A wood adhesive based on microcrystalline cellulose for capturing carbon dioxide and a preparation method and application thereof

Abstract

The present application belongs to the technical field of adhesives, and particularly relates to a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide as well as a preparation method and application thereof. The present application first mixes microcrystalline cellulose, 1,8-diazabicyclo[5.4.0]undec-7-ene, dimethyl sulfoxide and water, introduces carbon dioxide gas into the obtained reaction solution under oil bath conditions to perform an activation reaction, second mixes the obtained MCC@CO2 slurry, chitosan and a phenolic enhancer (or without adding the phenolic enhancer) to perform heating and dissolution, adds acid into the obtained mixture to adjust the pH value, and obtains the wood adhesive based on microcrystalline cellulose for capturing carbon dioxide. The wood adhesive based on microcrystalline cellulose for capturing carbon dioxide has a low curing temperature, excellent bonding strength, stability and water resistance, and the prepared plywood meets the requirements (wet strength ≥ 0.7 MPa) of GB / T 9846-2015 on the type II plywood.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide, its preparation method, and its application. Background Technology

[0002] Currently, the widely used industrial processes for preparing cellulose nanofibers often involve multiple chemical purification steps, including pulping, bleaching, and washing. These processes are not only time-consuming and water-intensive, but also release large amounts of adsorbable organic halogens (AOX), volatile organic compounds (VOCs), and chlorophenols. Wastewater treatment is difficult and energy-intensive, which has become a key issue restricting the green upgrading of industries.

[0003] To address the challenges of cellulose dissolution and homogeneous modification, researchers have developed various solvent systems, such as N-methylmorpholine N-oxide (NMMO), N,N-dimethylacetamide / lithium chloride (DMAc-LiCl), and dimethyl sulfoxide / tetrabutylammonium fluoride (DMSO-TBAF). However, these systems generally suffer from high solvent toxicity, difficult recovery, strong equipment corrosivity, and harsh reaction conditions, limiting their large-scale application.

[0004] With increasing global emphasis on sustainable materials and a low-carbon economy, the development of high-performance, environmentally friendly biomass-based wood adhesives has become a research hotspot. Currently, common biomass adhesives include starch-based, protein-based, lignin-based, and cellulose-based adhesives, but they generally suffer from poor water resistance, low bond strength, high curing temperature, and insufficient stability. These issues make it difficult to meet national standards for Class II and above plywood (such as the requirement of wet strength ≥0.7 MPa in GB / T 9846-2015), thus limiting their widespread application in the wood-based panel industry. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide, its preparation method and application. The wood adhesive based on microcrystalline cellulose for capturing carbon dioxide provided by this invention has a low curing temperature, excellent bonding strength, stability and water resistance, and the plywood prepared meets the requirements of GB / T 9846-2015 for Class II plywood (wet strength ≥0.7MPa).

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide, comprising the following steps: Microcrystalline cellulose, 1,8-diazabicyclo[5.4.0]undec-7-ene, dimethyl sulfoxide and water were mixed first, and carbon dioxide gas was introduced into the resulting reaction solution under oil bath conditions to carry out the activation reaction, so as to obtain MCC@CO2 slurry; The MCC@CO2 slurry, chitosan and phenolic reinforcing agent are heated and dissolved. Acid is added to the resulting mixture to adjust the pH value to 4-7, thereby obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide. Alternatively, the MCC@CO2 slurry and chitosan are mixed and heated to dissolve. An acid is added to the resulting mixture to adjust the pH to 4-7, thus obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide.

[0007] Preferably, the mass ratio of the microcrystalline cellulose to the volume ratio of 1,8-diazabicyclo[5.4.0]undec-7-ene is (1~2) g:(400~800) μL; and the mass ratio of the microcrystalline cellulose to the volume ratio of dimethyl sulfoxide is (1~2) g:(2~4) mL.

[0008] Preferably, the temperature of the oil bath is 35~65℃; and the activation reaction time is 8~24h.

[0009] Preferably, the phenolic enhancer includes one or more of hydroquinone, phenol, and phloroglucinol.

[0010] Preferably, the mass ratio of microcrystalline cellulose to chitosan is 1~2:2~4.

[0011] Preferably, the mass ratio of chitosan to phenolic reinforcing agent is 1~6:0.2~1.

[0012] Preferably, the acid is glacial acetic acid.

[0013] The present invention also provides a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide prepared by the preparation method described in the above technical solution.

[0014] The present invention also provides the application of the microcrystalline cellulose-based carbon dioxide capture wood adhesive described above in the preparation of wood panels.

[0015] The present invention also provides a method for preparing plywood, comprising the following steps: After applying adhesive to the veneer, multiple layers of veneers are combined and hot-pressed to obtain plywood. The adhesive is the wood adhesive based on microcrystalline cellulose for capturing carbon dioxide described in the above technical solution.

[0016] This invention provides a method for preparing a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide, comprising the following steps: Microcrystalline cellulose, 1,8-diazabicyclo[5.4.0]undec-7-ene, dimethyl sulfoxide and water were mixed first, and carbon dioxide gas was introduced into the resulting reaction solution under oil bath conditions to carry out the activation reaction, so as to obtain MCC@CO2 slurry; The MCC@CO2 slurry, chitosan and phenolic reinforcing agent are heated and dissolved. Acid is added to the resulting mixture to adjust the pH value to 4-7, thereby obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide. Alternatively, the MCC@CO2 slurry and chitosan are mixed and heated to dissolve. An acid is added to the resulting mixture to adjust the pH to 4-7, thus obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide.

[0017] The beneficial effects of this invention are as follows: 1. Environmentally friendly and green process: Traditional cellulose modification (such as oxidation) is costly and polluting, while this invention uses CO2 as the core reactant and crosslinking agent, utilizing greenhouse gas to achieve carbon fixation and resource utilization, reducing the use and emission of harmful chemicals (such as AOX and VOCs) from the source.

[0018] 2. Simplified process and improved efficiency: This invention overcomes the difficulties of traditional cellulose dissolution and derivatization, which require specialized solvents, complex steps, and cumbersome post-processing. The invention optimizes the DMSO / DBU / H2O system, achieving a one-step preparation method that eliminates the need for separation and purification of modified cellulose, directly yielding the adhesive precursor solution. The process is simple and conducive to large-scale production (it has already demonstrated potential for 50kg-level production).

