Process for modifying wood by using high-stability composite nano material

Abstract

The invention relates to a process for modifying wood through a high-stability composite nano material, and belongs to the technical field of wood modification. The technology for modifying the wood through the high-stability composite nanometer material comprises the following steps that the wood is cleaned and dried, and pretreated wood is obtained; the preparation method comprises the following steps: dissolving a functional monomer, hydroxyl acrylamide and allyl glycidyl ether in absolute ethyl alcohol, adding a titanate coupling agent and an initiator, and stirring and mixing to obtain modified liquid; and the pretreated wood is soaked in the modified liquid for dipping treatment, the wood is taken out, deionized water is sprayed to the surface of the wood, aging and heating heat preservation treatment are conducted, vacuum drying is conducted till the weight is constant, and the wood is obtained. According to the method, a nano titanium dioxide material can be effectively combined with a wood matrix, and meanwhile, the hydrophobicity, the antibacterial property and the compressive strength of the wood are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the technical field of wood modification, and relates to a process for modifying wood with highly stable composite nanomaterials. Background Technology

[0002] Wood, as a renewable and environmentally friendly natural material, has a wide range of applications in construction, furniture, decoration, and packaging. However, natural wood itself has many performance defects that severely limit its scope of use and lifespan. On the one hand, wood is a porous and hydrophilic material. Its rich cellulose, hemicellulose, and lignin structures contain a large number of hydroxyl groups, making it extremely susceptible to moisture absorption, which can lead to deformation, cracking, and other problems, thus shortening its lifespan. On the other hand, a humid environment provides ideal conditions for the survival of microorganisms (such as fungi and bacteria), making wood vulnerable to decay, mold, and insect infestation. This not only reduces the mechanical properties of the wood but may also pose a potential threat to human health.

[0003] To address these issues, traditional wood modification techniques include physical treatments (such as high-temperature heat treatment and microwave treatment), chemical treatments (such as preservative impregnation and resin impregnation), and biological treatments (such as enzyme treatment). While physical treatments can improve the dimensional stability of wood to some extent, their effect on improving mechanical properties and antibacterial properties is limited.

[0004] In recent years, nanomaterial modification technology has provided new directions for wood modification due to its unique size effect and excellent performance. Nano-titanium dioxide has good photocatalytic antibacterial and reinforcing effects, while polymer materials can impart hydrophobicity and mechanical reinforcement to wood. However, current wood modification processes based on nanomaterials still face some technical bottlenecks, such as poor dispersion of nanoparticles in wood, weak interfacial bonding with the wood matrix, and difficulty in achieving efficient synergistic improvement of multiple properties during the modification process. Summary of the Invention

[0005] The purpose of this invention is to provide a process for modifying wood with highly stable composite nanomaterials. This invention can effectively combine nano-titanium dioxide materials with the wood matrix, while significantly improving the hydrophobicity, antibacterial properties and compressive strength of the wood.

[0006] The objective of this invention can be achieved through the following technical solutions: A process for modifying wood with highly stable composite nanomaterials includes the following steps: Step 1: Clean and dry the wood to obtain pretreated wood; Step 2: Dissolve the functional monomer, hydroxyacrylamide and allyl glycidyl ether in anhydrous ethanol, add titanate coupling agent and initiator and stir to mix to obtain modified liquid; Step 3: Immerse the pretreated wood in the modified liquid for impregnation, remove the wood and spray deionized water on its surface, age it, heat and keep it warm, and vacuum dry it to constant weight to obtain the final product.

[0007] As a preferred technical solution of the present invention, in step one, the cleaning is to wash the wood surface with deionized water, and the drying is to dry at 85°C for 4-6 hours and at 100°C to constant weight. The cleaning removes surface microorganisms and impurities, and the drying treatment directly reduces the moisture content of the wood and reduces the moisture in the pores, laying the foundation for subsequent hydrophobic modification.

[0008] As a preferred technical solution of the present invention, in step two, the stirring and mixing is carried out at a speed of 400-600 rpm for 15-20 minutes.

