Nanometer material modification process for improving wood stability

Abstract

The invention discloses a nano-material modification process for improving wood stability, which comprises the following steps: mixing wood with sodium hydroxide, sodium sulfite and deionized water to prepare a pretreatment solution, treating the wood with the pretreatment solution to increase the porosity of the wood, preparing pretreated wood, soaking the pretreated wood in a nano-material, and drying to obtain the nano-material modified wood. Under the action of air pressure, the nano material enters pores of the wood, temperature rise and heat preservation are carried out, the nano material is cured, wood modification is completed, a dual dynamic cross-linked network formed by the nano material is combined with rich hydrogen bonds of polyurethane, multi-layer physical-chemical cross-linked points can be constructed, and the wood modification effect is improved. A rigid dynamic covalent bond serves as a permanent cross-linking point to guarantee strength and modulus, and a hydrogen bond serves as a reversible physical cross-linking point and is preferentially broken to dissipate energy when being stressed, so that the material is endowed with high toughness, and the mechanical property of the treated wood is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of wood modification, and more specifically to a nanomaterial modification process for improving wood stability. Background Technology

[0002] Wood, a natural high-molecular-weight biomass material formed through long-term biological evolution, is widely used in construction, furniture making, energy conversion, packaging and transportation, and green chemicals, playing an irreplaceable role in the inheritance of human civilization and the progress of social development. Due to its renewable, lightweight, and environmentally friendly properties, wood is considered an ideal natural ecological material. However, its inherent porous structure and insufficient strength limit the functional applications of fast-growing timber, leading to its gradual replacement by materials such as metals, glass, and synthetic polymers. Therefore, researching new technologies and methods to overcome the inherent defects of wood is crucial for achieving its high-value utilization. Summary of the Invention

[0003] The purpose of this invention is to provide a nanomaterial modification process to improve the stability of wood and solve the problem of low mechanical properties of wood materials at present.

[0004] The objective of this invention can be achieved through the following technical solutions: A nanomaterial modification process for improving wood stability specifically includes the following steps: Step S1: Mix sodium hydroxide, sodium sulfite and deionized water evenly to prepare a pretreatment solution. Soak the wood in the pretreatment solution, heat to boiling, soak for 30 minutes, stop heating, let stand at room temperature, take out the wood, wash with deionized water until neutral, freeze dry to obtain pretreated wood. Step S2: Weigh the following raw materials in parts by weight: 15-20 parts polyester polyol, 30-40 parts hexamethylene diisocyanate, 5-10 parts phthalic anhydride, 0.5-0.8 parts modifying additive, 3-4 parts acrylic acid, 5-7 parts vinyl monomer, 5-7 parts butyl methacrylate, 4-15 parts hydroxyethyl methacrylate, 8-10 parts ethylene glycol butyl ether, 1-1.5 parts nano silica, 15-20 parts modified silicon oligomer, and 0.05-0.1 parts ammonium persulfate. Mix the raw materials evenly to obtain nanomaterials. Step S3: Immerse the pretreated wood in nanomaterials, vacuum for 20 minutes, release the vacuum and let stand for 5 minutes. Repeat twice. Then, heat-treat at 70-90℃ for 30-40 minutes, raise the temperature to 100-120℃ and heat-treat for 1-1.5 hours to complete the wood modification.

[0005] Furthermore, the ratio of sodium hydroxide, sodium sulfite, and deionized water used in step S1 is 2.5 mol: 0.4 mol: 1 L.

[0006] Furthermore, the modified additive is prepared by the following steps: Step A1: Mix phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water evenly, purge with nitrogen, and react at 120-150 r / min and 85-90℃ for 3-5 h. Then cool to 20-25℃ and react for 10-15 h to obtain sodium octaphenylcyclotetrasiloxane tetrasilanolate. Mix sodium octaphenylcyclotetrasiloxane tetrasilanolate, triethylamine, methyldichlorosilane and tetrahydrofuran evenly, and react at 150-200 r / min and 0℃ for 3-5 h. Then heat to 20-25℃ and react for 18-20 h to obtain dihydrocage-type silsesquioxane. Step A2: Dihydrocage-type silsesquioxane, 2-vinylpropane-1,3-diol, chloroplatinic acid and xylene are mixed and purged with nitrogen. The mixture is reacted for 6-8 hours at a rotation speed of 200-300 r / min and a temperature of 85-90℃ to obtain functionalized cage-type silsesquioxane. 4-Formylphenylboronic acid, functionalized cage-type silsesquioxane, 4A molecular sieve and xylene are mixed and purged with nitrogen. The mixture is reacted for 6-8 hours at a rotation speed of 200-300 r / min and a temperature of 115-120℃ to obtain modified cage-type silsesquioxane. Step A3: Mix modified cage-type silsesquioxane, ethylenediamine, anhydrous magnesium sulfate, and xylene, and purge with nitrogen. React at 200-300 r / min and 115-120℃ for 4-6 hours to obtain a pretreated additive. Mix the pretreated additive with xylene, purge with nitrogen, and stir at 600-800 r / min and 0-5℃. Add propyltriethoxysilane isocyanate and react for 1-1.5 hours. Then raise the temperature to 20-25℃ and continue the reaction for 8-10 hours to obtain the modified additive.

