Waterproof fiber composite board and preparation method thereof

Abstract

The application discloses a waterproof fiber composite board and a preparation method thereof and belongs to the technical field of fiber composite boards. Fir wood fibers, maleic anhydride, benzoyl peroxide and N,N-dimethylaniline are mixed and stirred to obtain pretreated wood fibers; the pretreated wood fibers are mixed with phenolic resin with a solid content of 50% to obtain a wood matrix material, and modified pollen, modified lotus leaf wax, stannous octoate and modified aerogel are added and mixed to obtain functional slurry; the functional slurry is poured into a mold and subjected to hot pressing treatment to obtain the waterproof fiber composite board. The modified aerogel is chemically bonded to the pretreated wood fibers and the modified pollen through isocyanate groups, a continuous heat preservation network is constructed to endow the heat preservation property; the phenolic resin, the modified pollen and the modified lotus leaf wax form a double waterproof barrier to solve the problem that the hydrophobic components are prone to migration; and the components synergize to make the product have excellent waterproofness, antibacterial property, heat preservation property, mechanical property and thermal stability.

Description

Technical Field

[0001] This invention relates to the field of fiber composite board technology, and specifically to a waterproof fiber composite board and its preparation method. Background Technology

[0002] With the rapid development of the global green building materials industry, wood fiber composite boards made from fast-growing timber such as fir have seen their application in the building decoration and home furnishing sectors expand due to their wide availability of raw materials, good environmental compatibility, and mechanical properties suitable for furniture manufacturing, interior decoration, and other applications. However, natural wood fibers are rich in hydrophilic groups such as hydroxyl and carboxyl groups, and there are natural pores between the fibers. This leads to traditional wood fiber composite boards generally facing problems such as high water absorption, susceptibility to microbial attack by Escherichia coli, Staphylococcus aureus, etc., resulting in mold and deterioration. In addition, their hydrophobic properties tend to degrade over time during long-term use. At the same time, the interfacial bonding force between wood fibers and binders such as phenolic resin is insufficient, often resulting in the composite board's mechanical strength and thermal stability failing to meet the requirements of humid environments or applications with high durability requirements. These inherent defects seriously restrict the expansion of its application scope.

[0003] To address the aforementioned issues, existing technologies often employ modification by adding chemical waterproofing agents or inorganic antibacterial agents. However, traditional waterproofing agents rely heavily on physical adsorption to adhere to the fiber or resin surface, and are prone to leaching and loss after long-term immersion or use, resulting in poor hydrophobic durability. Inorganic antibacterial agents, on the other hand, have high surface energy and are prone to agglomeration in composite systems, which reduces antibacterial efficiency and may also damage the microstructural integrity of the composite board, indirectly affecting its mechanical properties. Furthermore, current research largely focuses on optimizing single functions, lacking synergistic regulation of waterproofing, antibacterial properties, mechanical properties, and thermal stability. Moreover, with the increasing demand for integrated building materials such as insulated decorative panels, traditional wood fiber composite boards suffer from a lack of insulation properties: some products are not designed for insulation, requiring additional insulation layers, leading to complex construction and increased costs; a few attempts to add ordinary aerogel, perlite, or other insulation materials have failed due to insufficient interfacial bonding between the insulation components and wood fibers and bonding resins, easily causing agglomeration and breakage, creating insulation blind spots, while simultaneously damaging the original waterproof structure, resulting in increased water absorption and decreased mechanical strength, failing to achieve multi-dimensional synergistic performance of waterproofing, antibacterial properties, thermal insulation, and mechanical stability.

[0004] Patent CN108687902A discloses a corrosion-resistant and antibacterial medium-density fiberboard and its manufacturing process. The corrosion-resistant and antibacterial medium-density fiberboard is composed of wood fibers, adhesives, anti-corrosion and antibacterial agents, and paraffin wax. The corrosion-resistant and antibacterial medium-density fiberboard is obtained by impregnating wood fibers with antibacterial agents such as boric acid and copper ethanolamine, and coating the surface with paraffin wax for waterproofing. However, in this invention, the paraffin wax only physically coats the fiber surface. After immersion, the contact angle retention rate is only 50%~60%, and the paraffin wax is easy to soften at high temperatures, resulting in a sharp drop in waterproof performance. The paraffin wax coating hinders the bonding between fibers and resin, which may affect the mechanical properties of the fiberboard.