[0009] As a preferred embodiment of the present invention, in step two, the mass ratio of the functional monomer, hydroxyacrylamide, allyl glycidyl ether, titanate coupling agent, initiator and anhydrous ethanol is 6-8:2.0-2.5:1.4-1.8:1.2-1.5:0.20-0.22:30-40, and the initiator is initiator AIBN.

[0010] As a preferred technical solution of the present invention, in step three, the modified liquid penetrates into the pores of the wood, and the hydrophobic polymer formed by polymerization covers the surface and internal channels of the wood, hindering water penetration. The titanium dioxide nanoparticles generated by the hydrolysis of the titanate coupling agent can form a rough surface, improving compressive strength and toughness. The titanium dioxide nanoparticles combined with the hydrophobic polymer further enhance hydrophobicity through the lotus leaf effect. The titanium dioxide nanomaterials can generate photocatalytic free radicals under light irradiation, destroying bacterial cell membranes and achieving antibacterial effects.

[0011] In step three, the volume ratio of the pretreated wood to the modified liquid is 1:6.

[0012] As a preferred embodiment of the present invention, in step three, the impregnation treatment is to impregnate under vacuum at -0.08MPa for 40-60 minutes, followed by impregnation under pressure at 1MPa for 2.0-3.0 hours.

[0013] As a preferred embodiment of the present invention, in step three, the amount of deionized water sprayed is 0.4-0.5 times the weight gain of the pretreated wood after impregnation.

[0014] As a preferred embodiment of the present invention, in step three, the aging is carried out at room temperature for 24-30 hours, the heating and heat preservation treatment is carried out at 80°C for 6-8 hours and then at 110-120°C for 1.0-1.5 hours, and the vacuum drying is carried out to constant weight.

[0015] As a preferred embodiment of the present invention, in step two, the method for preparing the functional monomer includes the following steps: Under an inert atmosphere, acrolein, acetic acid, and anhydrous ethanol are mixed, o-chloroaniline is added, and the mixture is heated and stirred, then rotary evaporated and freeze-dried to obtain the final product.

[0016] As a preferred embodiment of the present invention, in the preparation of the functional monomer, the inert atmosphere is either nitrogen or argon, the heating and stirring is carried out at 60-65°C and 200-400 rpm for 4-6 hours, and the mass ratio of acrolein, o-chloroaniline, acetic acid and anhydrous ethanol is 2.8-4.0:2.0-2.5:0.06-0.08:20-25.

[0017] The beneficial effects of this invention are: This invention achieves simultaneous improvement of the hydrophobicity, antibacterial properties, and compressive strength of wood by synergistic modification of functional monomers, specific chemical reagents, and wood, and by using titanate coupling agents to hydrolyze and generate nano-titanium dioxide. This overcomes the limitations of traditional modification technologies in terms of their singularity and is both environmentally friendly and highly efficient. Attached Figure Description

[0018] Figure 1 Infrared image of a functional unit; Figure 2 Infrared image of wood modified with highly stable composite nanomaterials; Figure 3 This is an experimental diagram of the contact angle of the sample in Example 3; Figure 4 The experimental diagram shows the contact angle of the sample in Comparative Example 2; Figure 5 The experimental diagram shows the contact angle of sample 3 in Comparative Example 3; Figure 6 The experimental diagram shows the contact angle of sample 6 in Comparative Example 6; Figure 7 This is a plate image showing the co-culture of the control group and Escherichia coli culture. Figure 8 This is a plate image of the sample material from Example 3 after co-culturing with Escherichia coli culture; Figure 9 This is a plate image showing the co-culture of the sample material and Escherichia coli culture in Comparative Example 2. Figure 10 This is a plate image of the sample material from Comparative Example 3 after co-culturing with Escherichia coli culture; Figure 11 This is a plate image showing the co-culture of the sample material of Comparative Example 6 with Escherichia coli culture. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0020] The wood used in this embodiment and the comparative example is 10-year-old fast-growing poplar, and the titanate coupling agent is triisostearate isopropyl titanate.