[0007] Furthermore, the ratio of phenyltrimethoxysilane, isopropanol, sodium hydroxide, and deionized water in step A1 is 120 mmol:120 mL:80 mmol:3 mL, and the ratio of octaphenylcyclotetrasiloxane tetrasilanolate sodium, triethylamine, methyldichlorosilane, and tetrahydrofuran is 12 g:4.5 mL:3.8 g:40 mL.

[0008] Further, in step A2, the molar ratio of dihydrocage-type silsesquioxane and 2-vinylpropane-1,3-diol is 1:2, the amount of chloroplatinic acid is 0.01% of the mass of 2-vinylpropane-1,3-diol, the molar ratio of 4-formylphenylboronic acid and functionalized cage-type silsesquioxane is 2:1, and the amount of 4A molecular sieve is 0.05% of the mass of 4-formylphenylboronic acid.

[0009] Furthermore, the molar ratio of the modified cage-type silsesquioxane and ethylenediamine mentioned in step A3 is n:n+1, where n is a natural number greater than 0, the amount of anhydrous magnesium sulfate is 0.03% of the mass of ethylenediamine, and the molar ratio of the amino group and propyltriethoxysilane isocyanate on the pretreatment additive is 1:1.

[0010] Furthermore, the modified silicon oligomer is prepared by the following steps: Step B1: Mix octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water, purge with nitrogen, and react at 120-150 r / min and 90-95℃ for 10-15 h. Then raise the temperature to 105-110℃ and continue the reaction for 2-3 h to obtain functionalized polysiloxane. Step B2: Mix functionalized polysiloxane, boron trifluoride ether, hydroquinone and xylene, purge with nitrogen, stir and add 3,4-epoxy-1-butene at a speed of 120-150 r / min and a temperature of 60-70℃, and react for 6-8 h to obtain pretreated polysiloxane. Step B3: Mix the pretreated polysiloxane, 3-mercaptopropyltrimethoxysilane, benzophenone and xylene evenly, and react for 30-40 minutes under the conditions of 200-300 r / min, 20-25℃ and 365nm ultraviolet light irradiation to obtain the modified silicon oligomer.

[0011] Furthermore, the ratio of octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water in step B1 is 1 mol: 0.2 mol: 1 mol: 1.5 mol: 20 mL.

[0012] Furthermore, in step B2, the molar ratio of the functionalized polysiloxane to 3,4-epoxy-1-butene is 1:4, the amount of boron trifluoride ether is 1% of the total mass of the functionalized polysiloxane and 3,4-epoxy-1-butene, and the amount of hydroquinone is 0.1% of the total mass of the functionalized polysiloxane and 3,4-epoxy-1-butene.

[0013] Furthermore, in step B3, the molar ratio of the double bond on the pretreated polysiloxane to 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 0.1% of the mass of 3-mercaptopropyltrimethoxysilane.

[0014] The beneficial effects of this invention are as follows: This application discloses a nanomaterial modification process for improving the stability of wood. Wood is first treated with a mixture of sodium hydroxide, sodium sulfite, and deionized water to obtain a pretreatment solution. The wood is then treated with this pretreatment solution to increase its porosity, resulting in pretreated wood. The following raw materials are weighed: polyester polyol, hexamethylene diisocyanate, phthalic anhydride, modifying additives, acrylic acid, vinyl monomer, butyl methacrylate, hydroxyethyl methacrylate, ethylene glycol butyl ether, nano-silica, modified silicon oligomer, and ammonium persulfate. These raw materials are mixed to obtain nanomaterials. The pretreated wood is then immersed in the nanomaterials, and under air pressure, the nanomaterials penetrate the pores of the wood. Heating and heat preservation are then applied to solidify the nanomaterials, completing the wood modification process.