[0005] Against this backdrop, how to fully explore the environmental protection characteristics and functional potential of natural biomass resources, and combine them with efficient and green modification processes to achieve synergistic improvement in the multi-dimensional performance of wood fiber composite boards, has become a core research direction in the industry. Natural pollen, with its porous structure and good biocompatibility, can serve as a functional carrier; lotus leaf wax, due to its naturally micro-nano rough structure, possesses excellent hydrophobic potential. If these biomass materials can be given stronger interfacial bonding capabilities and functional synergy through reasonable chemical modification, forming a stable composite system with wood fiber and bonding resin, it is expected not only to simultaneously improve the waterproof and antibacterial properties of the composite board, but also to take into account mechanical strength, thermal stability, and thermal insulation. This would lead to the development of a new type of waterproof fiber composite board with excellent comprehensive performance and environmental friendliness, meeting the market's urgent demand for high-performance, green, integrated thermal insulation and decorative building materials. Summary of the Invention

[0006] To address the challenge of balancing hydrophobicity and mechanical properties in existing waterproof fiber composite boards, this invention provides a high-performance waterproof fiber composite board by modifying pollen, modifying lotus leaf wax, pretreating wood fibers, and optimizing hot-pressing parameters. Specifically, the technical solution of this invention includes the following steps: A method for preparing a waterproof fiber composite board, the method comprising the following steps: Pretreated wood fibers are obtained by mixing and stirring cedar wood fibers, maleic anhydride, benzoyl peroxide and N,N-dimethylaniline. Pretreated wood fibers and phenolic resin are mixed to obtain a wood matrix material. Modified pollen, modified lotus leaf wax, stannous octoate and modified aerogel are added and mixed to obtain a functional slurry. The waterproof fiber composite board is obtained by pouring functional slurry into a mold and hot-pressing it.

[0007] Furthermore, the weight ratio of the cedar wood fiber, maleic anhydride, benzoyl peroxide and N,N-dimethylaniline is 100:2~4:0.1~0.2:0.02~0.03.

[0008] Furthermore, the conditions for the mixed stirring reaction of the cedar wood fibers, maleic anhydride, benzoyl peroxide and N,N-dimethylaniline include a reaction temperature of 65~75℃, a reaction speed of 400r / min and a reaction time of 4~6h.

[0009] Furthermore, the solid content of the phenolic resin is 50%.

[0010] Furthermore, the method for preparing the modified pollen includes the following steps: Sunflower pollen was successively treated with deionized water and petroleum ether to obtain defatted pollen; Pretreated pollen was obtained by mixing and stirring defatted pollen, isocyanate-propyltriethoxysilane and perfluorooctyltriethoxysilane; The modified pollen was prepared by mixing pretreated pollen and nano zinc oxide, followed by ultrasonic treatment and stirring reaction.

[0011] Further, the sunflower pollen is treated sequentially with deionized water and petroleum ether under the following conditions: 50 parts by weight of sunflower pollen is dispersed in 200 parts by weight of deionized water, stirred at 50°C and 1000 r / min for 2 hours, and then filtered to obtain a first solid. The first solid is dispersed in 200 parts by weight of petroleum ether, stirred at 60°C and 1000 r / min for 8 hours, and then filtered to obtain a second solid. The second solid is washed three times with deionized water and then vacuum dried at 50°C for 12 hours.

[0012] Furthermore, the weight ratio of the defatted pollen, isocyanate-propyltriethoxysilane, and perfluorooctyltriethoxysilane is 100:3~6:15~18.

[0013] Furthermore, the conditions for the mixed and stirred reaction of the defatted pollen, isocyanate-propyltriethoxysilane and perfluorooctyltriethoxysilane include a reaction temperature of 45-55°C, a reaction speed of 600 r / min, and a reaction time of 6-8 h.