[0019] 3. Excellent Product Performance: The prepared microcrystalline cellulose-based carbon dioxide capture wood adhesive has a low curing temperature, exhibiting excellent bonding strength, stability, and outstanding water resistance. For example, the MCC@CO2-CS / HQ adhesive still maintains a wet strength of 1.42 MPa after boiling water treatment for 3 hours, exceeding the requirements of the national standard GB / T 9846-2015 for Class II plywood (wet strength ≥ 0.7 MPa). Simultaneously, the high wood breakage rate (approximately 50% after boiling water treatment) indicates a strong bond between the adhesive and the wood interface.

[0020] reason: 1. Successful CO2 capture and in-situ introduction of carboxyl groups: Following the CO2 reaction, carboxylic acid (-COOH) or carbonate groups were successfully introduced onto the cellulose chains. New O=CO bonds appeared in the modified material, and the oxygen content increased significantly. This directly stems from the chemical reaction between CO2 and cellulose under DBU conditions. This key technological point gives the method the advantages of being environmentally friendly (utilizing CO2) and having a simplified process (one-step activation). The introduced active carboxyl groups form the basis for subsequent cross-linking reactions.

[0021] 2. Formation of a dense three-dimensional covalently cross-linked network: The active groups (such as carboxylic acid derivatives) introduced by CO2 on cellulose undergo effective amidation or Schiff base covalent cross-linking reactions with the amino groups (-NH2) on chitosan, forming stable chemical bonds such as "C=N" or "-CONH-". This dense covalent cross-linking network is the fundamental reason for the adhesive's high wet shear strength, excellent water resistance, and solvent stability. Compared to physical interactions such as hydrogen bonding, covalent bonds resist water molecule intrusion, resulting in significantly superior performance compared to unmodified samples. Attached Figure Description

[0022] Figure 1 Figure A shows a schematic diagram of microcrystalline cellulose capturing carbon dioxide; Figure B shows a schematic diagram of the preparation process and molecular structure of MCC@CO2-CS / HQ adhesive; Figure C shows a demonstration diagram of wood board sample preparation and adhesive performance evaluation; Figure D shows a comparative analysis of the shear strength of the developed MCC@CO2-CS / HQ adhesive with previously reported adhesives (CT@BNNSs / CS / SM adhesive, TA-PDMI-4%BA adhesive, UF-lignin adhesive, P-OS-M25 adhesive, starch adhesive, SP / MCN / DPL@VA adhesive, SM / BD / 5% HPFC adhesive, TA-PA6N adhesive, and OS-AC adhesive). Figure 2 A detailed process diagram of the preparation of MCC@CO2-CS / HQ adhesive from raw materials to final processing; Figure 3 Image A shows SEM images of MCC raw materials, MCC capturing carbon dioxide (MCC@CO2), and MCC@CO2-CS / HQ adhesive; Image B shows SEM images of glue lines and glue nails on a (dry) wood board sample; Image C shows SEM images of glue lines and glue nails on a (wet) wood board sample. Figure 4In the image, A represents the FT-IR curves of MCC and MCC@CO2, B represents the FT-IR curves of MCC-CS / HQ and MCC@CO2-CS / HQ adhesives, C represents the XPS spectra of MCC-CS / HQ and MCC@CO2-CS / HQ adhesives, DF represents the high-resolution spectra of C1s, N1s, and O1s in MCC@CO2-CS / HQ adhesive, and GI represents the high-resolution spectra of C1s, N1s, and O1s in MCC-CS / HQ adhesive. Figure 5 In the diagram, A is the XPS spectrum of MCC and MCC@CO2, B is the high-resolution spectrum of C1s in MCC, C is the high-resolution spectrum of C1s in MCC@CO2, and D is a comparison of different bond energies between MCC and MCC@CO2. Figure 6 A, B, and C represent the DSC curves of adhesives prepared from MCC-CS, MCC@CO2-CS, phenol, hydroquinone, and phloroglucinol, respectively. D compares the curing temperatures of the three adhesive systems. E compares the interfacial bonding distances measured by X-ray scattering or supplementary structural analysis. F is a schematic diagram illustrating the intermolecular spacing regulation caused by different quinone comonomers. G and H are the TG and DTG curves of MCC@CO2-CS / PN, MCC@CO2-CS / HQ, and MCC@CO2-CS / PG adhesives, highlighting thermal stability and decomposition kinetics. I represents the proposed binding mechanism of the MCC@CO2-CS / HQ adhesive, emphasizing quinone-mediated covalent crosslinking and hydrogen bond enhancement. Figure 7 The DSC curve is for an adhesive containing 8 wt% pure chitosan. Figure 8 TGA curve for adhesive containing 8 wt% pure chitosan; Figure 9 DTG curve for adhesive containing 8 wt% pure chitosan; Figure 10 Figures A and B show the mechanical properties of MCC-CS adhesive and MCC@CO2-CS adhesive with phenol, hydroquinone, and phloroglucinol under different conditions. Figure C shows the wood failure rate of three-layer board samples prepared with MCC-CS / HQ adhesive and MCC@CO2-CS / HQ adhesive after being treated with cold water for 24 hours, hot water for 3 hours, and boiling water for 3 hours, respectively. Figure D shows the residual rate and moisture absorption value of MCC-CS, MCC@CO2-CS / PN, MCC@CO2-CS / HQ, and MCC@CO2-CS / PG. Figure E shows the performance comparison of samples after high-temperature curing after soaking in water for 30 days and soaking in DMSO for 30 days. Figure 11 A comparison of the shear strength of MCC and 8wt% pure chitosan adhesive. Detailed Implementation

[0023] This invention provides a method for preparing a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide, comprising the following steps: Microcrystalline cellulose, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), dimethyl sulfoxide (DMSO) and water were first mixed, and carbon dioxide gas was introduced into the resulting reaction solution under oil bath conditions to carry out the activation reaction, thereby obtaining MCC@CO2 slurry; The MCC@CO2 slurry, chitosan and phenolic reinforcing agent are heated and dissolved. Acid is added to the resulting mixture to adjust the pH value to 4-7, thereby obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide. Alternatively, the MCC@CO2 slurry and chitosan are mixed and heated to dissolve. An acid is added to the resulting mixture to adjust the pH to 4-7, thus obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide.