[0015] The modified additive is prepared by hydrolysis and condensation of phenyltrimethylsiloxane to obtain sodium octaphenylcyclotetrasiloxane tetrasilanolate. The sodium octaphenylcyclotetrasiloxane tetrasilanolate is then reacted with methyldichlorosilane, causing the Si-Cl bonds on the sodium silanolate and methyldichlorosilane to react, yielding a dihydro-cage-type silsesquioxane. This dihydro-cage-type silsesquioxane is then reacted with 2-vinylpropane-1,3-diol, causing the Si-H bonds on the dihydro-cage-type silsesquioxane to react with the double bonds on the 2-vinylpropane-1,3-diol, yielding a functionalized cage-type silsesquioxane. The 4- Formylphenylboronic acid reacts with functionalized cage-like silsesquioxanes, causing the borate group on 4-formylphenylboronic acid to react with the diol on the functionalized cage-like silsesquioxane to form a five-membered ring borate ester structure, thus obtaining a modified cage-like silsesquioxane. The modified cage-like silsesquioxane is then reacted with ethylenediamine, causing the aldehyde group on the modified cage-like silsesquioxane to react with the amino group on the ethylenediamine to form an imine bond, thus obtaining a pretreatment additive. The pretreatment additive is then reacted with propyltriethoxysilane isocyanate, causing the amino group on the pretreatment additive to react with the isocyanate group on the propyltriethoxysilane, thus obtaining a modified additive.

[0016] Modified silicone oligomers are prepared by ring-opening octamethylcyclotetrasiloxane as a raw material and hydrolyzing and condensing it with 3-methacryloyloxypropylmethyldimethoxysilane, followed by end capping with 1,3-bis(aminopropyl)tetramethyldisiloxane to form polysiloxanes with double bonds in the side chains and amino groups at both ends, thus obtaining functionalized polysiloxanes. The functionalized polysiloxanes are then reacted with 3,4-epoxy-1-butene, causing the amino groups on the functionalized polysiloxanes to react with the epoxy groups on the 3,4-epoxy-1-butenes to form hydroxyl groups, thus obtaining pretreated polysiloxanes. The pretreated polysiloxanes are then reacted with 3-mercaptopropyltrimethoxysilane, causing the double bonds on the pretreated polysiloxanes to react with the mercapto groups on the 3-mercaptopropyltrimethoxysilanes, thus obtaining modified silicone oligomers.

[0017] After pretreatment and immersion in nanomaterials, two stages of high-temperature insulation are performed. First, the isocyanate and hydroxyl groups in the nanomaterials react to form a polyurethane network. Simultaneously, the addition of hydroxyethyl methacrylate introduces double bonds at the ends of the polyurethane molecules, enabling the polyurethane network to undergo free radical polymerization with acrylic acid, vinyl monomers, and butyl methacrylate, thus forming an interpenetrating network. The addition of modifying additives and nano-silica allows the nano-sized inorganic materials to penetrate the wood pores, further enhancing the mechanical properties of the wood. Furthermore, the modifying additives and modified silicon oligomers contain siloxane structures, which enhance absorption... Moisture in the air causes the siloxane structure to hydrolyze into silanol. The silanol can react with adjacent hydroxyl or silanol groups to further strengthen the crosslinking network. The borate ester structure and imine structure in the modified additive transform the crosslinking network into a dual dynamic crosslinking network. Combined with the abundant hydrogen bonds in polyurethane itself, it can construct multi-level physical-chemical crosslinking points. The rigid dynamic covalent bonds serve as permanent crosslinking points to ensure strength and modulus, while the hydrogen bonds, as reversible physical crosslinking points, preferentially break under stress to dissipate energy, thereby giving the material high toughness and significantly improving the mechanical properties of the treated wood. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: A nanomaterial modification process to improve the stability of wood, specifically including the following steps: Step S1: Mix sodium hydroxide, sodium sulfite and deionized water evenly to prepare a pretreatment solution. Soak the wood in the pretreatment solution, heat to boiling, soak for 30 minutes, stop heating, let stand at room temperature, take out the wood, wash with deionized water until neutral, freeze dry to obtain pretreated wood. Step S2: Weigh the following raw materials in parts by weight: 15 parts polyester polyol, 30 parts hexamethylene diisocyanate, 5 parts phthalic anhydride, 0.5 parts modifying additive, 3 parts acrylic acid, 5 parts vinyl monomer, 5 parts butyl methacrylate, 4 parts hydroxyethyl methacrylate, 8 parts ethylene glycol butyl ether, 1 part nano silica, 15 parts modified silicon oligomer and 0.05 parts ammonium persulfate. Mix the raw materials evenly to obtain nanomaterials. Step S3: Immerse the pretreated wood in nanomaterials, vacuum for 20 minutes, release the vacuum and let stand for 5 minutes. Repeat twice, then heat-treat at 70℃ for 30 minutes, raise the temperature to 100℃ and heat-treat for 1 hour to complete the wood modification.

