Eco-friendly adhesive comprising lignin hydrogel and method for manufacturing eco-friendly lignin hydrogel

Abstract

The objective of the present invention is to provide an eco-friendly and economical eco-friendly adhesive using a lignin hydrogel. To achieve the objective, the lignin hydrogel in the eco-friendly adhesive comprising the lignin hydrogel according to the present invention comprises a network structure formed through bonds between lignin and an amphoteric ionic polymer.

Description

Eco-friendly adhesive containing lignin hydrogel and method for producing eco-friendly lignin hydrogel

[0001] The present invention relates to an eco-friendly adhesive comprising a lignin hydrogel, and in particular, the lignin hydrogel is characterized by comprising a network structure through the combination of a lignin-based material and a zwitterionic polymer.

[0002] Recently, there has been active development of eco-friendly adhesives. Eco-friendly adhesives are designed to minimize negative impacts on the environment and human health, and can be applied in a variety of fields, including cosmetics, food packaging, and biodegradable adhesives.

[0003] Among eco-friendly adhesives, bioadhesives are adhesives that can adhere to biological tissue. They are widely used in medical applications and can be utilized in areas such as wound healing, tissue regeneration, and drug delivery. Bioadhesives are primarily protein-based, polysaccharide-based, and synthetic polymer-based materials, and require properties such as biocompatibility, adhesion, biodegradability, and flexibility.

[0004] Meanwhile, lignin is one of the three main components of plant cell walls and is the second most abundant plant polymer on Earth. Not only is lignin abundant in nature, it is also a valuable byproduct of the pulp and paper industry. While approximately 50 million tons of lignin are produced annually, most of it is either discarded or used as fuel.

[0005] Recently, research is being conducted on methods for producing high value-added functional materials such as bioplastics, adhesives, and dispersants to utilize the environmental and economic values ​​of lignin, such as biocompatibility, eco-friendliness, and low toxicity. However, lignin's irregular structure and its inability to mix well with other substances have resulted in its limited application in actual industries.

[0006] The purpose of the present invention is to provide an eco-friendly and economical adhesive using lignin hydrogel.

[0007] In addition, the purpose is to provide a method for manufacturing lignin hydrogel for an eco-friendly adhesive that can be mass-produced in a simple and economical manner.

[0008] In order to achieve the above purpose, in an eco-friendly adhesive comprising a lignin hydrogel according to the present invention, the lignin hydrogel includes a network structure through the combination of a lignin material and a zwitterionic polymer.

[0009] In addition, in an eco-friendly adhesive comprising a lignin hydrogel according to one embodiment of the present invention, the zwitterionic polymer is selected from the group consisting of 2-(methacryloyloxy)-3-(trimethylammonio) propane-1-sulfonate, 3-pyridinio-2-methacryloyloxypropane-1-sulfonate, arginine methacrylate, 3-N-methylpyrrolidinio-2-methacryloyloxypropane-1-sulfonate, and vinylimidazole-based carboxybetaine polymer. It can be any one of a vinylimidazole-based sulfobetaine polymer (poly(sulfobetaine) based on vinylimidazole).

[0010] Additionally, in an eco-friendly adhesive comprising a lignin hydrogel according to one embodiment of the present invention, the zwitterionic polymer can be physically cross-linked by cation-pi interactions and dipole-dipole interactions on the surface of the lignin.

[0011] In addition, in an eco-friendly adhesive including a lignin hydrogel according to one embodiment of the present invention, when the total weight of the lignin hydrogel is 100 parts by weight, the sum of the weights of the lignin-based material and the zwitterionic polymer may be 10 to 70 parts by weight.

[0012] In addition, in an eco-friendly adhesive including a lignin hydrogel according to one embodiment of the present invention, when the total weight of the lignin hydrogel is 100 parts by weight, the sum of the weights of the lignin-based material and the zwitterionic polymer may be 20 to 50 parts by weight.

[0013] In addition, in an eco-friendly adhesive including a lignin hydrogel according to one embodiment of the present invention, when the total weight of the lignin hydrogel is 100 parts by weight, the sum of the weights of the lignin-based material and the zwitterionic polymer is 10 to 20 parts by weight, and the lignin hydrogel may have viscoelastic properties.

[0014] Additionally, an eco-friendly adhesive comprising a lignin hydrogel according to one embodiment of the present invention may be a bioadhesive.

[0015] In addition, an eco-friendly adhesive including a lignin hydrogel according to one embodiment of the present invention may be a bioadhesive included in a biotransplant device.

