Environmentally friendly adhesive comprising a lignin hydrogel and method for manufacturing environmentally friendly lignin hydrogel

Abstract

The present invention aims to provide an eco-friendly and economical eco-friendly adhesive using a lignin hydrogel. To achieve the above-described object, in the eco-friendly adhesive comprising a lignin hydrogel according to the present invention, the above-described lignin hydrogel comprises a network structure formed by combining lignin with a zwitterionic polymer.

Description

Technical Field

[0001] This invention relates to an environmentally friendly adhesive comprising lignin hydrogel, particularly characterized by the lignin hydrogel comprising a network structure formed by combining lignin-like substances with zwitterionic polymers. Background Technology

[0002] In recent years, the development of environmentally friendly adhesives has been very active. Environmentally friendly adhesives are designed to minimize negative impacts on the environment and human health, and can be applied in various fields such as cosmetics, food packaging materials, and biodegradable adhesives.

[0003] Especially among environmentally friendly adhesives, bioadhesives refer to adhesives that can adhere to biological tissues. They are widely used in medical applications, including wound healing, tissue regeneration, and drug delivery. Materials used as bioadhesives primarily employ protein-based, polysaccharide-based, and synthetic polymer-based materials, requiring properties such as biocompatibility, adhesive strength, biodegradability, and flexibility.

[0004] On the other hand, lignin is one of the three main components of plant cell walls and the second most abundant plant macromolecule on Earth. Lignin is not only abundant in nature but is also a significant byproduct of the pulp and paper industry. The annual production of lignin produced in this way reaches approximately 50 million tons, but in reality, most of it is discarded or used as fuel.

[0005] In recent years, in order to utilize the environmental and economic value of lignin, which has biocompatibility, environmental friendliness, and low toxicity, research is being conducted on production methods for high-value-added functional materials such as bioplastics, adhesives, and dispersion materials. However, due to the irregular structure of lignin and its difficulty in mixing with other substances, it is still rarely used in actual industries. Summary of the Invention

[0006] Technical issues

[0007] The purpose of this invention is to provide an environmentally friendly and economical adhesive that utilizes lignin hydrogels.

[0008] In addition, the aim is to provide a method for manufacturing lignin hydrogels for environmentally friendly adhesives that can be easily and economically mass-produced.

[0009] Solution to the problem

[0010] In order to achieve the objectives described above, in the environmentally friendly adhesive containing lignin hydrogel according to the present invention, the lignin hydrogel comprises a network structure formed by combining lignin material with zwitterionic polymer.

[0011] Additionally, in an environmentally friendly adhesive comprising lignin hydrogel according to an embodiment of the present invention, the aforementioned zwitterionic polymer may be 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, or poly(sulfobetaine) based on vinylimidazole. Any of the following: vinylimidazole.

[0012] Furthermore, in an environmentally friendly adhesive containing lignin hydrogel according to an embodiment of the present invention, the aforementioned zwitterionic polymer can be physically crosslinked on the surface of the lignin through cation-π interactions and dipole-dipole interactions.

[0013] In addition, in an environmentally friendly adhesive containing lignin hydrogel according to an embodiment of the present invention, the sum of the weights of the lignin-like substances and the zwitterionic polymers can be 10 to 70 parts by weight, based on a total weight of 100 parts by weight of the lignin hydrogel.

[0014] In addition, in an environmentally friendly adhesive containing lignin hydrogel according to an embodiment of the present invention, the sum of the weights of the lignin-like substances and the zwitterionic polymers can be 20 to 50 parts by weight, based on a total weight of 100 parts by weight of the lignin hydrogel.

[0015] In addition, in an environmentally friendly adhesive containing lignin hydrogel according to an embodiment of the present invention, based on 100 parts by weight of the total weight of the lignin hydrogel, the sum of the weights of the lignin-like substances and the zwitterionic polymer is 10 to 20 parts by weight, and the lignin hydrogel may have viscoelastic properties.

[0016] In addition, according to one embodiment of the present invention, the environmentally friendly adhesive containing lignin hydrogel can be an adhesive for use in living organisms.

[0017] In addition, according to one embodiment of the present invention, the environmentally friendly adhesive containing lignin hydrogel can be a bio-adhesive included in a bio-implantation element.