[0020] The ratio of sodium hydroxide, sodium sulfite, and deionized water used in step S1 is 2.5 mol: 0.4 mol: 1 L.

[0021] The polyester polyol mentioned in step S2 is polyester diol CMA-1044, and the vinyl monomer is styrene.

[0022] The modified additive is prepared by the following steps: Step A1: Mix phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water evenly, purge with nitrogen, and react at 120 r / min and 85°C for 3 h. Then cool to 20°C and react for 10 h to obtain sodium octaphenylcyclotetrasiloxane tetrasilanolate. Mix sodium octaphenylcyclotetrasiloxane tetrasilanolate, triethylamine, methyldichlorosilane and tetrahydrofuran evenly, and react at 150 r / min and 0°C for 3 h. Then heat to 20°C and react for 18 h to obtain dihydrocage-type silsesquioxane. Step A2: Dihydrocage-type silsesquioxane, 2-vinylpropane-1,3-diol, chloroplatinic acid and xylene are mixed and purged with nitrogen. The mixture is reacted for 6 hours at a speed of 200 r / min and a temperature of 85 °C to obtain functionalized cage-type silsesquioxane. 4-Formylphenylboronic acid, functionalized cage-type silsesquioxane, 4A molecular sieve and xylene are mixed and purged with nitrogen. The mixture is reacted for 6 hours at a speed of 200 r / min and a temperature of 115 °C to obtain modified cage-type silsesquioxane. Step A3: Mix modified cage-type silsesquioxane, ethylenediamine, anhydrous magnesium sulfate, and xylene, and purge with nitrogen. React at 200 r / min and 115 °C for 4 h to obtain a pretreated additive. Mix the pretreated additive with xylene, purge with nitrogen, and stir at 600 r / min and 0 °C. Add propyltriethoxysilane isocyanate and react for 1 h. Then raise the temperature to 20 °C and continue the reaction for 8 h to obtain the modified additive.

[0023] The ratio of phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water used in step A1 is 120 mmol: 120 mL: 80 mmol: 3 mL, and the ratio of octaphenylcyclotetrasiloxane tetrasilanolate sodium, triethylamine, methyldichlorosilane and tetrahydrofuran is 12 g: 4.5 mL: 3.8 g: 40 mL.

[0024] In step A2, the molar ratio of dihydro-cage-type silsesquioxane to 2-vinylpropane-1,3-diol is 1:2, the amount of chloroplatinic acid is 0.01% of the mass of 2-vinylpropane-1,3-diol, the molar ratio of 4-formylphenylboronic acid to functionalized cage-type silsesquioxane is 2:1, and the amount of 4A molecular sieve is 0.05% of the mass of 4-formylphenylboronic acid.

[0025] The molar ratio of the modified cage-like silsesquioxane and ethylenediamine mentioned in step A3 is 1:2, the amount of anhydrous magnesium sulfate is 0.03% of the mass of ethylenediamine, and the molar ratio of the amino group and propyltriethoxysilane isocyanate on the pretreatment additive is 1:1.

[0026] The modified silicon oligomer is prepared by the following steps: Step B1: Mix octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water, purge with nitrogen, and react at 120-150 r / min and 90-95℃ for 10-15 h. Then raise the temperature to 105-110℃ and continue the reaction for 2-3 h to obtain functionalized polysiloxane. Step B2: Mix functionalized polysiloxane, boron trifluoride ether, hydroquinone and xylene, purge with nitrogen, stir and add 3,4-epoxy-1-butene at a speed of 120-150 r / min and a temperature of 60-70℃, and react for 6-8 h to obtain pretreated polysiloxane. Step B3: Mix the pretreated polysiloxane, 3-mercaptopropyltrimethoxysilane, benzophenone and xylene evenly, and react for 30-40 minutes under the conditions of 200-300 r / min, 20-25℃ and 365nm ultraviolet light irradiation to obtain the modified silicon oligomer.

[0027] The ratio of octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water in step B1 is 1 mol: 0.2 mol: 1 mol: 1.5 mol: 20 mL.

[0028] The molar ratio of functionalized polysiloxane and 3,4-epoxy-1-butene in step B2 is 1:4, the amount of boron trifluoride ether is 1% of the total mass of functionalized polysiloxane and 3,4-epoxy-1-butene, and the amount of hydroquinone is 0.1% of the total mass of functionalized polysiloxane and 3,4-epoxy-1-butene.

[0029] In step B3, the molar ratio of the double bond on the pretreated polysiloxane to 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 0.1% of the mass of 3-mercaptopropyltrimethoxysilane.