[0016] According to the present invention, a method for producing an eco-friendly lignin hydrogel for an adhesive can be provided, comprising the steps of adding lignin, a zwitterionic monomer, and a polymerization initiator to water and mixing them to prepare a mixture, and the step of irradiating the mixture with microwaves.

[0017] Additionally, in the method for producing an eco-friendly adhesive lignin hydrogel according to one embodiment of the present invention, the zwitterionic monomer may be imidazolium sulfobetaine.

[0018] Additionally, in the method for producing an eco-friendly lignin hydrogel for an adhesive according to one embodiment of the present invention, the polymerization initiator may be 2,2′-azobis(2-methylpropionamidine) dihydrochloride.

[0019] In addition, in the method for manufacturing an eco-friendly adhesive lignin hydrogel according to one embodiment of the present invention, when the total weight of the mixture is 100 parts by weight, the sum of the weights of the lignin-based material and the zwitterionic polymer may be 10 to 70 parts by weight.

[0020] In addition, in the method for manufacturing an eco-friendly lignin hydrogel for an adhesive according to one embodiment of the present invention, the microwave irradiation can be maintained for 1 hour or more so that the temperature of the mixture is 60°C or higher.

[0021] According to the present invention, an eco-friendly adhesive comprising a lignin hydrogel having excellent biocompatibility and adhesiveness can be provided.

[0022] In addition, the simple and mass-synthesizable lignin hydrogel manufacturing method provided in the present invention enables the effective and economical production of lignin hydrogel, thereby enabling the production of an eco-friendly adhesive.

[0023] Figure 1 is a drawing showing the structural formula of a zwitterionic polymer of a lignin hydrogel according to an embodiment of the present invention.

[0024] Figure 2 is a schematic diagram illustrating a process for manufacturing a lignin hydrogel according to an embodiment of the present invention.

[0025] Figure 3 is a graph showing the results of evaluating the mechanical properties of a lignin hydrogel according to an embodiment of the present invention.

[0026] Figure 4 is an image showing the results of evaluating the self-healing ability of a lignin hydrogel according to an embodiment of the present invention.

[0027] Figure 5 is a graph showing the results of evaluating the adhesiveness of a lignin hydrogel according to an embodiment of the present invention.

[0028] Figure 6 is an image and graph showing the results of evaluating the adhesiveness of a lignin hydrogel to various objects according to an embodiment of the present invention.

[0029] Figure 7 is a graph showing the results of evaluating the biocompatibility of a lignin hydrogel according to an embodiment of the present invention.

[0030] Figure 8 is a graph showing the results of evaluating the conductivity of a lignin hydrogel according to an embodiment of the present invention.

[0031] Below, with reference to the attached drawings, embodiments of the present invention are described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0032] In addition, in order to clearly explain the invention in the drawings, parts unrelated to the explanation were omitted, and similar drawing symbols were assigned to similar parts throughout the specification.

[0033] The eco-friendly adhesive according to the present invention may include a lignin hydrogel having a network structure through the bonding of lignin and a zwitterionic polymer.

[0034] As described above, lignin possesses biocompatibility and environmental friendliness, making hydrogels using it suitable for eco-friendly adhesives. However, lignin's low dispersibility makes it difficult to hydrogel. In the present invention, this low dispersibility of lignin was overcome by forming a network structure through the binding of zwitterionic polymers.

[0035] In these lignin hydrogels, zwitterionic polymers include 2-(methacryloyloxy)-3-(trimethylammonio) propane-1-sulfonate, 3-pyridinio-2-methacryloyloxypropane-1-sulfonate, arginine methacrylate, 3-N-Methylpyrrolidinio-2-methacryloyloxypropane-1-sulfonate, poly(carboxybetaine) based on vinylimidazole, and vinylimidazole. It can be any one of poly(sulfobetaine) based on vinylimidazole polymers. The structural formula of such polymer is shown in Fig. 1.

[0036] These zwitterionic polymers are physically cross-linked by cation-pi interactions and dipole-dipole interactions on the surface of lignin-based materials containing either or both lignin and lignocellulose to form lignin hydrogels (see Fig. 2).

[0037] In such lignin hydrogels, when the total weight of the lignin hydrogel is 100 parts by weight, the sum of the lignin-based material and the polymer is preferably 10 to 70 parts by weight, and more preferably 20 to 50 parts by weight. If the content of the lignin-based material and the polymer is too low or too high, it becomes difficult to form a network structure for the hydrogel.

