as a partial substitute for petroleum fossil resources. The polyhydroxy structure of cellulose allows for the easy introduction of various active groups or dynamic covalent bonds through chemical modification, making it suitable for constructing recyclable, repairable, and rapidly curing bio-based adhesives. Simultaneously, cellulose's rigid molecular framework effectively enhances the strength of bio-based adhesives, enabling the preparation of high-strength bio-based adhesives that are green and sustainable.

[0004] Therefore, by preparing high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesives, the problems of non-renewable, serious environmental pollution, and high energy consumption in traditional synthetic adhesives can be solved. This is of great significance for the further development of green and environmentally friendly high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesives. Summary of the Invention

[0005] Objectives of the Invention: One objective of this invention is to provide a high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesive. This bio-based adhesive not only possesses excellent bonding strength and rapid photocuring capability but also exhibits excellent reprocessability, thereby enhancing the practical value of bio-based adhesives. A second objective of this invention is to provide a method for preparing a high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesive, characterized by simple operation, mild reaction conditions, and good repeatability.

[0006] Technical solution: The present invention provides a high-strength, recyclable, repairable, fast-curing bio-based adhesive, the general structural formula of which is shown below:

[0007] ,

[0008] Wherein, R is a characteristic functional group of cellulose, which is H or any one of -CH3, -CH2CH3, -CH2COOH, -COCH3, -CH2CH2OH, -CH2CH2CH2OH, R1 is a structural unit of diisocyanate, and R2 is a structural unit of methacrylate.

[0009] This invention also provides a method for preparing a high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesive, comprising the following steps:

[0010] (1) Cellulose, 2-(tert-butylamino)ethyl methacrylate, diisocyanate and catalyst are reacted in a good solvent at a certain molar ratio at 40~100 °C for 2~8 h to prepare cellulose-based macromonomers with dynamic sterically hindered urea bonds;

[0011] (2) Dissolve cellulose-based macromolecular monomers, methacrylates, and photoinitiators in a certain mass ratio in a good solvent and pour them into a mold. After the solvent evaporates, cure under ultraviolet light for 1 to 10 minutes to prepare a high-strength, recyclable, repairable, fast-curing bio-based adhesive.

[0012] In step (1) above, the molar ratio of cellulose, 2-(tert-butylamino)ethyl methacrylate, diisocyanate, and catalyst is [cellulose] : [2-(tert-butylamino)ethyl methacrylate] : [diisocyanate] : [catalyst] = 1:1~7:1~4:0.05~0.2.

[0013] The cellulose is any one of methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, cellulose acetate, microcrystalline cellulose, and nanocellulose; the diisocyanate is any one of diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and lysine diisocyanate; the catalyst is any one of stannous octoate and dibutyltin dilaurate; and the good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, N,N-dimethylacetamide / lithium chloride, toluene, and tetrahydrofuran.

[0014] In step (2) above, the mass ratio of cellulose-based macromonomer, methacrylate, and photoinitiator is [cellulose-based macromonomer] : [methacrylate] : [photoinitiator] = 1 : 0.5~3 : 0.02~0.1.

[0015] The methacrylate is any one of methyl methacrylate, lauryl methacrylate, tetrahydrofurfuryl methacrylate, furfuryl methacrylate, and hydroxyethyl methacrylate; the photoinitiator is any one of 2-hydroxy-2-methylphenylacetone and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide; and the good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, N,N-dimethylacetamide / lithium chloride, toluene, and tetrahydrofuran.

[0016] Beneficial effects:

[0017] (1) The preparation method of the high-strength, recyclable, repairable, and fast photocurable bio-based adhesive involved in this invention has the characteristics of simple operation and good repeatability, and can prepare bio-based adhesives with high strength, recyclability, repairability, and fast photocurability.

[0018] (2) The high-strength, recyclable, repairable, fast-curing bio-based adhesive involved in this invention can be used as a new type of bio-based adhesive. In addition to having excellent mechanical properties and fast-curing ability, it also has excellent recyclability and repairability, making it suitable for a wider range of applications. Attached Figure Description

[0019] Figure 1 The infrared spectra of ethyl cellulose and ethyl cellulose macromonomer in Example 1 are shown.