[0030] Example 2: A nanomaterial modification process to improve wood stability, specifically including the following steps: Step S1: Mix sodium hydroxide, sodium sulfite and deionized water evenly to prepare a pretreatment solution. Soak the wood in the pretreatment solution, heat to boiling, soak for 30 minutes, stop heating, let stand at room temperature, take out the wood, wash with deionized water until neutral, freeze dry to obtain pretreated wood. Step S2: Weigh the following raw materials in parts by weight: 18 parts polyester polyol, 35 parts hexamethylene diisocyanate, 8 parts phthalic anhydride, 0.6 parts modifying additive, 3.5 parts acrylic acid, 6 parts vinyl monomer, 6 parts butyl methacrylate, 10 parts hydroxyethyl methacrylate, 9 parts ethylene glycol butyl ether, 1.3 parts nano silica, 18 parts modified silicon oligomer and 0.08 parts ammonium persulfate. Mix the raw materials evenly to obtain nanomaterials. Step S3: Immerse the pretreated wood in nanomaterials, vacuum for 20 minutes, release the vacuum and let stand for 5 minutes. Repeat twice, then heat-treat at 80℃ for 35 minutes, raise the temperature to 110℃ and heat-treat for 1.3 hours to complete the wood modification.

[0031] The ratio of sodium hydroxide, sodium sulfite, and deionized water used in step S1 is 2.5 mol: 0.4 mol: 1 L.

[0032] The polyester polyol mentioned in step S2 is polyester diol CMA-1044, and the vinyl monomer is acrylonitrile.

[0033] The modified additive is prepared by the following steps: Step A1: Mix phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water evenly, purge with nitrogen, and react at 120 r / min and 90°C for 4 h. Then cool to 20°C and react for 15 h to obtain sodium octaphenylcyclotetrasiloxane tetrasilanolate. Mix sodium octaphenylcyclotetrasiloxane tetrasilanolate, triethylamine, methyldichlorosilane and tetrahydrofuran evenly, and react at 150 r / min and 0°C for 4 h. Then heat to 25°C and react for 19 h to obtain dihydrocage-type silsesquioxane. Step A2: Dihydrocage-type silsesquioxane, 2-vinylpropane-1,3-diol, chloroplatinic acid and xylene are mixed and purged with nitrogen. The mixture is reacted for 7 hours at a speed of 300 r / min and a temperature of 85 °C to obtain functionalized cage-type silsesquioxane. 4-Formylphenylboronic acid, functionalized cage-type silsesquioxane, 4A molecular sieve and xylene are mixed and purged with nitrogen. The mixture is reacted for 7 hours at a speed of 200 r / min and a temperature of 120 °C to obtain modified cage-type silsesquioxane. Step A3: Mix modified cage-type silsesquioxane, ethylenediamine, anhydrous magnesium sulfate, and xylene, and purge with nitrogen. React at 200 r / min and 120°C for 5 h to obtain a pretreated additive. Mix the pretreated additive with xylene, purge with nitrogen, and stir at 600 r / min and 3°C. Add propyltriethoxysilane isocyanate and react for 1.5 h. Then raise the temperature to 20°C and continue the reaction for 9 h to obtain the modified additive.

[0034] The ratio of phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water used in step A1 is 120 mmol: 120 mL: 80 mmol: 3 mL, and the ratio of octaphenylcyclotetrasiloxane tetrasilanolate sodium, triethylamine, methyldichlorosilane and tetrahydrofuran is 12 g: 4.5 mL: 3.8 g: 40 mL.

[0035] In step A2, the molar ratio of dihydro-cage-type silsesquioxane to 2-vinylpropane-1,3-diol is 1:2, the amount of chloroplatinic acid is 0.01% of the mass of 2-vinylpropane-1,3-diol, the molar ratio of 4-formylphenylboronic acid to functionalized cage-type silsesquioxane is 2:1, and the amount of 4A molecular sieve is 0.05% of the mass of 4-formylphenylboronic acid.

[0036] The molar ratio of the modified cage-like silsesquioxane and ethylenediamine mentioned in step A3 is 2:3, the amount of anhydrous magnesium sulfate is 0.03% of the mass of ethylenediamine, and the molar ratio of the amino group and propyltriethoxysilane isocyanate on the pretreatment additive is 1:1.