[0024] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0025] In this invention, microcrystalline cellulose, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), dimethyl sulfoxide (DMSO) and water are first mixed, and carbon dioxide gas is introduced into the resulting reaction solution under oil bath conditions to carry out an activation reaction, thereby obtaining MCC@CO2 slurry.

[0026] In one embodiment, the mass ratio of the microcrystalline cellulose to the volume ratio of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is (1~2) g:(400~800) μL, and in a specific embodiment it is 2 g:800 μL; the mass ratio of the microcrystalline cellulose to the volume ratio of dimethyl sulfoxide (DMSO) is (1~2) g:(2~4) mL, and in a specific embodiment it is 2 g:4 mL; the mass ratio of the microcrystalline cellulose to the volume ratio of water is (1~2) g:(19~40) mL, and in a specific embodiment it is 2 g:38 mL.

[0027] In one embodiment, the first mixing is carried out under stirring conditions; the stirring is mechanical stirring; the stirring rate is 500~1000 r / min, specifically 600 r / min in this embodiment, and the time is 8~24 h, specifically 12 h in this embodiment; the temperature of the oil bath is 35~65℃, specifically 45℃ in this embodiment; the activation reaction time is 8~24 h, specifically 12 h in this embodiment; and carbon dioxide gas is introduced to maintain gentle bubbling and ensure a CO2 atmosphere.

[0028] Microcrystalline cellulose is activated by CO2 and DBU to form soluble or highly dispersed MCC@CO2 slurry.

[0029] After obtaining the MCC@CO2 slurry, the present invention heats and dissolves the MCC@CO2 slurry, chitosan and phenolic reinforcing agent in a second mixture, adds acid to the resulting mixture, and adjusts the pH value to 4-7 to obtain a wood adhesive based on microcrystalline cellulose to capture carbon dioxide. Alternatively, the MCC@CO2 slurry and chitosan are mixed and heated to dissolve. An acid is added to the resulting mixture to adjust the pH to 4-7, thus obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide.

[0030] In one embodiment, the mass ratio of microcrystalline cellulose to chitosan is 1~2:2~4, specifically 2:4 in this embodiment; the phenolic reinforcing agent includes one or more of hydroquinone (HQ), phenol (PN), and phloroglucinol (PG), specifically hydroquinone in this embodiment; the mass ratio of chitosan to phenolic reinforcing agent is 1~6:0.2~1, specifically 1:0.2 in this embodiment; the heating and dissolving temperature is 35~65℃, specifically 45℃ in this embodiment; the heating and dissolving is carried out under continuous stirring.

[0031] Heating and dissolving allows chitosan and phenolic substances to fully dissolve and disperse, and to initially interact with activated cellulose molecules. Stirring continues until the solid substances are completely dissolved, forming a homogeneous, viscous mixture.

[0032] In one embodiment, the acid is glacial acetic acid; the mass ratio of chitosan to acid volume is (1~4) g:(1~4) mL, and in a specific embodiment it is 4 g:4 mL; the acid is added while stirring; the pH value is adjusted to 4~7, and in a specific embodiment it is 5.

[0033] Upon addition of acetic acid, the reactants typically turn pink (related to the formation of phenolic quinone structures). This color change serves as a visual indicator of the reaction's progress.

[0034] After adjusting the pH value, the process further includes: cooling the material before discharge; the cooling is cooling to room temperature.

[0035] The wood adhesive based on microcrystalline cellulose for capturing carbon dioxide prepared in this invention is a homogeneous, viscous liquid that can be directly used for coating or for packaging and storage.

[0036] The present invention also provides a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide prepared by the preparation method described in the above technical solution.

[0037] The present invention also provides the application of the microcrystalline cellulose-based carbon dioxide capture wood adhesive described above in the preparation of wood panels.

[0038] The present invention also provides a method for preparing plywood, comprising the following steps: After applying adhesive to the veneer, multiple layers of veneers are combined and hot-pressed to obtain plywood. The adhesive is the wood adhesive based on microcrystalline cellulose for capturing carbon dioxide described in the above technical solution.

[0039] In one embodiment, the veneer is poplar veneer; the adhesive coating amount is 200~300g / m². 2 In the specific embodiment, it is 240g / m 2 The multilayer consists of 3 to 5 layers, with 3 layers in a specific embodiment; the hot pressing pressure is 0.8 to 2 MPa, with 1 MPa in a specific embodiment, the temperature is 140 to 180°C, with 160°C in a specific embodiment, and the time is 5 to 8 minutes, with 6 minutes in a specific embodiment; the thickness of the single board is 1.5 to 2.5 mm, with 2 mm in a specific embodiment.

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0041] Chemicals and Materials Microcrystalline cellulose (MCC, 90 μm), chitosan, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), phenol (PN), hydroquinone (HQ), phloroglucinol (PG), dimethyl sulfoxide (DMSO), carbon dioxide, and acetic acid were used. The poplar veneer used in the preparation of the plywood was purchased from Zhiwei Veneer Factory in Langfang City, Hebei Province, China. Distilled water (DW) was prepared in the laboratory.

[0042] Example 1 Basic adhesive: MCC@CO2-CS (phenol-free reinforcement) Objective: To prepare a basic biomass adhesive without phenolic reinforcing agents and evaluate its basic properties.

[0043] Test method: 1. Activation: In a 100mL round-bottom flask, add 2.0g microcrystalline cellulose (MCC, 90μm), 800μL DBU, 4mL DMSO and 38mL deionized water. In an oil bath at 45℃, continuously introduce CO2 gas and stir at 600r / min for 12h to obtain MCC@CO2 slurry. 2. Mixing: Transfer the above slurry to a 500mL beaker, add 4.0g of chitosan (CS), and stir at 45℃ until completely dissolved to form a homogeneous mixture; 3. pH adjustment and discharge: Add 4 mL of glacial acetic acid to the mixture while stirring until the pH value of the system is about 5. Cool to room temperature to obtain MCC@CO2-CS adhesive.