[0014] Furthermore, the weight ratio of the pretreated pollen to nano zinc oxide is 30:2.5~5.5.

[0015] Furthermore, the conditions for the ultrasonic treatment include an ultrasonic power of 300W and an ultrasonic time of 30-50 minutes.

[0016] Furthermore, the conditions for the stirring reaction of the pretreated pollen and nano zinc oxide include a reaction temperature of 50-60°C, a reaction speed of 400 r / min, and a reaction time of 8-12 h.

[0017] Furthermore, the preparation method of the modified lotus leaf wax includes the following steps: Lotus leaf blocks were subjected to ultrasonic soaking and then allowed to stand to obtain lotus leaf wax extract. Modified graphene was obtained by mixing and stirring graphene oxide, octadecylamine, dicyclohexylcarbodiimide and hydroxybenzotriazole. The modified lotus leaf wax was prepared by mixing lotus leaf wax extract, modified graphene, isophorone diisocyanate and dibutyltin dilaurate, followed by ultrasonic treatment and stirring reaction, and then pulverizing.

[0018] Furthermore, the conditions for the ultrasonic immersion treatment include immersion solvent chloroform, ultrasonic power of 250W, and ultrasonic time of 30min.

[0019] Further, the weight ratio of the graphene oxide, octadecylamine, dicyclohexylcarbodiimide and hydroxybenzotriazole is 0.2~0.3:0.5~0.7:0.1~0.15:0.1~0.15.

[0020] Furthermore, the conditions for the mixed stirring reaction of graphene oxide, octadecylamine, dicyclohexylcarbodiimide and hydroxybenzotriazole include a reaction temperature of 75-85°C, a reaction speed of 500 r / min and a reaction time of 6-8 h.

[0021] Furthermore, the weight ratio of the lotus leaf wax extract, modified graphene, isophorone diisocyanate and dibutyltin dilaurate is 20~25:0.6~0.9:1.2~1.5:0.03~0.05.

[0022] Furthermore, the conditions under which the lotus leaf wax extract, modified graphene, isophorone diisocyanate, and dibutyltin dilaurate are mixed and subjected to ultrasonic treatment and stirring reaction include ultrasonic treatment at a power of 300~350W for 30~50min, followed by stirring reaction at 800r / min for 4~5h.

[0023] Furthermore, the pulverization conditions include a pulverization speed of 10,000 r / min and a pulverization time of 10 min.

[0024] Furthermore, the preparation method of the modified aerogel includes the following steps: The modified aerogel is prepared by mixing silica aerogel and isocyanate-based propyltriethoxysilane and stirring at 500 r / min for 4-5 h at 50-60 °C. After filtration and drying, the modified aerogel is obtained.

[0025] Furthermore, the weight ratio of the silica aerogel to isocyanate-propyltriethoxysilane is 100:8~12.

[0026] Furthermore, the weight ratio of the pretreated wood fiber, phenolic resin, modified pollen, modified lotus leaf wax, stannous octoate and modified aerogel is 100:80~90:20~25:8~12:0.2~0.25:5~8.

[0027] Furthermore, the conditions for mixing the pretreated wood fibers and phenolic resin include a mixing speed of 600 r / min and a mixing time of 15-20 min.

[0028] Furthermore, the conditions for adding modified pollen, modified lotus leaf wax, stannous octoate and modified aerogel and mixing and stirring include a mixing speed of 800 r / min and a mixing time of 2~4 h.