[0037] The modified silicon oligomer is prepared by the following steps: Step B1: Octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water were mixed and purged with nitrogen. The mixture was reacted at 120 r / min and 95 °C for 13 h. The temperature was then raised to 108 °C and the reaction was continued for 3 h to obtain functionalized polysiloxane. Step B2: Functionalized polysiloxane, boron trifluoride ether, hydroquinone and xylene are mixed and purged with nitrogen. Under nitrogen protection, 3,4-epoxy-1-butene is added while stirring at a speed of 120 r / min and a temperature of 65°C. The mixture is reacted for 7 h to obtain pretreated polysiloxane. Step B3: Mix the pretreated polysiloxane, 3-mercaptopropyltrimethoxysilane, benzophenone and xylene evenly, and react for 35 min under the conditions of 200 r / min rotation speed, 25℃ temperature and 365nm ultraviolet light irradiation to obtain the modified silicon oligomer.

[0038] The ratio of octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water in step B1 is 1 mol: 0.2 mol: 1 mol: 1.5 mol: 20 mL.

[0039] The molar ratio of functionalized polysiloxane and 3,4-epoxy-1-butene in step B2 is 1:4, the amount of boron trifluoride ether is 1% of the total mass of functionalized polysiloxane and 3,4-epoxy-1-butene, and the amount of hydroquinone is 0.1% of the total mass of functionalized polysiloxane and 3,4-epoxy-1-butene.

[0040] In step B3, the molar ratio of the double bond on the pretreated polysiloxane to 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 0.1% of the mass of 3-mercaptopropyltrimethoxysilane.

[0041] Example 3: A nanomaterial modification process to improve wood stability, specifically including the following steps: Step S1: Mix sodium hydroxide, sodium sulfite and deionized water evenly to prepare a pretreatment solution. Soak the wood in the pretreatment solution, heat to boiling, soak for 30 minutes, stop heating, let stand at room temperature, take out the wood, wash with deionized water until neutral, freeze dry to obtain pretreated wood. Step S2: Weigh the following raw materials in parts by weight: 20 parts polyester polyol, 40 parts hexamethylene diisocyanate, 10 parts phthalic anhydride, 0.8 parts modifying additive, 4 parts acrylic acid, 7 parts vinyl monomer, 7 parts butyl methacrylate, 15 parts hydroxyethyl methacrylate, 10 parts ethylene glycol butyl ether, 1.5 parts nano silica, 20 parts modified silicon oligomer and 0.1 parts ammonium persulfate. Mix the raw materials evenly to obtain nanomaterials. Step S3: Immerse the pretreated wood in nanomaterials, vacuum for 20 minutes, release the vacuum and let stand for 5 minutes. Repeat twice, then heat-treat at 90℃ for 40 minutes, raise the temperature to 120℃ and heat-treat for 1.5 hours to complete the wood modification.

[0042] The ratio of sodium hydroxide, sodium sulfite, and deionized water used in step S1 is 2.5 mol: 0.4 mol: 1 L.

[0043] The polyester polyol mentioned in step S2 is polyester diol CMA-1044, and the vinyl monomer is a mixture of styrene and acrylonitrile in a mass ratio of 1:1.

[0044] The modified additive is prepared by the following steps: Step A1: Mix phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water evenly, purge with nitrogen, and react at 150 r / min and 90°C for 5 h. Then cool to 25°C and react for 15 h to obtain sodium octaphenylcyclotetrasiloxane tetrasilanolate. Mix sodium octaphenylcyclotetrasiloxane tetrasilanolate, triethylamine, methyldichlorosilane and tetrahydrofuran evenly, and react at 200 r / min and 0°C for 5 h. Then heat to 25°C and react for 20 h to obtain dihydrocage-type silsesquioxane. Step A2: Dihydrocage-type silsesquioxane, 2-vinylpropane-1,3-diol, chloroplatinic acid and xylene are mixed and purged with nitrogen. The mixture is reacted for 8 hours at a speed of 300 r / min and a temperature of 90 °C to obtain functionalized cage-type silsesquioxane. 4-Formylphenylboronic acid, functionalized cage-type silsesquioxane, 4A molecular sieve and xylene are mixed and purged with nitrogen. The mixture is reacted for 8 hours at a speed of 300 r / min and a temperature of 120 °C to obtain modified cage-type silsesquioxane. Step A3: Mix modified cage-type silsesquioxane, ethylenediamine, anhydrous magnesium sulfate, and xylene, and purge with nitrogen. React at 300 r / min and 120°C for 6 h to obtain a pretreated additive. Mix the pretreated additive with xylene, purge with nitrogen, and stir at 800 r / min and 5°C. Add propyltriethoxysilane isocyanate and react for 1-1.5 h. Then raise the temperature to 25°C and continue the reaction for 10 h to obtain the modified additive.

[0045] The ratio of phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water used in step A1 is 120 mmol: 120 mL: 80 mmol: 3 mL, and the ratio of octaphenylcyclotetrasiloxane tetrasilanolate sodium, triethylamine, methyldichlorosilane and tetrahydrofuran is 12 g: 4.5 mL: 3.8 g: 40 mL.