[0018] According to the present invention, a method for manufacturing lignin hydrogel for environmentally friendly adhesives can be provided, comprising: adding lignin, zwitterionic monomers and polymerization initiators into water and mixing them to prepare a mixture; and irradiating the mixture with microwaves.

[0019] In addition, in a method for manufacturing lignin hydrogels for environmentally friendly adhesives according to an embodiment of the present invention, the aforementioned zwitterionic monomer may be imidazolyl sulfobetaine.

[0020] In addition, in a method for manufacturing lignin hydrogel for environmentally friendly adhesives according to an embodiment of the present invention, the polymerization initiator may be 2,2′-azobis(2-methylpropanediamine) dihydrochloride.

[0021] In addition, in a method for manufacturing lignin hydrogel for environmentally friendly adhesives according to an embodiment of the present invention, the sum of the weights of the lignin-like substances and the zwitterionic polymers can be 10 to 70 parts by weight, based on a total weight of 100 parts by weight of the mixture.

[0022] In addition, in a method for manufacturing lignin hydrogel for environmentally friendly adhesives according to an embodiment of the present invention, the microwave irradiation can raise the temperature of the mixture to 60°C or higher and maintain it for more than 1 hour.

[0023] Invention Effects

[0024] According to the present invention, an environmentally friendly adhesive comprising a lignin hydrogel with excellent biocompatibility and adhesive properties can be provided.

[0025] Furthermore, the simple and mass-producible lignin hydrogel manufacturing method provided in this invention enables the efficient and economical production of lignin hydrogels, thereby creating environmentally friendly adhesives. Attached Figure Description

[0026] Figure 1 This is a diagram illustrating the structural formula of a zwitterionic polymer of lignin hydrogel according to an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram illustrating the manufacturing process of lignin hydrogel according to an embodiment of the present invention.

[0028] Figure 3 This is a graph showing the results of evaluating the mechanical properties of lignin hydrogels according to embodiments of the present invention.

[0029] Figure 4 This is an image showing the results of evaluating the self-healing ability of a lignin hydrogel according to an embodiment of the present invention.

[0030] Figure 5 This is a graph showing the results of evaluating the adhesiveness of lignin hydrogels according to embodiments of the present invention.

[0031] Figure 6 These are images and graphs showing the results of evaluating the adhesion of lignin hydrogels according to embodiments of the present invention to various objects.

[0032] Figure 7 This is a graph showing the results of evaluating the biocompatibility of lignin hydrogels according to embodiments of the present invention.

[0033] Figure 8 This is a graph showing the results of evaluating the electrical conductivity of the lignin hydrogel according to an embodiment of the present invention. Detailed Implementation

[0034] Hereinafter, embodiments of this application will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement the application. However, this application can be implemented in many different forms and is not limited to the embodiments described herein.

[0035] In addition, in order to clearly illustrate this application, parts that are not related to the description have been omitted, and similar reference numerals have been used to mark similar parts throughout the specification.

[0036] The environmentally friendly adhesives according to the present invention may include lignin hydrogels comprising a network structure formed by combining lignin with zwitterionic polymers.

[0037] As mentioned above, lignin possesses biocompatibility and environmental friendliness, making lignin-based hydrogels suitable for use as environmentally friendly adhesives. However, the low dispersibility of lignin presents a challenge in achieving hydrogelation. In this invention, the low dispersibility of lignin is addressed by forming a network structure through the combination of zwitterionic polymers.

[0038] In this lignin hydrogel, the zwitterionic polymer can be any one of 2-(methacryloyloxy)-3-(trimethylammonio)propane-1-sulfonate, 3-Pyridinio-2-methacryloyloxypropane-1-sulfonate, argininemethacrylate, 3-N-Methylpyrrolidinio-2-methacryloyloxypropane-1-sulfonate, poly(carboxybetaine) based on vinylimidazole, and poly(sulfobetaine) based on vinylimidazole. The structural formula of this polymer is shown in Figure 1 .

[0039] This zwitterionic polymer physically crosslinks on the surface of any one or both of the lignin-like substances, including lignin or lignocellulose, through cation-π interactions and dipole-dipole interactions, thereby forming a lignin hydrogel (see reference). Figure 2 ).