[0020] Figure 2 The figures show the uniaxial tensile stress-strain curves before and after the recycling of the ethyl cellulose-based adhesive in Example 1.

[0021] Figure 3 The image shows the bonding strength curve of the ethyl cellulose-based adhesive used in Example 1 for bonding to a glass substrate. Detailed Implementation

[0022] The invention will be further described in detail below with reference to examples.

[0023] The raw materials and reagents used in the following examples are all commercially available.

[0024] Example 1: Preparation of a high-strength, recyclable, repairable, fast-curing bio-based adhesive using ethyl cellulose

[0025] Step 1: Ethyl cellulose, 2-(tert-butylamino)ethyl methacrylate, diphenylmethane diisocyanate, and stannous octoate were dissolved in toluene in a molar ratio of [ethyl cellulose] : [2-(tert-butylamino)ethyl methacrylate] : [diphenylmethane diisocyanate] : [stannous octoate] = 1 : 3 : 2 : 0.1 and reacted at 50 °C for 8 h to prepare a macromonomer of ethyl cellulose containing dynamic sterically hindered urea bonds;

[0026] Step 2: Dissolve ethyl cellulose macromonomer, tetrahydrofurfuryl methacrylate, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide in toluene at a mass ratio of [ethyl cellulose macromonomer] : [tetrahydrofurfuryl methacrylate] : [diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide] = 1 : 0.5 : 0.05. Pour the solution into a mold and cure under UV light for 10 min after the toluene has evaporated to prepare a high-strength, recyclable, repairable, and fast-curing ethyl cellulose-based adhesive.

[0027] Figure 1 The image shows the infrared spectra of ethyl cellulose and its macromonomer in Example 1, with the value at 3319 cm⁻¹. -1 and 1637 cm -1 The presence of absorption peaks corresponding to the amide and vinyl groups of the ethyl cellulose macromonomer indicates the successful preparation of a dynamically hindered urea bond-containing ethyl cellulose macromonomer that can be rapidly photocured.

[0028] Figure 2 The figure shows the uniaxial tensile stress-strain curves of the ethyl cellulose-based adhesive before and after recycling in Example 1. As can be seen from the figure, the adhesive has excellent mechanical properties before and after recycling, and the mechanical strength recovery efficiency reaches 89.4%, indicating that the adhesive has high strength and good recyclability and repairability.

[0029] Figure 3 The figure shows the bonding strength curve of the ethyl cellulose-based adhesive used in Example 1 for bonding glass substrates. As can be seen from the figure, the bonding strength of the glass substrate bonded by the adhesive can reach 64 MPa, indicating that the adhesive has excellent bonding ability.

[0030] Example 2: Preparation of a high-strength, recyclable, repairable, fast-curing bio-based adhesive using methylcellulose

[0031] Step 1: Methylcellulose, 2-(tert-butylamino)ethyl methacrylate, diphenylmethane diisocyanate, and stannous octoate were dissolved in tetrahydrofuran in a molar ratio of [methylcellulose] : [2-(tert-butylamino)ethyl methacrylate] : [diphenylmethane diisocyanate] : [stannous octoate] = 1 : 1 : 1 : 0.05 and reacted at 40 °C for 8 h to prepare a methylcellulose macromonomer containing dynamically hindered urea bonds;

[0032] Step 2: Dissolve methylcellulose macromonomer, tetrahydrofurfuryl methacrylate, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide in tetrahydrofuran at a mass ratio of [methylcellulose macromonomer] : [tetrahydrofurfuryl methacrylate] : [diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide] = 1:1:0.1. Pour the solution into a mold and cure under UV light for 5 minutes after the tetrahydrofuran has evaporated to prepare a high-strength, recyclable, repairable, and fast-curing methylcellulose-based adhesive.