[0029] Furthermore, the hot pressing conditions include a hot pressing temperature of 150~170℃, a pressure of 10MPa, and a hot pressing time of 2~3h.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In this invention, sunflower pollen is defatted with water and petroleum ether to remove water-soluble and fat-soluble impurities, exposing the hydroxyl groups on the pollen surface to obtain defatted pollen. The siloxane in the silane is hydrolyzed and condenses with the hydroxyl groups on the defatted pollen surface to form covalent bonds, introducing perfluorooctyl and isocyanate groups to obtain pretreated pollen. Nano zinc oxide is loaded onto the surface of the pretreated pollen through hydrogen bonding to construct a micron-nano rough surface, enhancing hydrophobic stability and renewal, and fully utilizing the natural structural advantages of pollen to obtain modified pollen. Lotus leaf extract is extracted by chloroform to retain natural hydrophobicity. Octadecylamine is grafted onto the surface of graphene oxide through an amidation reaction to improve its hydrophobicity and obtain modified graphene. Isophorone diisocyanate Modified lotus leaf wax is obtained by cross-linking with lotus leaf wax extract and the hydroxyl groups on the surface of modified graphene to form a three-dimensional network, which enhances mechanical and hydrophobic barrier properties. Pretreated cedar wood fibers are grafted with maleic anhydride to obtain pretreated fibers, which enhance compatibility with phenolic resin and reduce water absorption. The pretreated wood fibers are mixed with phenolic resin to obtain wood matrix material. Modified pollen and modified lotus leaf wax are added, and functional pulp is obtained by reacting isocyanate groups with hydroxyl and carboxyl groups. The pretreated fibers, modified pollen, and modified lotus leaf wax form a chemical cross-linking network. Phenolic resin is encapsulated in the network through physical filling and π-π interaction to form an integral structure. Finally, waterproof fiber composite board is obtained by hot pressing and curing.

[0031] (2) This invention uses the reaction of isocyanate with the carboxyl groups of pretreated wood fibers and the hydroxyl groups of modified pollen to connect modified pollen and modified lotus leaf wax with cedar fibers, which helps to solve the problem of easy migration of hydrophobic components and ensures the durability of the hydrophobic interface; the dense structure of phenolic resin, the multi-level rough surface of modified pollen and the hydrophobic film of modified lotus leaf wax form a dual barrier of macroscopic barrier and microscopic hydrophobicity, and the components are chemically bonded together to form a whole, so water molecules cannot penetrate the interior and are difficult to adhere to the surface; the micro-nano structure of modified pollen can fill the gaps between cedar fibers and resin, and its low surface energy characteristics help to improve hydrophobicity; the continuous hydrophobic film of modified lotus leaf wax and the protrusions of modified pollen form The three-dimensional barrier network, with the former blocking moisture contact and the latter supporting the membrane structure and reducing wear, can also synergize with the antibacterial properties of modified pollen to solve the mold problem. Single pollen lacks a continuous hydrophobic layer, and the wax film formed by single lotus leaf wax lacks a rough structure. However, when combined, the modified pollen protrusions can create a rough surface, and the modified lotus leaf wax provides low surface energy, achieving a lotus leaf-like effect for hydrophobicity. The modified pollen protrusions can also reduce the wear of the modified lotus leaf wax. The continuous hydrophobic layer of the modified lotus leaf wax compensates for the shortcomings of the modified pollen particles, such as easy gaps and incomplete waterproofing. At the same time, its excellent thermal stability also improves the problem of limited thermal stability of modified pollen, avoiding the degradation of the hydrophobic performance of the composite system under high temperature environment.

[0032] (3) In this invention, the modified aerogel component is modified by isocyanate-propyltriethoxysilane. The introduced isocyanate groups can chemically bond with the carboxyl groups of the pretreated wood fibers and the hydroxyl groups of the modified pollen, thus achieving a stable combination with the composite system. The nanoporous structure of the modified aerogel has a low thermal conductivity, which can build a continuous thermal insulation barrier network inside the composite board. In addition, the chemical bonding between the modified aerogel and the pretreated wood fibers and modified pollen can enhance the structural integrity of the composite system. While improving the thermal insulation performance, it can also synergistically improve the bending strength and thermal stability of the composite board, so that the product meets the multi-dimensional performance requirements of the thermal insulation decorative board. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0034] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0035] Preparation Example 1: The preparation method of modified pollen includes the following steps: 50 parts by weight of sunflower pollen were dispersed in 200 parts by weight of deionized water, stirred at 50°C and 1000 r / min for 2 h, and then filtered to obtain the first solid. The first solid was dispersed in 200 parts by weight of petroleum ether, stirred at 60°C and 1000 r / min for 8 h, and then filtered to obtain the second solid. The second solid was washed three times with deionized water and dried under vacuum at 50°C for 12 h to obtain defatted pollen. 100 parts by weight of defatted pollen, 3 parts by weight of isocyanate-propyltriethoxysilane and 15 parts by weight of perfluorooctyltriethoxysilane were dispersed in 300 parts by weight of ethanol solution. The mixture was stirred at 600 r / min at 45 °C for 6 h under a nitrogen atmosphere. The solid was then collected by filtration and dried under vacuum at 60 °C for 8 h to obtain pretreated pollen. 30 parts by weight of pretreated pollen and 2.5 parts by weight of nano zinc oxide were dispersed in 150 parts by weight of isopropanol. After ultrasonic treatment at 300W for 30 min, the mixture was stirred at 50℃ and 400r / min for 8 h. The solid was collected by filtration and vacuum dried at 50℃ for 12 h to obtain modified pollen.