[0046] In step A2, the molar ratio of dihydro-cage-type silsesquioxane to 2-vinylpropane-1,3-diol is 1:2, the amount of chloroplatinic acid is 0.01% of the mass of 2-vinylpropane-1,3-diol, the molar ratio of 4-formylphenylboronic acid to functionalized cage-type silsesquioxane is 2:1, and the amount of 4A molecular sieve is 0.05% of the mass of 4-formylphenylboronic acid.

[0047] The molar ratio of the modified cage-like silsesquioxane and ethylenediamine mentioned in step A3 is 3:4, the amount of anhydrous magnesium sulfate is 0.03% of the mass of ethylenediamine, and the molar ratio of amino and propyltriethoxysilane on the pretreatment additive is 1:1.

[0048] The modified silicon oligomer is prepared by the following steps: Step B1: Octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water are mixed and purged with nitrogen. The mixture is then reacted at 150 r / min and 95 °C for 15 h. The temperature is then raised to 110 °C and the reaction is continued for 3 h to obtain functionalized polysiloxane. Step B2: Functionalized polysiloxane, boron trifluoride ether, hydroquinone and xylene are mixed and purged with nitrogen. Under nitrogen protection, 3,4-epoxy-1-butene is added while stirring at a speed of 150 r / min and a temperature of 70°C. The mixture is reacted for 8 h to obtain pretreated polysiloxane. Step B3: Mix the pretreated polysiloxane, 3-mercaptopropyltrimethoxysilane, benzophenone and xylene evenly, and react for 40 min under the conditions of 300 r / min rotation speed, 25℃ temperature and 365nm ultraviolet light irradiation to obtain the modified silicon oligomer.

[0049] The ratio of octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water in step B1 is 1 mol: 0.2 mol: 1 mol: 1.5 mol: 20 mL.

[0050] The molar ratio of functionalized polysiloxane and 3,4-epoxy-1-butene in step B2 is 1:4, the amount of boron trifluoride ether is 1% of the total mass of functionalized polysiloxane and 3,4-epoxy-1-butene, and the amount of hydroquinone is 0.1% of the total mass of functionalized polysiloxane and 3,4-epoxy-1-butene.

[0051] In step B3, the molar ratio of the double bond on the pretreated polysiloxane to 3-mercaptopropyltrimethoxysilane is 1:1, and the amount of benzophenone used is 0.1% of the mass of 3-mercaptopropyltrimethoxysilane.

[0052] Comparative Example 1: This comparative example did not include any modifying additives compared to Example 1, but the remaining steps were the same.

[0053] Comparative Example 2: Compared with Example 1, this comparative example uses a mixture of dihydro-cage-type silsesquioxane, allylamine, chloroplatinic acid and xylene, under nitrogen protection, and reacts for 6 hours at a rotation speed of 200 r / min and a temperature of 85°C to obtain a product that replaces the pretreatment additive. The remaining steps are the same.

[0054] Comparative Example 3: In this comparative example, the pretreated polysiloxane is replaced with modified silicon oligomers instead of the pretreated polysiloxane, while the remaining steps are the same as in Example 1.

[0055] The wood obtained from Examples 1-3 and Comparative Examples 1-3 was selected as basswood and tested according to ASTM D790-17 standard. The test span was 30 mm, and the upper indenter was pressed down at a speed of 5 mm / min. In the bending test, a rectangular specimen with dimensions of 50 mm × 4 mm × 1.5 mm was used. The tensile test was conducted according to ASTM D638-14 standard, with a loading speed of 2 mm / min. The test samples were cut into dumbbell shapes using an ASTM D638 V-shaped die cutter. The test results are shown in Table 1.

[0056] Table 1

[0057] As shown in Table 1, this application has excellent mechanical properties.

[0058] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A nanomaterial modification process for improving the stability of wood, characterized in that: Specifically, the steps include the following: Step S1: Mix sodium hydroxide, sodium sulfite and deionized water evenly to prepare a pretreatment solution. Soak the wood in the pretreatment solution and heat it to boiling. After soaking, stop heating and let it stand at room temperature. Take out the wood, wash it with deionized water until neutral, and freeze dry it to obtain pretreated wood. Step S2: Weigh the following raw materials in parts by weight: 15-20 parts polyester polyol, 30-40 parts hexamethylene diisocyanate, 5-10 parts phthalic anhydride, 0.5-0.8 parts modifying additive, 3-4 parts acrylic acid, 5-7 parts vinyl monomer, 5-7 parts butyl methacrylate, 4-15 parts hydroxyethyl methacrylate, 8-10 parts ethylene glycol butyl ether, 1-1.5 parts nano silica, 15-20 parts modified silicon oligomer, and 0.05-0.1 parts ammonium persulfate. Mix the raw materials evenly to obtain nanomaterials. Step S3: Immerse the pretreated wood in nanomaterials, vacuum for 20 minutes, release the vacuum and let stand for 5 minutes. Repeat twice. Then, heat-treat at 70-90℃ for 30-40 minutes, raise the temperature to 100-120℃ and heat-treat for 1-1.5 hours to complete the wood modification.