[0044] 4. Panel Preparation and Testing: Take poplar veneer and apply the above-mentioned adhesive (approximately 240g / m²). 2 Three-layer plywood was prepared by hot pressing at 1 MPa pressure and 160℃ for 6 minutes.

[0045] The specimens were cut according to GB / T 17657-2022, and their dry shear strength and wet shear strength after treatment under different conditions were tested.

[0046] Experimental results: Dry shear strength: 1.63 MPa (23±2℃, untreated); Wet shear strength: Soaking in cold water (23±2℃) for 24 hours: 1.10 MPa; Soaking in hot water (63±2℃) for 3 hours: 0.81MPa; Performance positioning: The wet strength has met the basic requirements of GB / T 9846-2015 for Class II boards (≥0.7MPa), proving the effectiveness of the basic formula.

[0047] Example 2 High-performance reinforced adhesive: MCC@CO2-CS / HQ Objective: To significantly improve the adhesive strength and water resistance of adhesives by adding hydroquinone (HQ) as a phenolic reinforcing agent.

[0048] Test method: 1. Activation: Same as step 1 in Example 1, prepare MCC@CO2 slurry.

[0049] 2. Mixing and reinforcement: After transferring the slurry, add 4.0g of chitosan and hydroquinone (HQ) at a mass ratio of 1:0.2. Stir at 45°C until the solids are completely dissolved and the mixture becomes a homogeneous viscous consistency.

[0050] 3. pH adjustment and discharge: Add 4 mL of glacial acetic acid to adjust the pH value to 5. Observe that the mixture turns pink. Cool to room temperature to obtain MCC@CO2-CS / HQ adhesive.

[0051] 4. Plate preparation and testing: Same as step 4 in Example 1. Additionally, test the strength after boiling water treatment.

[0052] Experimental results: Dry shear strength: 3.2 MPa; Wet shear strength: Soaking in cold water (23±2℃) for 24 hours: 1.57MPa; Soaking in hot water (63±2℃) for 3 hours: 1.42MPa; Soaking in boiling water (93±2℃) for 3 hours: 1.20 MPa; Wood damage rate (after boiling water treatment): approximately 50%; Residual rate: 80.3%.

[0053] Performance positioning: It has the best overall performance, especially outstanding wet strength, which far exceeds the Class II board standard, and has a color change indicator.

[0054] Example 3 Comparative adhesives: MCC@CO2-CS / PN and MCC@CO2-CS / PG Objective: To explore the effects of different phenolic compounds (phenol PN, phloroglucinol PG) on adhesive properties and compare them with hydroquinone (HQ).

[0055] Test method: Referring to the steps of Example 2, except that in step 2, hydroquinone (HQ) is replaced by the following mass: Group A: Phenol (PN) Group B: Phloroglucinol (PG) Two adhesives, MCC@CO2-CS / PN and MCC@CO2-CS / PG, were prepared and then subjected to the same board fabrication and strength tests.

[0056] Test results (based on) Figure 6 (Data summary) The residual rates of MCC@CO2-CS / PN, MCC@CO2-CS / PG, and MCC@CO2-CS / HQ (control) were 77.2%, 78.1%, and 80.3%, respectively. Regarding the wet shear strength trend, water treatment significantly improved the performance of MCC@CO2-CS / PN and MCC@CO2-CS / PG, while MCC@CO2-CS / HQ exhibited the highest wet strength and the best overall performance.

[0057] Feature Analysis: Phenol has a lower cost and improved performance. Phloroglucinol contains three phenolic hydroxyl groups, potentially providing more cross-linking sites. Hydroquinone is easily oxidized to quinone, providing strong cross-linking and resulting in the most significant performance enhancement.

[0058] Example 4 The oil bath temperature is in the range of 20~50℃ (e.g., 20℃, 30℃, 40℃, 45℃, 50℃). Operating procedures: Same as Example 2, except the oil bath temperature is adjusted.

[0059] The reaction time can be adjusted appropriately (the lower the temperature, the longer the time).

[0060] result: The optimal reaction temperature is 45℃, which yields the highest CO2 capture efficiency (approximately 30%).

[0061] The reaction is slow at 20~40℃ and the reaction time needs to be extended, but effective cross-linking can still be formed.

[0062] The reaction rate is slightly faster at 50℃, but solvent evaporation or side reactions may occur.

[0063] Comparative Example 1 The oil bath temperature should be below 20℃ (e.g., 10℃, 15℃). Operating procedures: Add MCC, DMSO, DBU, and H2O to the reaction flask and place it in a low-temperature thermostat.

[0064] Introduce CO2 and maintain the reaction at 10°C or 15°C for 24 hours.

[0065] The subsequent steps are the same as in Example 2 (adding chitosan, phenols, and adjusting pH).

[0066] result: The reaction rate is slow, and the degree of cellulose activation is low.

[0067] CO2 has increased solubility in solution, but its reactivity decreases.

[0068] The adhesive has a low crosslinking density and poor mechanical properties after curing.

[0069] Comparative Example 2 Oil bath temperature is above 50℃ (e.g., 60℃, 70℃, 80℃). Operating procedures: The reaction flask was placed in a high-temperature oil bath, and the temperature was strictly controlled.

[0070] Because the reaction is accelerated, the reaction time can be shortened (e.g., 8 hours at 60℃ and 4 hours at 80℃).

[0071] Attention should be paid to the volatilization of DMSO and the loss of moisture in the system.

[0072] result: High temperatures can cause DBU to decompose or react irreversibly with CO2.

[0073] Cellulose undergoes thermal degradation, affecting subsequent cross-linking.

[0074] After the adhesive has cured, its brittleness increases and its water resistance decreases.

[0075] Performance testing (1) Test method 1. Chemical structure analysis Fourier transform infrared spectroscopy (FT-IR; Tenson 27) was used to test the mixture of dried samples and dried potassium bromide tablets to verify the transformation of key functional groups (such as aldehyde groups) in the adhesive. X-ray photoelectron spectroscopy (XPS; Thermo Scientific K-Alpha) was used to determine the composition of the adhesive, with voltages of 100 eV and 30 eV for full-spectrum and narrow-spectrum scans, respectively, and step sizes of 1.0 eV and 0.1 eV, respectively. After argon ion etching for 15 seconds, all bond energies were calibrated to the C1s bond energy of surface-contaminated carbon (284.8 eV), and the data were analyzed using Avantage software.