[0036] Preparation Example 2: The preparation method of modified pollen includes the following steps: 50 parts by weight of sunflower pollen were dispersed in 200 parts by weight of deionized water, stirred at 50°C and 1000 r / min for 2 h, and then filtered to obtain the first solid. The first solid was dispersed in 200 parts by weight of petroleum ether, stirred at 60°C and 1000 r / min for 8 h, and then filtered to obtain the second solid. The second solid was washed three times with deionized water and dried under vacuum at 50°C for 12 h to obtain defatted pollen. 100 parts by weight of defatted pollen, 4 parts by weight of isocyanate-propyltriethoxysilane and 16 parts by weight of perfluorooctyltriethoxysilane were dispersed in 300 parts by weight of ethanol solution. The mixture was stirred at 600 r / min at 48 °C for 6.5 h under a nitrogen atmosphere. The solid was then collected by filtration and dried under vacuum at 60 °C for 8 h to obtain pretreated pollen. 30 parts by weight of pretreated pollen and 3.5 parts by weight of nano zinc oxide were dispersed in 150 parts by weight of isopropanol. After ultrasonic treatment at 300W for 35 min, the mixture was stirred at 52℃ and 400r / min for 9 h. The solid was collected by filtration and vacuum dried at 50℃ for 12 h to obtain modified pollen.

[0037] Preparation Example 3: The preparation method of modified pollen includes the following steps: 50 parts by weight of sunflower pollen were dispersed in 200 parts by weight of deionized water, stirred at 50°C and 1000 r / min for 2 h, and then filtered to obtain the first solid. The first solid was dispersed in 200 parts by weight of petroleum ether, stirred at 60°C and 1000 r / min for 8 h, and then filtered to obtain the second solid. The second solid was washed three times with deionized water and dried under vacuum at 50°C for 12 h to obtain defatted pollen. 100 parts by weight of defatted pollen, 5 parts by weight of isocyanate-propyltriethoxysilane and 17 parts by weight of perfluorooctyltriethoxysilane were dispersed in 300 parts by weight of ethanol solution. The mixture was stirred at 600 r / min at 51 °C for 7 h under a nitrogen atmosphere. The solid was then collected by filtration and dried under vacuum at 60 °C for 8 h to obtain pretreated pollen. 30 parts by weight of pretreated pollen and 4.5 parts by weight of nano zinc oxide were dispersed in 150 parts by weight of isopropanol. After ultrasonic treatment at 300W for 40 min, the mixture was stirred at 57℃ and 400r / min for 11 h. The solid was collected by filtration and vacuum dried at 50℃ for 12 h to obtain modified pollen.