[0033] Example 3: Preparation of a high-strength, recyclable, repairable, fast-curing bio-based adhesive using carboxymethyl cellulose

[0034] Step 1: Dissolve carboxymethyl cellulose, 2-(tert-butylamino)ethyl methacrylate, isophorone diisocyanate, and dibutyltin dilaurate in dichloromethane at a molar ratio of [carboxymethyl cellulose] : [2-(tert-butylamino)ethyl methacrylate] : [isophorone diisocyanate] : [dibutyltin dilaurate] = 1 : 5 : 3 : 0.15 and react at 80 °C for 3 h to prepare a carboxymethyl cellulose macromonomer containing dynamic sterically hindered urea bonds;

[0035] Step 2: Dissolve carboxymethyl cellulose macromonomer, methyl methacrylate, and 2-hydroxy-2-methylphenylacetone in dichloromethane at a mass ratio of [carboxymethyl cellulose macromonomer] : [methyl methacrylate] : [2-hydroxy-2-methylphenylacetone] = 1:3:0.1, pour the solution into a mold, and cure under ultraviolet light for 2 minutes after the dichloromethane has evaporated to prepare a high-strength, recyclable, repairable, and fast-curing carboxymethyl cellulose-based adhesive.

[0036] Example 4: Preparation of high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesives using microcrystalline cellulose

[0037] Step 1: Microcrystalline cellulose, 2-(tert-butylamino)ethyl methacrylate, hexamethylene diisocyanate, and dibutyltin dilaurate were dissolved in an N,N-dimethylacetamide / lithium chloride system at a molar ratio of [microcrystalline cellulose] : [2-(tert-butylamino)ethyl methacrylate] : [hexamethylene diisocyanate] : [dibutyltin dilaurate] = 1 : 2 : 2 : 0.1 and reacted at 40 °C for 6 h to prepare a microcrystalline cellulose macromonomer containing dynamic sterically hindered urea bonds.

[0038] Step 2: Dissolve microcrystalline cellulose macromonomer, glycidyl methacrylate, and 2-hydroxy-2-methylphenylacetone in dichloromethane at a mass ratio of [microcrystalline cellulose macromonomer] : [glycidyl methacrylate] : [2-hydroxy-2-methylphenylacetone] = 1:2:0.05, pour the solution into a mold, and cure under ultraviolet light for 3 minutes after the dichloromethane has evaporated to prepare a high-strength, recyclable, repairable, and fast-curing microcrystalline cellulose-based adhesive.

[0039] Example 5: Preparation of high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesives using nanocellulose

[0040] Step 1: Dissolve nanocellulose, 2-(tert-butylamino)ethyl methacrylate, lysine diisocyanate, and stannous octoate in N,N-dimethylformamide at a molar ratio of [nanocellulose] : [2-(tert-butylamino)ethyl methacrylate] : [lysine diisocyanate] : [stannous octoate] = 1 : 7 : 4 : 0.2 and react at 100 °C for 2 h to prepare nanocellulose macromonomers containing dynamic sterically hindered urea bonds.

[0041] Step 2: Dissolve nanocellulose macromonomers, lauryl methacrylate, and 2-hydroxy-2-methylphenylacetone in tetrahydrofuran at a mass ratio of [nanocellulose macromonomers] : [lauryl methacrylate] : [2-hydroxy-2-methylphenylacetone] = 1:2:0.1, pour the solution into a mold, and cure under UV light for 5 minutes after the tetrahydrofuran has evaporated to prepare a high-strength, recyclable, repairable, and fast-curing nanocellulose-based adhesive.