[0076] 2. Thermal performance analysis.

[0077] Differential scanning calorimetry (DSC; Netzsch DSC 200 F3) can determine the glass transition temperature (Tg), thus effectively determining the temperature parameters for hot pressing of adhesives. A known mass of sample was placed in an aluminum crucible, and the crucible containing the sample, along with an empty crucible, was placed in the thermostat chamber of the DSC instrument. Key experimental parameters were set as follows: initial temperature 50℃, final temperature 200℃, and heating rate 15K / min. Thermogravimetric analysis (TGA; Netzsch STA 2500) was used to detect the thermal stability and decomposition of dried MCC@CO2-CS and MCC-CS samples. Approximately 7 mg of sample in a ceramic crucible was sealed in the instrument's furnace. The program was set to heat from 50℃ to 800℃ at a rate of 10℃ / min. The raw data were processed using the first derivative before analysis.

[0078] 3. Bond strength test The experimental steps and parameters are as follows: Two veneers and one reverse-grain core board were taken. Approximately 240 g / m² of adhesive was applied to each veneer. After several minutes of pressure overlap, the layers were hot-pressed at 1 MPa and 160°C for 6 minutes. The three-layer plywood was then sawn into test samples (100 mm × 25 mm), with the bonding area maintained at 25 mm × 25 mm. Bond strength was determined according to GB / T 17657-2022 standard using a computer-controlled electromechanical universal testing machine (HDW-100H, Jinan, China). The strength of the plywood with the three adhesives was measured: the strength after immersion in water for 3 hours (63°C) and 3 hours in boiling water (93°C), and the dry strength after immersion at room temperature (23°C) for 24 hours. Each sample underwent a tensile fracture test within 30 seconds at a rate of 5 mm / min.

[0079] 4. Residue rate and hygroscopicity test The cured adhesive sample was dried in an oven at 110±3℃ to constant weight (m1). Then, the sample was added to a conical flask containing water and placed in an oven at 60℃ for 6 hours. After removing the sample, it was dried again in an oven at 110±3℃. The process was repeated. The ratio of m2 to m1 represents the residual rate of the cured adhesive.

[0080] The constant-weight adhesive sample was ground into tiny particles to ensure sufficient contact with moisture, weighed (m1), and placed in a saturated potassium chloride solution with a relative humidity of approximately 80%. The entire container was then placed in a 60°C oven and weighed every 1.5 hours until a constant weight (m2) was achieved. The moisture absorption value was calculated using the formula (m2-m1) / m1 × 100%.

[0081] 5. Other characteristics To observe the penetration of adhesives into wood at a microscopic level, glue lines in plywood were examined using an electron biological microscope, and sections were prepared along the thickness of the plywood using a microtome. Since the adhesive itself is chromogenic, the staining step was omitted. The sections were fixed onto glass slides with glycerin, and the glue line images were then observed under different objective magnifications.

[0082] (2) Figure 1Figure A shows a schematic diagram of microcrystalline cellulose capturing carbon dioxide; Figure B shows a schematic diagram of the preparation process and molecular structure of MCC@CO2-CS / HQ adhesive; Figure C shows a demonstration diagram of wood board sample preparation and adhesive performance evaluation; Figure D shows a comparative analysis of the shear strength of the developed MCC@CO2-CS / HQ adhesive with previously reported adhesives (CT@BNNSs / CS / SM adhesive, TA-PDMI-4%BA adhesive, UF-lignin adhesive, P-OS-M25 adhesive, starch adhesive, SP / MCN / DPL@VA adhesive, SM / BD / 5% HPFC adhesive, TA-PA6N adhesive, and OS-AC adhesive).

[0083] This invention is based on the carbonation reaction of cellulose and carbon dioxide in the presence of an organic base, in which glucose units on the cellulose chain are activated to produce the MCC@CO2 product. Figure 1 As shown in Figure A, MCC@CO2 forms a rigid linear structure and interacts with the chitosan solution. The carbonate groups on the cellulose molecules cross-link with the ammonium ions on the chitosan molecules, forming a three-dimensional network structure. After hot-press curing, the resulting material exhibits satisfactory mechanical strength.

[0084] To further improve adhesion performance, this invention introduces various phenolic compounds to enhance the bonding properties of plywood and reduce the required hot-pressing temperature. Hydroquinone (HQ) is used as an example: Figure 1 As shown in Figure B, microcrystalline cellulose (MCC) is treated with carbon dioxide and then mixed with a chitosan solution. Under the cross-linking action of hydroquinone, a high-performance biomass-based wood adhesive is formed. The detailed preparation process of MCC@CO2-CS / HQ adhesive from raw materials to final processing is as follows... Figure 2 As shown in the figure, initially, cellulose captures carbon dioxide in a dimethyl sulfoxide (DMSO) / dibutylhydrazine (DBU) system, generating a carboxylic acid structure at the C6 position of the glucose unit. Subsequently, hydroquinone and chitosan were added to the reaction mixture and stirred uniformly at 45°C. Finally, acetic acid was added to adjust the pH to 5. After hot pressing at 160°C and boiling water treatment, the plywood bonded with MCC@CO2-CS / HQ adhesive achieved a dry shear strength of 3.2 MPa and a wet strength of 1.31 MPa. The addition of hydroquinone significantly improved the adhesive properties. It is speculated that during the reaction, hydroquinone is readily oxidized to p-benzoquinone, thereby providing additional bonding sites between the cellulose and chitosan molecular chains. This mechanism was confirmed by subsequent experimental analysis. Figure 1 Table C presents the implementation standard (GB / T17657-2022) for evaluating plywood samples and the corresponding wood failure rate. In addition, the performance of other adhesive formulations was investigated. For example... Figure 1As shown in Figure D, the MCC@CO2-CS / HQ adhesive exhibits excellent wet strength and acceptable dry strength. This invention not only provides a sustainable alternative to traditional petroleum-based adhesives but also contributes to the development of a low-carbon economy by utilizing carbon dioxide in the synthesis of cellulose-based materials, thus opening up new avenues for carbon dioxide utilization.