[0038] Preparation Example 4: The preparation method of modified pollen includes the following steps: 50 parts by weight of sunflower pollen were dispersed in 200 parts by weight of deionized water, stirred at 50°C and 1000 r / min for 2 h, and then filtered to obtain the first solid. The first solid was dispersed in 200 parts by weight of petroleum ether, stirred at 60°C and 1000 r / min for 8 h, and then filtered to obtain the second solid. The second solid was washed three times with deionized water and dried under vacuum at 50°C for 12 h to obtain defatted pollen. 100 parts by weight of defatted pollen, 6 parts by weight of isocyanate-propyltriethoxysilane and 18 parts by weight of perfluorooctyltriethoxysilane were dispersed in 300 parts by weight of ethanol solution. The mixture was stirred at 600 r / min at 55 °C for 8 h under a nitrogen atmosphere. The solid was then collected by filtration and dried under vacuum at 60 °C for 8 h to obtain pretreated pollen. 30 parts by weight of pretreated pollen and 5.5 parts by weight of nano zinc oxide were dispersed in 150 parts by weight of isopropanol. After ultrasonic treatment at 300W for 50 min, the mixture was stirred at 400 r / min at 60℃ for 12 h. The solid was collected by filtration and vacuum dried at 50℃ for 12 h to obtain modified pollen.

[0039] Preparation Example 5: The preparation method of defatted pollen includes the following steps: 50 parts by weight of sunflower pollen were dispersed in 200 parts by weight of deionized water, stirred at 1000 r / min for 2 h at 50 °C, and then filtered to obtain the first solid. The first solid was dispersed in 200 parts by weight of petroleum ether, stirred at 1000 r / min for 8 h at 60 °C, and then filtered to obtain the second solid. The second solid was washed three times with deionized water and dried under vacuum at 50 °C for 12 h to obtain defatted pollen.

[0040] Preparation Example 6: The preparation method of modified lotus leaf wax includes the following steps: Lotus leaves were soaked in deionized water and ultrasonically cleaned for 10 minutes at 200W to remove dirt. After drying at 25℃ for 30 minutes, they were cut into 1cm×1cm pieces to obtain lotus leaf blocks. The lotus leaf blocks were ultrasonically soaked in chloroform at 250W for 30 minutes at a solid-liquid ratio of 1:10. After treatment, the wax-containing solution was collected by filtration. The wax-containing solution was stirred and dispersed at 800r / min at 25℃ for 24 hours and then allowed to stand for 1 hour. The supernatant was collected to obtain lotus leaf wax extract. 0.2 parts by weight of graphene oxide were dispersed in 40 parts by weight of DMF, and 0.5 parts by weight of octadecylamine, 0.1 parts by weight of dicyclohexylcarbodiimide and 0.1 parts by weight of hydroxybenzotriazole were added. The mixture was stirred at 75°C and 500 r / min for 6 h under nitrogen protection. After the reaction was completed, the solid was collected by centrifugation at 10000 r / min for 20 min to obtain modified graphene. After melting 20 parts by weight of lotus leaf wax extract at 80℃, 0.6 parts by weight of modified graphene, 1.2 parts by weight of isophorone diisocyanate and 0.03 parts by weight of dibutyltin dilaurate were added. The mixture was ultrasonically treated at 300W for 30 min, and then stirred at 800 r / min for 4 h. After the reaction was completed, the mixture was cooled to 25℃ and pulverized at 10000 r / min for 10 min using a high-speed pulverizer to obtain the primary lotus leaf wax. The primary lotus leaf wax was washed three times with anhydrous ethanol and then vacuum dried at 50℃ for 8 h to obtain the modified lotus leaf wax.

[0041] Preparation Example 7: The preparation method of modified lotus leaf wax includes the following steps: Lotus leaves were soaked in deionized water and ultrasonically cleaned for 10 minutes at 200W to remove dirt. After drying at 25℃ for 30 minutes, they were cut into 1cm×1cm pieces to obtain lotus leaf blocks. The lotus leaf blocks were ultrasonically soaked in chloroform at 250W for 30 minutes at a solid-liquid ratio of 1:10. After treatment, the wax-containing solution was collected by filtration. The wax-containing solution was stirred and dispersed at 800r / min at 25℃ for 24 hours and then allowed to stand for 1 hour. The supernatant was collected to obtain lotus leaf wax extract. 0.23 parts by weight of graphene oxide were dispersed in 40 parts by weight of DMF, and 0.57 parts by weight of octadecylamine, 0.12 parts by weight of dicyclohexylcarbodiimide and 0.12 parts by weight of hydroxybenzotriazole were added. The mixture was stirred at 500 r / min for 6.5 h at 80 °C under nitrogen protection. After the reaction was completed, the solid was collected by centrifugation at 10000 r / min for 20 min to obtain modified graphene. After melting 22 parts by weight of lotus leaf wax extract at 82℃, 0.7 parts by weight of modified graphene, 1.3 parts by weight of isophorone diisocyanate and 0.035 parts by weight of dibutyltin dilaurate were added. The mixture was ultrasonically treated at 310W for 35 min, and then stirred at 800 r / min for 4.3 h. After the reaction was completed, the mixture was cooled to 25℃ and pulverized at 10000 r / min for 10 min using a high-speed pulverizer to obtain the primary lotus leaf wax. The primary lotus leaf wax was washed three times with anhydrous ethanol and then vacuum dried at 50℃ for 8 h to obtain the modified lotus leaf wax.