[0042] Example 6: Preparation of a high-strength, recyclable, repairable, fast-curing bio-based adhesive using hydroxyethyl cellulose

[0043] Step 1: Hydroxyethyl cellulose, 2-(tert-butylamino)ethyl methacrylate, diphenylmethane diisocyanate, and stannous octoate were dissolved in N,N-dimethylformamide in a molar ratio of [hydroxyethyl cellulose] : [2-(tert-butylamino)ethyl methacrylate] : [diphenylmethane diisocyanate] : [stannous octoate] = 1 : 2 : 1 : 0.1 and reacted at 50 °C for 4 h to prepare a macromonomer of hydroxyethyl cellulose containing dynamic sterically hindered urea bonds;

[0044] Step 2: Dissolve hydroxyethyl cellulose macromonomer, furfuryl methacrylate, and 2-hydroxy-2-methylphenylacetone in dimethyl sulfoxide at a mass ratio of [hydroxyethyl cellulose macromonomer] : [furfuryl methacrylate] : [2-hydroxy-2-methylphenylacetone] = 1:3:0.2, pour the solution into a mold, and cure under UV light for 10 min after the dimethyl sulfoxide has evaporated to prepare a high-strength, recyclable, repairable, and fast-curing hydroxyethyl cellulose-based adhesive.

[0045] Example 7: Preparation of a high-strength, recyclable, repairable, fast-curing bio-based adhesive using cellulose acetate.

[0046] Step 1: Dissolve cellulose acetate, 2-(tert-butylamino)ethyl methacrylate, hexamethylene diisocyanate, and stannous octoate in N,N-dimethylformamide at a molar ratio of [cellulose acetate] : [2-(tert-butylamino)ethyl methacrylate] : [hexamethylene diisocyanate] : [stannous octoate] = 1 : 3 : 2 : 0.1 and react at 60 °C for 4 h to prepare a macromonomer of cellulose acetate containing dynamic sterically hindered urea bonds.

[0047] Step 2: Dissolve cellulose acetate macromonomer, hydroxyethyl methacrylate, and 2-hydroxy-2-methylphenylacetone in N,N-dimethylformamide at a mass ratio of [cellulose acetate macromonomer] : [hydroxyethyl methacrylate] : [2-hydroxy-2-methylphenylacetone] = 1:1:0.05, then pour the solution into a mold. After the N,N-dimethylformamide has evaporated, cure the adhesive under UV light for 4 minutes to prepare a high-strength, recyclable, repairable, and fast-curing cellulose acetate-based adhesive.

[0048] Example 8: Preparation of a high-strength, recyclable, repairable, fast-curing bio-based adhesive using hydroxypropyl cellulose

[0049] Step 1: Hydroxypropyl cellulose, 2-(tert-butylamino)ethyl methacrylate, dicyclohexylmethane diisocyanate, and dibutyltin dilaurate were dissolved in toluene in a molar ratio of [hydroxypropyl cellulose] : [2-(tert-butylamino)ethyl methacrylate] : [dicyclohexylmethane diisocyanate] : [dibutyltin dilaurate] = 1 : 4 : 2 : 0.15 and reacted at 80 °C for 4 h to prepare a hydroxypropyl cellulose macromonomer containing dynamically hindered urea bonds.

[0050] Step 2: Dissolve hydroxypropyl cellulose macromonomer, furfuryl methacrylate, and 2-hydroxy-2-methylphenylacetone in toluene at a mass ratio of [hydroxypropyl cellulose macromonomer] : [furfuryl methacrylate] : [2-hydroxy-2-methylphenylacetone] = 1 : 1.5 : 0.1, pour the solution into a mold, and cure under ultraviolet light for 10 min after the toluene has evaporated to prepare a high-strength, recyclable, repairable, and fast-curing hydroxypropyl cellulose-based adhesive.

[0051] Tests revealed that the high-strength, recyclable, repairable, and rapidly photocurable bio-based adhesives prepared in Examples 1-8 above have high strength and can be recycled through reprocessing, extending the service life of bio-based adhesives and expanding their application areas.