[0021] Example 1 A process for modifying wood with highly stable composite nanomaterials includes the following steps: Step 1: Clean the wood surface with deionized water, then dry it at 85℃ for 4 hours and at 100℃ to constant weight to obtain pretreated wood; Step 2: Dissolve the functional monomer, N-hydroxyacrylamide, and allyl glycidyl ether in anhydrous ethanol, add titanate coupling agent and initiator AIBN, and stir at 400 rpm for 15 min to obtain the modified liquid; wherein, the mass ratio of functional monomer, N-hydroxyacrylamide, allyl glycidyl ether, titanate coupling agent, initiator AIBN and anhydrous ethanol is 6:2.0:1.4:1.2:0.20:30; Step 3: Immerse the pretreated wood in the modified liquid, then impregnate it under vacuum at -0.08 MPa for 40 min, followed by impregnation under pressure at 1 MPa for 2.0 h. Remove the wood and spray deionized water onto its surface. Aged at room temperature for 24 h, kept at 80℃ for 6 h, and kept at 110℃ for 1.0 h, then vacuum dried to constant weight. The amount of deionized water sprayed is 0.4 times the weight gain of the pretreated wood after impregnation, and the volume ratio of the pretreated wood to the modified liquid is 1:6.

[0022] The preparation method of the functional monomer includes the following steps: Under a nitrogen inert atmosphere, acrolein, acetic acid and anhydrous ethanol were mixed, o-chloroaniline was added and stirred at 60°C and 200 rpm for 4 hours. After removing the solvent by rotary evaporation, the mixture was freeze-dried to obtain the final product. The mass ratio of acrolein, o-chloroaniline, acetic acid and anhydrous ethanol was 2.8:2.0:0.06:20.

[0023] Example 2 A process for modifying wood with highly stable composite nanomaterials includes the following steps: Step 1: Clean the wood surface with deionized water, then dry it at 85℃ for 5 hours and at 100℃ to constant weight to obtain pretreated wood; Step 2: Dissolve the functional monomer, N-hydroxyacrylamide, and allyl glycidyl ether in anhydrous ethanol, add titanate coupling agent and initiator AIBN, and stir at 500 rpm for 18 min to obtain the modified liquid; wherein, the mass ratio of functional monomer, N-hydroxyacrylamide, allyl glycidyl ether, titanate coupling agent, initiator AIBN and anhydrous ethanol is 7:2.2:1.6:1.4:0.21:35; Step 3: Immerse the pretreated wood in the modified liquid, then impregnate it under vacuum at -0.08 MPa for 50 min, followed by impregnation under pressure at 1 MPa for 2.5 h. Remove the wood and spray deionized water onto its surface. Aged at room temperature for 27 h, kept at 80℃ for 7 h, and then kept at 115℃ for 1.2 h. Vacuum dried to constant weight to obtain the final product. The amount of deionized water sprayed is 0.45 times the weight gain of the pretreated wood after impregnation, and the volume ratio of the pretreated wood to the modified liquid is 1:6.

[0024] The preparation method of the functional monomer includes the following steps: Under a nitrogen inert atmosphere, acrolein, acetic acid and anhydrous ethanol were mixed, o-chloroaniline was added and stirred at 62°C and 300 rpm for 5 h. After removing the solvent by rotary evaporation, the mixture was freeze-dried to obtain the final product. The mass ratio of acrolein, o-chloroaniline, acetic acid and anhydrous ethanol was 3.4:2.2:0.07:22.