[0040] In this lignin hydrogel, the sum of lignin and polymer is preferably 10 to 70 parts by weight, more preferably 20 to 50 parts by weight, based on 100 parts by weight of the total lignin hydrogel. If the content of lignin and polymer is too low or too high, it is difficult to form a network structure for the hydrogel.

[0041] In particular, when the content of lignin and polymer is 10 to 20 parts by weight, the hydrogel has viscoelastic properties. Although its electrical conductivity or mechanical properties are not as good as those of hydrogels with high lignin content, it has viscoelastic properties and can be used to manufacture environmentally friendly adhesives that utilize these properties.

[0042] The lignin hydrogel according to the present invention can be an environmentally friendly adhesive applicable to a variety of fields. In particular, due to its non-toxicity to humans and high bioadhesive strength, it can be very advantageously used as a bioadhesive for applications such as wound treatment.

[0043] The method for manufacturing this lignin hydrogel may include: the step of adding lignin-like substances, zwitterionic monomers, and polymerization initiators into water and mixing them to prepare a mixture; and the step of irradiating the mixture with microwaves.

[0044] In this case, the zwitterionic monomer can be imidazolyl sulfobetaine, which allows for the easy formation of lignin hydrogels using microwave irradiation.

[0045] Alternatively, the polymerization initiator can be 2,2′-azobis(2-methylpropanediamine) dihydrochloride.

[0046] On the other hand, in the method for manufacturing lignin hydrogels, the sum of the weights of the lignin-like substances and the zwitterionic polymers can be 10 to 70 parts by weight, based on 100 parts by weight of the mixture. If the content of the lignin-like substances is too low or too high, it will be difficult to form a hydrogel smoothly.

[0047] In addition, microwave irradiation can raise the temperature of the mixture to above 60°C and maintain it for more than 1 hour.

[0048] [Example]

[0049] For the lignin hydrogel, lignin, SBVI monomer, and V-50 initiator (0.05 mmol) were dispersed in 15 ml of deionized water to prepare a mixture, which was then transferred to a microwave reaction vessel, tightly sealed, and subjected to microwave irradiation. The reaction was heated to 80 °C within 30 minutes and then maintained at 80 °C for 2 hours.

[0050] Material preparation

[0051] Prepare lignin, 2,2′-azobis(2-methylpropanediamine) dihydrochloride (initiator, Sigma-Aldrich, V-50), and imidazolyl sulfobetaine (SBVI).

[0052] Synthesis of lignin hydrogels via microwave synthesis

[0053] Lignin (0.1 g, 0.2 g, 0.3 g, 0.4 g, 0.5 g) and SBVI monomer (1.4 g, 2.8 g, 4.2 g, 5.6 g, 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, sealed tightly, and the reaction was initiated. The reaction was heated to 80 °C within 30 minutes and then maintained at 80 °C for 2 hours. The samples of the prepared lignin hydrogels were named according to the lignin and SBVI contents as shown in Table 1 below.

[0054] [Table 1]

[0055] Mechanical properties

[0056] The mechanical properties of the lignin hydrogel were measured using a rheometer (T-1040, TA instrument) equipped with a parallel plate with a diameter of 20 mm. The elastic modulus of the hydrogel was measured at 1% strain at frequencies ranging from 1 to 100 rad / s.

[0057] Conductivity test

[0058] The electrical conductivity of the lignin hydrogel was confirmed using an EIS (WizEIS-1200 premium, WizMAC) in a two-electrode configuration. The hydrogel was placed between aluminum foils with a 1 mm silicone mold to prevent contact between the two electrodes, and conductivity was measured in the range of 0.1 Hz to 10 Hz. 6 Frequency scanning was measured at Hz.

[0059] Adhesion test

[0060] The adhesive properties of the lignin hydrogel were confirmed using an lap shear test on a universal testing machine (INSTRON 5848, INSTRON). The lignin hydrogel was uniformly applied between two pieces of pigskin (10 mm × 10 mm × 1 mm), and then measured at a shear rate of 10 mm / min at room temperature.

[0061] Figure 3 These are the results of the mechanical property evaluation of the prepared lignin hydrogels. The viscoelasticity can be adjusted according to the concentration of lignin and monomers, thereby ensuring similar mechanical properties according to biological tissues. It can be seen that the sample Lig1 with a lower concentration and the sample Lig5 with a higher concentration exhibit distinctly different viscoelastic properties.