[0038] In particular, when the content of lignin-based substances and polymers is 10 to 20 parts by weight, the hydrogel has viscoelastic properties. Even if the conductivity or mechanical properties are inferior to those of hydrogels with a high lignin-based substance content, the hydrogel has viscoelastic properties, and an eco-friendly adhesive can be manufactured using these properties.

[0039] The lignin hydrogel according to the present invention can be an eco-friendly adhesive applicable to a variety of fields. In particular, it is non-toxic to the human body and possesses high bioadhesive strength, making it highly advantageous for use as a bioadhesive for wound healing and other applications.

[0040] The method for producing such a lignin hydrogel may include a step of preparing a mixture by adding and mixing a lignin-based material, a zwitterionic monomer, and a polymerization initiator into water, and a step of irradiating the mixture with microwaves.

[0041] At this time, the zwitterionic monomer may be imidazolium sulfobetaine, which allows for easy formation of lignin hydrogel using microwave irradiation.

[0042] Additionally, the polymerization initiator can be 2,2′-azobis(2-methylpropionamidine) dihydrochloride.

[0043] Meanwhile, in the method for producing a lignin hydrogel, the weight of the mixture may be 100 parts by weight, and the sum of the weights of the lignin-based material and the zwitterionic polymer may be included in an amount of 10 to 70 parts by weight. If the content of the lignin-based material is too low or too high, it becomes difficult to smoothly form a hydrogel.

[0044] Additionally, the microwave irradiation can be maintained for more than one hour so that the temperature of the mixture is 60°C or higher.

[0045]

[0046] [Example]

[0047] Lignin hydrogel was prepared by dispersing lignin, SBVI monomer, and V-50 initiator (0.05 mmol) in 15 ml of deionized water to form a mixture. The mixture was transferred to a microwave reaction vessel, tightly sealed, and then microwaved. The reaction was heated to 80°C within 30 min and maintained at 80°C for 2 h.

[0048]

[0049] Preparation of materials

[0050] Lignin, 2,2′-azobis(2-methylpropionamidine) dihydrochloride (initiator, Sigma-Aldrich, V-50), and imidazolium sulfobetaine (SBVI) were prepared.

[0051]

[0052] Synthesis of lignin hydrogel via microwave synthesis

[0053] Lignin (0.1, 0.2, 0.3, 0.4, and 0.5 g), SBVI monomer (1.4, 2.8, 4.2, 5.6, and 7.0 g), and V-50 initiator (0.05 mmol) were dispersed in 15 mL of deionized water. The dispersed mixture was transferred to a microwave reaction vessel, tightly sealed, and the reaction was initiated. The reaction was heated to 80°C within 30 min and maintained at 80°C for 2 h. The sample names of the prepared lignin hydrogels were named according to the lignin and SBVI contents, as shown in Table 1 below.

[0054]

[0055] Sample name Lig1 Lig2 Lig3 Lig4 Lig5 Lignin (g) 0.1 0.2 0.3 0.4 0.5 SBVI (g) 1.4 2.8 4.2 5.6 7.0 w / v % 10% 20% 30% 40% 50%

[0056]

[0057] mechanical properties

[0058] The mechanical properties of the lignin hydrogels were measured using a rheometer (T-1040, TA instrument) with a 20 mm diameter parallel plate. The elastic modulus of the hydrogels was measured at a frequency of 1–100 rad / s at 1% strain.

[0059]

[0060] Conductivity test

[0061] The conductivity of the lignin hydrogel was measured using a two-electrode method using EIS (WizEIS-1200 premium, WizMAC). The hydrogel was placed between aluminum foil with a 1 mm silicone mold to block contact between the two electrodes. Hz ~ Frequency sweeps were measured in Hz.

[0062]

[0063] Adhesion test

[0064] The adhesive properties of the lignin hydrogel were determined by superimposed shear testing using a universal testing machine (INSTRON 5848, INSTRON). The lignin hydrogel was evenly spread between two pig skins (10 mm Х10 mm Х1 mm) and measured at a shear rate of 10 mm / min at room temperature.

[0065]

[0066] Figure 3 shows the results of an evaluation of the mechanical properties of the prepared lignin hydrogel. The viscoelasticity can be controlled by varying the concentration of lignin and monomer, thereby ensuring mechanical properties similar to those of biological tissues. The low-concentration sample, Lig1, and the high-concentration sample, Lig5, exhibited distinctly different viscoelastic properties.