Claims

1. A high-strength, recyclable, repairable, fast-curing bio-based adhesive, characterized in that... The general structural formula is as follows: Wherein, R is a characteristic functional group of cellulose, which is H or any one of -CH3, -CH2CH3, -CH2COOH, -COCH3, -CH2CH2OH, R1 is a structural unit of diisocyanate, and R2 is a structural unit of methacrylate. The preparation method of the high-strength, recyclable, repairable, fast-curing bio-based adhesive includes the following steps: (1) Cellulose, 2-(tert-butylamino)ethyl methacrylate, diisocyanate, and catalyst are dissolved in a good solvent in a certain molar ratio and reacted at 40-100℃ for 2-8 hours to prepare a cellulose-based macromonomer containing dynamically hindered urea bonds. The molar ratio of cellulose, 2-(tert-butylamino)ethyl methacrylate, diisocyanate, and catalyst is cellulose:2-(tert-butylamino)ethyl methacrylate:diisocyanate:catalyst = 1:1-7:1-4:0.05-0.

2. The cellulose is methylcellulose, ethylcellulose, or carboxymethylcellulose. The diisocyanate is any one of methylcellulose, hydroxyethylcellulose, cellulose acetate, microcrystalline cellulose, and nanocellulose; the diisocyanate is any one of diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and lysine diisocyanate; the catalyst is any one of stannous octoate and dibutyltin dilaurate; and the good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, N,N-dimethylacetamide / lithium chloride, toluene, and tetrahydrofuran. (2) Dissolve cellulose-based macromonomers, methacrylates, and photoinitiators in a certain mass ratio in a good solvent and pour the solution into a mold. After the solvent evaporates, cure the solution under ultraviolet light for 1-10 minutes to prepare a high-strength, recyclable, repairable, fast-curing bio-based adhesive. The cellulose-based macromonomers, methacrylates, and photoinitiators are in a certain mass ratio of cellulose-based macromonomers: methacrylates: photoinitiators = 1:0.5-3:0.02-0.

1. The methacrylates are any one of methyl methacrylate, lauryl methacrylate, tetrahydrofurfuryl methacrylate, furfuryl methacrylate, and hydroxyethyl methacrylate. The photoinitiators are any one of 2-hydroxy-2-methylphenylacetone and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. The good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, N,N-dimethylacetamide / lithium chloride, toluene, and tetrahydrofuran.

2. The method for preparing a high-strength, recyclable, repairable, fast-curing bio-based adhesive according to claim 1, characterized in that... Includes the following steps: (1) Cellulose, 2-(tert-butylamino)ethyl methacrylate, diisocyanate, and catalyst are dissolved in a good solvent in a certain molar ratio and reacted at 40-100℃ for 2-8 hours to prepare a cellulose-based macromonomer containing dynamically hindered urea bonds. The molar ratio of cellulose, 2-(tert-butylamino)ethyl methacrylate, diisocyanate, and catalyst is cellulose:2-(tert-butylamino)ethyl methacrylate:diisocyanate:catalyst = 1:1-7:1-4:0.05-0.

2. The cellulose is methylcellulose, ethylcellulose, or carboxymethylcellulose. The diisocyanate is any one of methylcellulose, hydroxyethylcellulose, cellulose acetate, microcrystalline cellulose, and nanocellulose; the diisocyanate is any one of diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and lysine diisocyanate; the catalyst is any one of stannous octoate and dibutyltin dilaurate; and the good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, N,N-dimethylacetamide / lithium chloride, toluene, and tetrahydrofuran. (2) Dissolve cellulose-based macromonomers, methacrylates, and photoinitiators in a certain mass ratio in a good solvent and pour the solution into a mold. After the solvent evaporates, cure the solution under ultraviolet light for 1-10 minutes to prepare a high-strength, recyclable, repairable, fast-curing bio-based adhesive. The cellulose-based macromonomers, methacrylates, and photoinitiators are in a certain mass ratio of cellulose-based macromonomers: methacrylates: photoinitiators = 1:0.5-3:0.02-0.

1. The methacrylates are any one of methyl methacrylate, lauryl methacrylate, tetrahydrofurfuryl methacrylate, furfuryl methacrylate, and hydroxyethyl methacrylate. The photoinitiators are any one of 2-hydroxy-2-methylphenylacetone and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. The good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, N,N-dimethylacetamide / lithium chloride, toluene, and tetrahydrofuran.

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