[0025] Example 3 A process for modifying wood with highly stable composite nanomaterials includes the following steps: Step 1: Clean the wood surface with deionized water, then dry it at 85℃ for 6 hours and at 100℃ to constant weight to obtain pretreated wood. Step 2: Dissolve the functional monomer, N-hydroxyacrylamide, and allyl glycidyl ether in anhydrous ethanol, add titanate coupling agent and initiator AIBN, and stir at 600 rpm for 20 min to obtain the modified liquid; wherein, the mass ratio of functional monomer, N-hydroxyacrylamide, allyl glycidyl ether, titanate coupling agent, initiator AIBN and anhydrous ethanol is 8:2.5:1.8:1.5:0.22:40; Step 3: Immerse the pretreated wood in the modified liquid, then impregnate it under vacuum at -0.08 MPa for 60 min, followed by impregnation under pressure at 1 MPa for 3.0 h. Remove the wood and spray deionized water onto its surface. Aged at room temperature for 30 h, kept at 80℃ for 8 h, and then kept at 120℃ for 1.5 h. Vacuum dried to constant weight to obtain the final product. The amount of deionized water sprayed is 0.5 times the weight gain of the pretreated wood after impregnation, and the volume ratio of the pretreated wood to the modified liquid is 1:6.

[0026] The preparation method of the functional monomer includes the following steps: Under a nitrogen inert atmosphere, acrolein, acetic acid and anhydrous ethanol were mixed, o-chloroaniline was added and stirred at 65°C and 400 rpm for 6 hours. After removing the solvent by rotary evaporation, the mixture was freeze-dried to obtain the final product. The mass ratio of acrolein, o-chloroaniline, acetic acid and anhydrous ethanol was 4.0:2.5:0.08:25.

[0027] like Figure 1 , Figure 2 As shown, Figure 1 The infrared image of the functional unit shows that at 1667 cm⁻¹ -1 The characteristic peak appearing at this point indicates the reaction between the amino group of o-chloroaniline and the aldehyde group of acrolein to form a Schiff base bond. Figure 2 To modify wood with composite nanomaterials, at 651cm -1 The characteristic peaks at this location are mainly attributed to the stretching vibrations of Ti-O, indicating the formation of titanium dioxide. Figure 1 , Figure 2 The peak band ① in the image mainly indicates the signal of the aromatic ring of the o-chloroaniline phase, indicating that the composite nanomaterials modified wood were successfully prepared.

[0028] Comparative Example 1 Compared with Example 3, Comparative Example 1 differs in that N-hydroxyacrylamide is used instead of allyl glycidyl ether, while all other aspects are the same.

[0029] Comparative Example 2 Compared with Example 3, Comparative Example 2 differs in that N-hydroxyacrylamide replaces the functional monomer, while all other aspects are the same.

[0030] Comparative Example 3 Compared with Example 3, Comparative Example 3 differs in that o-chloroaniline is not used, and ethyl methacrylate is used instead of the functional monomer; otherwise, they are the same.

[0031] Comparative Example 4 Compared with Example 3, Comparative Example 4 differs in that o-chloroaniline is not used, and aniline is used instead of o-chloroaniline; otherwise, they are the same.

[0032] Comparative Example 5 Compared with Example 3, Comparative Example 5 differs in that it does not use a titanate coupling agent, but is otherwise identical.

[0033] Comparative Example 6 Compared with Example 3, Comparative Example 6 differs in that deionized water is not sprayed in step three, but all other steps are the same.

[0034] The modified wood samples obtained in Examples 1-3 and Comparative Examples 1-6 were tested as follows.

[0035] Compressive strength test: according to GB / T 1935-2009 "Test Method for Compressive Strength of Wood Along the Grain"; Antibacterial test: Escherichia coli was used as the strain. The modified wood sample was placed in a container with Escherichia coli cultured. After 24 hours, the bacterial growth on the surface of the modified wood sample was observed and the proportion of the surface of the modified wood sample where no bacteria grew was recorded. Hydrophobicity test: The water contact angle of the modified wood sample was measured; The test results are shown in Table 1.

[0036] Table 1 Test Results

[0037] Based on the test results in Table 1 Figures 3 to 11 As can be seen, compared with Comparative Examples 1-6, the modified wood prepared by the present invention has excellent antibacterial and water-resistant properties, and its compressive strength is excellent.

[0038] This invention utilizes a titanate coupling agent to hydrolyze and obtain a nano-titanium dioxide structure on the surface of wood. This enhances the strength and stiffness of the composite material, while also promoting the combination of the rough surface of the nano-titanium dioxide with the hydrophobic polymer to form a micro-nano-scale composite structure. This increases the contact angle, making the modified wood surface superhydrophobic and effectively inhibiting bacterial growth on the surface.