[0085] (3) Figure 3 Image A shows SEM images of MCC raw materials, MCC capturing carbon dioxide (MCC@CO2), and MCC@CO2-CS / HQ adhesive. Image B shows SEM images of the glue lines and glue pins of a (dry) wood board sample. Image C shows SEM images of the glue lines and glue pins of a (wet) wood board sample.

[0086] After being treated with an optimized solvent system, MCC, a biomass adhesive made from modified cellulose and chitosan, has a dense structure. Figure 3 Image A shows SEM images of MCC from raw material processing to adhesive. After capturing carbon dioxide, the MCC particles exhibit increased activity, and the increase in intermolecular active groups leads to the polymerization of MCC particles to form a sheet-like structure. The MCC@CO2-CS / HQ adhesive sample forms this dense structure after curing.

[0087] like Figure 3 As shown in Figures B and C, the formation process of adhesive lines under different conditions can be clearly observed using an optical microscope. Once the adhesive is pressed into the wood surface to form a glue nail, it can penetrate into the wood tissue. Therefore, the adhesive and the wood have a good mechanical interlocking effect.

[0088] (4) Figure 4 In the diagram, A represents the FT-IR curves of MCC and MCC@CO2, B represents the FT-IR curves of MCC-CS / HQ and MCC@CO2-CS / HQ adhesives, C represents the XPS spectra of MCC-CS / HQ and MCC@CO2-CS / HQ adhesives, DF represents the high-resolution spectra of C1s, N1s, and O1s in MCC@CO2-CS / HQ adhesive, and GI represents the high-resolution spectra of C1s, N1s, and O1s in MCC-CS / HQ adhesive.

[0089] To further explore the synthesis mechanism of adhesives, this invention characterized the materials using Fourier transform infrared spectroscopy (FT-IR) and XPS testing. Figure 4 As shown in A, approximately 3350cm -1 The broad peak at 2900 cm⁻¹ corresponds to the -OH stretching vibration of cellulose. -1 The stretching vibrations at these locations are the CH stretching vibrations of the methyl and methylene groups on the cellulose backbone. (1640, 1430, and 1055 cm⁻¹)-1 These correspond to the OH bending vibration, the methylene bending vibration, and the CH2-O-CH2 stretching vibration, respectively. The FT-IR spectrum of MCC@CO2 differs slightly from that of MCC, at 1610 cm⁻¹. -1 The peak at this location corresponds to the C=O stretching vibration peak on the cellulose molecular chain, proving that carboxylic acid (-COOH) or carbonate groups were successfully introduced into the cellulose chain after the CO2 reaction. Figure 4 As shown in Figure B, the MCC@CO2-CS / HQ adhesive at 1640cm -1 The peak at the point of origin is obvious, while MCC-CS / HQ shows no characteristic peak, indicating that there is a good cross-linking effect between MCC@CO2 and chitosan.

[0090] Comparative measurements and high-resolution spectroscopic analysis of MCC-CS / HQ and MCC@CO2-CS / HQ showed that the introduction of carbon dioxide led to an increase in active sites on the cellulose molecular chain, such as... Figure 4 As shown in Figure D, the peaks at 284.53, 285.36, 286.1, 287.52, and 288.2 eV are attributed to CC, CN, CO, OCO, and O=CO bonds. This indicates that a bridging covalent crosslinking mechanism exists between p-benzoquinone and carboxylic acids in MCC@CO2.

[0091] In the high-resolution spectrum of N1s, compared with the sample that did not capture CO2 ( Figure 4 Compared to H), the C=N peaks at 398.75 eV and 401.03 eV are enhanced ( Figure 4 The high-resolution O1s spectra of MCC-CS / HQ and MCC@CO2-CS / HQ (E) indicate a successful cross-linking reaction between CS and MCC. Figure 4 Compared to F and I), the cured sample contained a small number of C=O bonds, which resulted in more intermolecular bonding sites during the curing process, thus forming a network cross-linked structure. This confirms that the introduction of carbon dioxide gives cellulose more active sites, thereby giving the adhesive better bonding properties after curing.

[0092] (5) Figure 5 In the diagram, A is the XPS spectrum of MCC-CS and MCC@CO2, B is the high-resolution spectrum of C1s in MCC, C is the high-resolution spectrum of C1s in MCC@CO2, and D is a comparison of different bond energies between MCC and MCC@CO2.

[0093] Considering the efficiency of cellulose in capturing carbon dioxide, XPS was used to further investigate changes in the functional groups within cellulose. For example... Figure 5As shown in Figure A, the carbon content of the modified cellulose decreased from 69.5% to 65.39%, while the oxygen content increased from 30.5% to 34.61%. In the C1s spectrum of MCC, CC groups accounted for 24.67%, CO groups accounted for 56.44%, and OCO groups accounted for 18.89%. Figure 5 (B, D). In the C1s spectrum of MCC@CO2, CC groups account for 21.38%, CO groups account for 60.44%, OCO groups account for 10.67%, and O=CO groups account for 7.51%. Figure 5 (C, D) indicates that carbon dioxide was successfully introduced during the cellulose modification process. XPS analysis ( Figure 5 Further investigation (A, C, and D) confirmed the presence of new O=CO bonds (7.51%) in the modified material, along with a significant increase in oxygen content. This directly stems from the chemical reaction between CO2 and cellulose under DBU action. Preliminary calculations show a carbon dioxide capture efficiency of 30%, meaning that approximately 73 kg of pure carbon dioxide can be consumed using 1 ton of cellulose.

[0094] (6) Figure 6 In the figures, A, B, and C represent the DSC curves of adhesives prepared from MCC-CS, MCC@CO2-CS, phenol, hydroquinone, and phloroglucinol, respectively. D compares the curing temperatures of the three adhesive systems. E compares the interfacial bonding distances measured by X-ray scattering or supplementary structural analysis. F is a schematic diagram illustrating the intermolecular spacing regulation caused by different quinone comonomers. G and H are the TG and DTG curves of MCC@CO2-CS / PN, MCC@CO2-CS / HQ, and MCC@CO2-CS / PG adhesives, highlighting thermal stability and decomposition kinetics. I represents the proposed binding mechanism of the MCC@CO2-CS / HQ adhesive, emphasizing quinone-mediated covalent crosslinking and hydrogen bonding enhancement.