2. The nanomaterial modification process for improving wood stability according to claim 1, characterized in that: The ratio of sodium hydroxide, sodium sulfite, and deionized water used in step S1 is 2.5 mol: 0.4 mol: 1 L.

3. The nanomaterial modification process for improving wood stability according to claim 1, characterized in that: The modified additive is prepared by the following steps: Step A1: Mix phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water evenly, purge with nitrogen gas and react to obtain sodium octaphenylcyclotetrasiloxane tetrasiloxane. Mix sodium octaphenylcyclotetrasiloxane tetrasiloxane, triethylamine, methyldichlorosilane and tetrahydrofuran and react to obtain dihydro-cage-type silsesquioxane. Step A2: Dihydro-cage-type silsesquioxane, 2-vinylpropane-1,3-diol, chloroplatinic acid and xylene are mixed and reacted under nitrogen protection to obtain functionalized cage-type silsesquioxane. 4-Formylphenylboronic acid, functionalized cage-type silsesquioxane, 4A molecular sieve and xylene are mixed and reacted under nitrogen protection to obtain modified cage-type silsesquioxane. Step A3: Mix modified cage-type silsesquioxane, ethylenediamine, anhydrous magnesium sulfate and xylene, purge with nitrogen, and react to obtain a pretreatment additive. Mix the pretreatment additive and xylene, purge with nitrogen, stir and add propyltriethoxysilane isocyanate, and react to obtain a modified additive.

4. The nanomaterial modification process for improving wood stability according to claim 3, characterized in that: The ratio of phenyltrimethoxysilane, isopropanol, sodium hydroxide and deionized water used in step A1 is 120 mmol: 120 mL: 80 mmol: 3 mL, and the ratio of octaphenylcyclotetrasiloxane tetrasilanolate sodium, triethylamine, methyldichlorosilane and tetrahydrofuran is 12 g: 4.5 mL: 3.8 g: 40 mL.

5. The nanomaterial modification process for improving wood stability according to claim 3, characterized in that: The molar ratio of dihydro-cage silsesquioxane and 2-vinylpropane-1,3-diol in step A2 is 1:2, and the molar ratio of 4-formylphenylboronic acid and functionalized cage silsesquioxane is 2:

1.

6. The nanomaterial modification process for improving wood stability according to claim 3, characterized in that: The molar ratio of the modified cage-type silsesquioxane and ethylenediamine mentioned in step A3 is n:n+1, where n is a natural number greater than 0, and the molar ratio of the amino group and propyltriethoxysilane isocyanate on the pretreatment additive is 1:

1.

7. The nanomaterial modification process for improving wood stability according to claim 1, characterized in that: The modified silicon oligomer is prepared by the following steps: Step B1: Mix octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water, and purge with nitrogen to carry out the reaction to obtain functionalized polysiloxane. Step B2: Functionalized polysiloxane, boron trifluoride ether, hydroquinone and xylene are mixed, nitrogen gas is introduced for protection, 3,4-epoxy-1-butene is added while stirring, and the reaction is carried out to obtain pretreated polysiloxane. Step B3: The pretreated polysiloxane, 3-mercaptopropyltrimethoxysilane, benzophenone and xylene are mixed and reacted under ultraviolet light to obtain the modified silicon oligomer.

8. The nanomaterial modification process for improving wood stability according to claim 7, characterized in that: The ratio of octamethylcyclotetrasiloxane, 3-methacryloyloxypropylmethyldimethoxysilane, 1,3-bis(aminopropane)tetramethyldisiloxane, tetramethylammonium hydroxide and deionized water in step B1 is 1 mol: 0.2 mol: 1 mol: 1.5 mol: 20 mL.

9. The nanomaterial modification process for improving wood stability according to claim 7, characterized in that: The molar ratio of the functionalized polysiloxane and 3,4-epoxy-1-butene described in step B2 is 1:

4.

10. The nanomaterial modification process for improving wood stability according to claim 7, characterized in that: The molar ratio of the double bond on the pretreated polysiloxane and 3-mercaptopropyltrimethoxysilane in step B3 is 1:1.

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