[0062] Figure 4 The self-healing properties of the lignin hydrogel are shown. It can be seen that it self-heals even after being cut, and its mechanical properties are subsequently maintained.

[0063] Figure 5 This is a chart showing the results of evaluating adhesive strength. Adhesive strength is imparted through the interaction between functional groups present in the lignin hydrogel and those present in the skin. Actual adhesion experiments show that its adhesive strength is more than 5 times higher than existing bioadhesives (CG).

[0064] Figure 6 The results show that, in addition to biological objects, it also exhibits high adhesion to a variety of other objects.

[0065] Figure 7This is the result of an evaluation of the possibility that the lignin hydrogel according to the present invention can be included in biological transplantation elements. It was confirmed that no hemolysis occurred in the lignin hydrogel of this embodiment, and in vitro cytotoxicity tests confirmed no cytotoxicity. Furthermore, it was confirmed that wounds treated with the lignin hydrogel healed faster than the control group.

[0066] Figure 8 The conductivity results of the lignin hydrogel, measured by four-terminal resistance, are shown. It can be seen that the higher the lignin content, the higher the conductivity. Therefore, it is expected to be applicable to medical devices and sensors for nerve stimulation.

Claims

1. An environmentally friendly adhesive comprising lignin hydrogel, wherein, The aforementioned lignin hydrogel comprises a network structure formed by combining lignin-like substances with zwitterionic polymers, wherein the lignin-like substances include any one or both of lignin and lignocellulose.

2. The environmentally friendly adhesive comprising lignin hydrogel according to claim 1, wherein, The aforementioned zwitterionic polymer is any one of 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 Poly(sulfobetaine) based on vinylimidazole.

3. The environmentally friendly adhesive comprising lignin hydrogel according to claim 1, wherein, The aforementioned zwitterionic polymers undergo physical cross-linking on the surface of the aforementioned lignin-based substances through cation-π interactions and dipole-dipole interactions.

4. The environmentally friendly adhesive comprising lignin hydrogel according to claim 1, wherein, Based on a total weight of 100 parts by weight of the lignin hydrogel, the sum of the weights of the lignin-like substances and the zwitterionic polymers is 10 to 70 parts by weight.

5. The environmentally friendly adhesive comprising lignin hydrogel according to claim 4, wherein, Based on a total weight of 100 parts by weight of the lignin hydrogel, the sum of the weights of the lignin-like substances and the zwitterionic polymers is 20 to 50 parts by weight.

6. The environmentally friendly adhesive comprising lignin hydrogel according to claim 4, wherein, Based on a total weight of 100 parts by weight of the lignin hydrogel, the sum of the weights of the lignin-like substances and the zwitterionic polymer is 10 to 20 parts by weight, and the lignin hydrogel has viscoelastic properties.

7. The environmentally friendly adhesive comprising lignin hydrogel according to claim 1, wherein, The aforementioned environmentally friendly adhesives are adhesives for use in living organisms.

8. The environmentally friendly adhesive comprising lignin hydrogel according to claim 7, wherein, The aforementioned biological adhesive is included in biological transplantation elements.

9. A method for manufacturing lignin hydrogel for an environmentally friendly adhesive, comprising: The step of adding lignin or lignocellulose to water and mixing with zwitterionic monomers and polymerization initiators to prepare a mixture; The step of microwave irradiating the mixture described above.

10. The method for manufacturing lignin hydrogel for environmentally friendly adhesives according to claim 9, wherein, The aforementioned zwitterionic monomer is imidazolium sulfobetaine.

11. The method for manufacturing lignin hydrogel for environmentally friendly adhesives according to claim 10, wherein, The polymerization initiator mentioned above is 2,2′-azobis(2-methylpropanediamine) dihydrochloride.

12. The method for manufacturing lignin hydrogel for environmentally friendly adhesives according to claim 9, wherein, Based on a total weight of 100 parts by weight of the above mixture, the sum of the weights of the above lignin-like substances and the above zwitterionic polymers is 10 to 70 parts by weight.

13. The method for manufacturing lignin hydrogel for environmentally friendly adhesives according to claim 9, wherein, The microwave irradiation caused the temperature of the mixture to reach above 60°C and was maintained for more than 1 hour.

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