[0095] Hot pressing is a key industrial processing step in wood adhesives. Given the significant impact of the thermal behavior of microcrystalline cellulose (MCC) and chitosan (CS) on curing kinetics, bond strength, and water resistance, differential scanning calorimetry (DSC) was used to characterize the curing curves of three hybrid adhesive systems: MCC-CS / PN and MCC@CO2-CS / PN. Figure 6 (A); MCC-CS / HQ and MCC@CO2-CS / HQ ( Figure 6 (Middle B); and MCC-CS / PG and MCC@CO2-CS / PG ( Figure 6(C). All formulations exhibited significant exothermic curing peaks, with MCC@CO2-CS / PN showing an onset temperature of 130 ℃, MCC@CO2-CS / HQ at 120 ℃, and MCC@CO2-CS / PG at 160 ℃. For reference, the DSC curves for adhesives containing 8 wt% pure chitosan (…) are shown. Figure 7 The data showed a single exothermic peak centered at ~120 °C, confirming that the chitosan self-curing reaction was initiated near this temperature. Compared to the non-carboxymethylated corresponding systems (MCC-CS / PN, MCC-CS / HQ, MCC-CS / PG), the CO2-modified adhesives consistently exhibited lower curing initiation temperatures, with the HQ-containing system showing particularly significant reductions, thus achieving energy-efficient processing. Figure 6 (D). To ensure complete cross-linking of all formulations, the hot-pressing temperature for subsequent adhesion tests was uniformly set at 160 ℃. We hypothesize that the phenolic co-reactants affect the reaction kinetics by adjusting the intermolecular distance between MCC@CO2 and the CS chains. Distance analysis assisted by molecular docking ( Figure 6 China E and Figure 6 The results from the study confirmed that MCC@CO2-CS / HQ had the largest average interchain spacing (3.8 Å), followed by MCC@CO2-CS / PG (3.2 Å), and MCC@CO2-CS / PN had the smallest (2.9 Å). This trend was negatively correlated with the measured curing temperature and was consistent with the mechanism that enhanced conformational migration ability promotes nucleophilic reactions.

[0096] Thermogravimetric analysis (TGA) was used to evaluate the thermal stability and decomposition kinetics of the MCC@CO2-CS / HQ adhesive. Figure 6 China G (TG) and Figure 6 As shown in the H (DTG) curves, the system exhibits a two-stage decomposition characteristic: the first stage, characterized by significant weight loss, begins at ~90℃ and peaks at 360℃, corresponding to a mass loss of 42.98% and a maximum decomposition rate of -3.26% / min. This is attributed to the breaking of unstable hydrogen bonds and the cleavage of some covalent cross-links (such as Schiff bases). Compared to similar systems containing phenol or resorcinol, this HQ-containing system demonstrates superior thermal stability, specifically manifested in a higher rapid degradation initiation temperature and smaller mass loss at lower temperatures. A distinct inflection point near 370℃ marks the initiation of the second-stage decomposition (370-500℃), a process associated with the gradual degradation of a quinone-mediated thermally stable network—potentially originating from intramolecular and intermolecular covalent bonds formed between p-benzoquinone (generated from the in-situ oxidation of hydroquinone) and chitosan amino groups. As a control, the TGA and DTG curves for an adhesive containing 8 wt% pure chitosan are compared. Figure 8 and Figure 9The spectrum shows a single dominant decomposition event, with a peak at ~360℃, greater mass loss (57.65%), and a higher peak decomposition rate (-4.46% / min), confirming its poor thermal stability. Mechanisms based on these thermal analysis spectra ( Figure 6 (I) indicates that hydroquinone is easily oxidized to p-benzoquinone during adhesive preparation, thereby enriching electrophilic C=O groups and promoting the efficient formation of Schiff bases with chitosan amino groups. This mechanism, combined with the increased crosslinking density brought about by the bifunctional characteristics of quinone, constitutes the basis for the superior cohesive strength and thermal properties of MCC@CO2-CS / HQ compared to systems containing phenol or resorcinol.

[0097] (7) Figure 10 Figures A and B show the mechanical properties of MCC-CS adhesive and MCC@CO2-CS adhesive with phenol, hydroquinone, and phloroglucinol under different conditions. Figure C shows the wood failure rate of three-layer board samples prepared with MCC-CS / HQ adhesive and MCC@CO2-CS / HQ adhesive after being treated with cold water for 24 hours, hot water for 3 hours, and boiling water for 3 hours, respectively. Figure D shows the residual rate and moisture absorption value of MCC-CS, MCC@CO2-CS / PN, MCC@CO2-CS / HQ, and MCC@CO2-CS / PG. Figure E shows the performance comparison of samples after high-temperature curing after soaking in water for 30 days and soaking in DMSO for 30 days.