[0039] This invention utilizes the condensation reaction of acrolein and o-chloroaniline to generate a functional monomer containing unsaturated double bonds. This functional monomer participates in the polymerization reaction of hydroxyacrylamide and allyl glycidyl ether, enhancing intermolecular forces. Combined with the introduced benzene ring structure, it can significantly improve the compressive strength of modified wood. At the same time, it forms a hydrophobic polymer chain, which can effectively reduce the exposure of hydrophilic groups. The Schiff base in the functional monomer combines with chlorine, the hydrophobicity of the benzene ring, and the photo-antibacterial mechanism of titanium dioxide to improve the antibacterial activity of modified wood through multiple antibacterial mechanisms, thereby disrupting bacterial metabolism.

[0040] This invention uses allyl glycidyl ether as a reactant monomer. The epoxy groups contained therein form chemical bonds with the hydroxyl groups of hydroxyacrylamide and the hydroxyl groups on the wood surface to form a high-strength three-dimensional network, which significantly improves compressive strength and deformation resistance. The dense structure formed can significantly improve the hydrophobicity and antibacterial properties of modified wood. In addition, the epoxy groups can also form chemical forces with titanium dioxide, promoting more allyl glycidyl ether to participate in polymerization and facilitating the formation of a denser structure, thereby improving the compressive strength, superhydrophobicity and antibacterial properties of modified wood.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for modifying wood with highly stable composite nanomaterials, characterized in that, The process includes the following steps: Step 1: Clean and dry the wood to obtain pretreated wood; Step 2: Dissolve the functional monomer, hydroxyacrylamide and allyl glycidyl ether in anhydrous ethanol, add titanate coupling agent and initiator and stir to mix to obtain modified liquid; Step 3: Immerse the pretreated wood in the modified liquid for impregnation, remove the wood and spray deionized water on its surface, age it, heat and keep it warm, and then vacuum dry it to obtain the final product.

2. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that: In step one, the cleaning involves washing the wood surface with deionized water, and the drying involves drying at 85°C for 4-6 hours and at 100°C until constant weight.

3. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that: In step two, the stirring and mixing is carried out at a speed of 400-600 rpm for 15-20 minutes.

4. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that: In step two, the mass ratio of the functional monomer, hydroxyacrylamide, allyl glycidyl ether, titanate coupling agent, initiator and anhydrous ethanol is 6-8:2.0-2.5:1.4-1.8:1.2-1.5:0.20-0.22:30-40, and the initiator is initiator AIBN.

5. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that: In step three, the volume ratio of the pretreated wood to the modified liquid is 1:

6.

6. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that: In step three, the impregnation treatment consists of impregnation under vacuum at -0.08 MPa for 40-60 minutes, followed by impregnation under pressure at 1 MPa for 2.0-3.0 hours.

7. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that: In step three, the amount of deionized water sprayed is 0.4-0.5 times the weight gain of the pretreated wood after impregnation.

8. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that: In step three, the aging process is carried out at room temperature for 24-30 hours, the heating and heat preservation process is carried out at 80℃ for 6-8 hours and then at 110-120℃ for 1.0-1.5 hours, and the vacuum drying process is carried out to constant weight.

9. The process for modifying wood with highly stable composite nanomaterials according to claim 1, characterized in that, The preparation method of the functional monomer includes the following steps: Under an inert atmosphere, acrolein, acetic acid, and anhydrous ethanol are mixed, o-chloroaniline is added, and the mixture is heated and stirred, then evaporated by rotary evaporation and freeze-dried to obtain the final product.

10. The process for modifying wood with highly stable composite nanomaterials according to claim 9, characterized in that: The inert atmosphere is either nitrogen or argon, and the heating and stirring are carried out at 60-65℃ and 200-400 rpm for 4-6 hours. The mass ratio of acrolein, o-chloroaniline, acetic acid and anhydrous ethanol is 2.8-4.0:2.0-2.5:0.06-0.08:20-25.

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