[0067] Figure 4 demonstrates the self-healing properties of lignin hydrogel. Self-healing was observed even after cutting, and mechanical properties were maintained thereafter.

[0068] Figure 5 is a graph showing the results of adhesive strength evaluation. Adhesion can be imparted through interactions between functional groups present in lignin hydrogel and functional groups present in skin. Actual adhesion experiments showed adhesion more than five times higher than that of conventional bioadhesives (CG).

[0069] Figure 6 shows that it exhibits high adhesive strength for various objects other than living organisms.

[0070] Figure 7 shows the results of an evaluation of the potential of the lignin hydrogel according to the present invention to be incorporated into a bio-implantable device. The lignin hydrogel used in this example demonstrated no hemolysis, and in vitro cytotoxicity testing confirmed the absence of cytotoxicity. Furthermore, wounds treated with the lignin hydrogel showed faster healing rates than those treated with the control group.

[0071] Figure 8 shows the conductivity results of lignin hydrogels measured using four-terminal resistance measurements. It was observed that electrical conductivity increased with increasing lignin content. This suggests potential applications in neurostimulation medical devices and sensors.

Claims

1. An eco-friendly adhesive containing lignin hydrogel, An eco-friendly adhesive comprising a lignin hydrogel, wherein the lignin hydrogel comprises a network structure formed through a combination of a lignin-based material and a zwitterionic polymer, and the lignin-based material comprises either one or both of lignin and lignocellulose.

2. In paragraph 1, The above zwitterionic polymers are 2-(methacryloyloxy)-3-(trimethylammonio) propane-1-sulfonate, 3-pyridinio-2-methacryloyloxypropane-1-sulfonate, arginine methacrylate, 3-N-Methylpyrrolidinio-2-methacryloyloxypropane-1-sulfonate, poly(carboxybetaine) based on vinylimidazole, sulfobetaine based on vinylimidazole. An eco-friendly adhesive containing lignin hydrogel, which is one of the polymers (poly(sulfobetaine) based on vinylimidazole).

3. In paragraph 1, An eco-friendly adhesive comprising a lignin hydrogel, wherein the above-mentioned zwitterionic polymer is physically cross-linked by cation-pi interactions and dipole-dipole interactions on the surface of the lignin-based material.

4. In paragraph 1, An eco-friendly adhesive including a lignin hydrogel, wherein the sum of the weights of the lignin-based material and the zwitterionic polymer is 10 to 70 parts by weight when the total weight of the lignin hydrogel is 100 parts by weight.

5. In paragraph 4, An eco-friendly adhesive including a lignin hydrogel, wherein when the total weight of the lignin hydrogel is 100 parts by weight, the sum of the weights of the lignin-based material and the zwitterionic polymer is 20 to 50 parts by weight.

6. In paragraph 4, An eco-friendly adhesive comprising a lignin hydrogel, wherein when the total weight of the lignin hydrogel is 100 parts by weight, the sum of the weights of the lignin-based material and the zwitterionic polymer is 10 to 20 parts by weight, and the lignin hydrogel has viscoelastic properties.

7. In paragraph 1, The above eco-friendly adhesive is an eco-friendly adhesive containing lignin hydrogel, which is a bio-adhesive.

8. In paragraph 7, The above bioadhesive is an eco-friendly adhesive containing lignin hydrogel, which is included in a bioimplantation device.

9. A method for producing an eco-friendly lignin hydrogel for an adhesive, comprising the steps of adding lignin or lignocellulose and a zwitterionic monomer and a polymerization initiator to water and mixing them to prepare a mixture, and the step of irradiating the mixture with microwaves.

10. In paragraph 9, A method for producing an eco-friendly lignin hydrogel for adhesives, wherein the above-mentioned zwitterionic monomer is imidazolium hydrobetaine.

11. In Article 10, A method for producing an eco-friendly lignin hydrogel for an adhesive, wherein the polymerization initiator is 2,2′-azobis(2-methylpropionamidine) dihydrochloride.

12. In paragraph 9, A method for producing an eco-friendly lignin hydrogel for an adhesive, wherein the sum of the weights of the lignin-based material and the zwitterionic polymer is 10 to 70 parts by weight when the total weight of the mixture is 100 parts by weight.

13. In paragraph 9, A method for producing an eco-friendly adhesive lignin hydrogel, wherein the microwave irradiation is performed so that the temperature of the mixture is 60° C. or higher and maintained for 1 hour or longer.

Images