[0098] Based on the excellent bonding performance and water resistance of MCC@CO2-CS adhesive, this invention prepared three different types of wood panels to further evaluate the application performance of this adhesive. According to the Chinese National Standard GB / T 17657-2022, standard three-layer plywood samples were prepared using fast-growing poplar veneer to evaluate the wet shear strength of the MCC@CO2-CS adhesive. Figure 11 As shown, the adhesive prepared using 8wt% CS exhibited a dry strength of 1.63 MPa and a wet shear strength of 1.1 MPa after treatment with cold water at 23±2℃ for 24 h; however, after treatment with hot water at 63±2℃ for 3 h, the wet shear strength only decreased to 0.81 MPa. Under different conditions, water treatment significantly improved the performance of the adhesive prepared by MCC@CO2-CS, while the performance of the MCC@CO2-CS / HQ adhesive was worse (shear strength data can be found in...). Figure 10 (A, B). After being treated with hot water at 63±2℃ for 3 hours, the wet shear strength of the plywood prepared with MCC@CO2-CS / HQ adhesive was only 0.76 MPa, while MCC@CO2-CS / PN and MCC@CO2-CS / PG showed good performance improvement after treatment under different conditions. The wood damage effect of MCC@CO2-CS / HQ plywood was demonstrated. Figure 10The adhesive, after capturing carbon dioxide (C), exhibits better wood-damaging effects: the wood damage rate is 90% after 24 hours of cold water (23±2℃), 70% after 3 hours of hot water (63±2℃), and approximately 50% after 3 hours of boiling water (93±2℃). This is likely due to the introduction of carbon dioxide, which increases the active sites on cellulose molecules and enhances the crosslinking density in the cured adhesive. This allows the adhesive to better penetrate the wood surface during curing, forming glue nails within the wood, thereby improving the bond strength of the final plywood sample. This also confirms that the introduction of carbon dioxide improves bond strength. Under appropriate heating conditions, hydroquinone is more easily oxidized to p-benzoquinone during adhesive preparation, resulting in a higher C=O bond content in the colloid itself. This is partly why the MCC@CO2-CS / HQ adhesive outperforms phenolic and resorcinol adhesives. The wet shear strength of the plywood in this invention exceeds the requirements of GB / T 9846-2015 for Class II boards (≥0.7MPa).

[0099] Undoubtedly, adhesive strength is an important indicator for evaluating adhesive performance, but it is not an absolute standard. In addition to immersion testing, this invention also uses the shear strength of the re-dried lap joint to assess moisture absorption and residue, and further verifies its moisture resistance (e.g., through moisture absorption testing). Figure 10 (As shown in D). The residual rates of the modified adhesives increased to 73.2% (MCC@CO2-CS / PN, residual rate 77.2%), 68.3% (MCC@CO2-CS / HQ, residual rate 80.3%), and 65.8% (MCC@CO2-CS / PG, residual rate 78.1%), respectively, while the residual rate of the pure MCC-CS adhesive was 63.9%. The results indicate that the adhesive prepared by covalent crosslinking via amide reaction has higher moisture resistance than the precursor structure of MCC molecular chains linked by hydrogen bonds. Notably, a small amount of cured sample was placed in water and DMSO and observed after 30 days ( Figure 10 The study found that, due to further cross-linking during the curing process, the sample exhibited good stability to both water and DMSO, and excellent solvent stability.

[0100] In summary, current cellulose modification still faces challenges such as dissolution difficulties and solvent limitations. Therefore, this invention optimizes the DMSO / DBU solvent system, using water as the main solvent. By introducing carbon dioxide to form carboxylic acid structures on the cellulose molecular chain, cellulose is simply modified. This modified cellulose is then mixed with a chitosan solution to prepare a fully biomass wood adhesive with excellent adhesion and water resistance. This method is simple to operate, involves a one-step preparation, and eliminates the need for subsequent cellulose purification. MCC@CO2, as a rigid linear chain, shuttles with the softly acidified chitosan and sequentially fixes the chitosan between chain layers through specific anchoring points. During the curing process, intermolecular hydrogen bonds become saturated, preventing water molecule intrusion. The resulting cross-linked network adhesive exhibits excellent shear strength and water resistance. The addition of hydroquinone lowered the curing temperature of the adhesive and further improved its bonding properties, resulting in a high-performance MCC@CO2-CS / HQ adhesive with a dry strength of 3.2 MPa, a wet strength of 1.57 MPa after 24 hours in cold water (23°C), and wet strengths of 1.42 MPa and 1.20 MPa after immersion in hot water (63°C) and boiling water for 3 hours, respectively. The carbon dioxide-activated cellulose-chitosan crosslinking network exhibited excellent thermal stability and water resistance. Carbon dioxide was used as a linker in the crosslinking network to improve the utilization efficiency of cellulose. Simultaneously, the introduction of carbon dioxide enhanced the overall calorific value of the product. Using long-life wood products can delay the release of carbon dioxide into the atmosphere, providing more time to address climate change. This invention not only provides a new method for biomass adhesives but also promotes the development of a low-carbon economy.

[0101] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a wood adhesive based on microcrystalline cellulose for capturing carbon dioxide, characterized in that, Includes the following steps: Microcrystalline cellulose, 1,8-diazabicyclo[5.4.0]undec-7-ene, dimethyl sulfoxide and water were mixed first, and carbon dioxide gas was introduced into the resulting reaction solution under oil bath conditions to carry out the activation reaction, so as to obtain MCC@CO2 slurry; The MCC@CO2 slurry, chitosan and phenolic reinforcing agent are heated and dissolved. Acid is added to the resulting mixture to adjust the pH value to 4-7, thereby obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide. Alternatively, the MCC@CO2 slurry and chitosan are mixed and heated to dissolve. An acid is added to the resulting mixture to adjust the pH to 4-7, thus obtaining a wood adhesive based on microcrystalline cellulose to capture carbon dioxide.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the microcrystalline cellulose to the volume ratio of 1,8-diazabicyclo[5.4.0]undec-7-ene is (1~2) g:(400~800) μL; the mass ratio of the microcrystalline cellulose to the volume ratio of dimethyl sulfoxide is (1~2) g:(2~4) mL.

3. The preparation method according to claim 1, characterized in that, The temperature of the oil bath is 35~65℃; the activation reaction time is 8~24h.

4. The preparation method according to claim 1, characterized in that, The phenolic enhancer includes one or more of hydroquinone, phenol, and phloroglucinol.

5. The preparation method according to claim 1, characterized in that, The mass ratio of microcrystalline cellulose to chitosan is 1~2:2~4.

6. The preparation method according to claim 1 or 4, characterized in that, The mass ratio of chitosan to phenolic reinforcing agent is 1~6:0.2~1.

7. The preparation method according to claim 1, characterized in that, The acid is glacial acetic acid.

8. A wood adhesive based on microcrystalline cellulose for capturing carbon dioxide, prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the microcrystalline cellulose-based carbon dioxide capture wood adhesive of claim 8 in the preparation of wood panels.

10. A method for preparing plywood, characterized in that, Includes the following steps: After applying adhesive to the veneer, multiple layers of veneers are combined and hot-pressed to obtain plywood. The adhesive is the wood adhesive based on microcrystalline cellulose for capturing carbon dioxide as described in claim 8.

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