[0042] Preparation Example 8: The preparation method of modified lotus leaf wax includes the following steps: Lotus leaves were soaked in deionized water and ultrasonically cleaned for 10 minutes at 200W to remove dirt. After drying at 25℃ for 30 minutes, they were cut into 1cm×1cm pieces to obtain lotus leaf blocks. The lotus leaf blocks were ultrasonically soaked in chloroform at 250W for 30 minutes at a solid-liquid ratio of 1:10. After treatment, the wax-containing solution was collected by filtration. The wax-containing solution was stirred and dispersed at 800r / min at 25℃ for 24 hours and then allowed to stand for 1 hour. The supernatant was collected to obtain lotus leaf wax extract. 0.27 parts by weight of graphene oxide were dispersed in 40 parts by weight of DMF, and 0.62 parts by weight of octadecylamine, 0.14 parts by weight of dicyclohexylcarbodiimide and 0.14 parts by weight of hydroxybenzotriazole were added. The mixture was stirred at 82°C and 500 r / min for 7 h under nitrogen protection. After the reaction was completed, the solid was collected by centrifugation at 10000 r / min for 20 min to obtain modified graphene. After melting 24 parts by weight of lotus leaf wax extract at 83℃, 0.8 parts by weight of modified graphene, 1.4 parts by weight of isophorone diisocyanate and 0.04 parts by weight of dibutyltin dilaurate were added. The mixture was ultrasonically treated at 330W for 40 min, and then stirred at 800 r / min for 4.6 h. After the reaction was completed, the mixture was cooled to 25℃ and pulverized at 10000 r / min for 10 min using a high-speed pulverizer to obtain the primary lotus leaf wax. The primary lotus leaf wax was washed three times with anhydrous ethanol and then vacuum dried at 50℃ for 8 h to obtain the modified lotus leaf wax.

[0043] Preparation Example 9: The preparation method of modified lotus leaf wax includes the following steps: Lotus leaves were soaked in deionized water and ultrasonically cleaned for 10 minutes at 200W to remove dirt. After drying at 25℃ for 30 minutes, they were cut into 1cm×1cm pieces to obtain lotus leaf blocks. The lotus leaf blocks were ultrasonically soaked in chloroform at 250W for 30 minutes at a solid-liquid ratio of 1:10. After treatment, the wax-containing solution was collected by filtration. The wax-containing solution was stirred and dispersed at 800r / min at 25℃ for 24 hours and then allowed to stand for 1 hour. The supernatant was collected to obtain lotus leaf wax extract. 0.3 parts by weight of graphene oxide were dispersed in 40 parts by weight of DMF, and 0.7 parts by weight of octadecylamine, 0.15 parts by weight of dicyclohexylcarbodiimide and 0.15 parts by weight of hydroxybenzotriazole were added. The mixture was stirred at 85°C and 500 r / min for 8 h under nitrogen protection. After the reaction was completed, the solid was collected by centrifugation at 10000 r / min for 20 min to obtain modified graphene. After melting 25 parts by weight of lotus leaf wax extract at 85℃, 0.9 parts by weight of modified graphene, 1.5 parts by weight of isophorone diisocyanate and 0.05 parts by weight of dibutyltin dilaurate were added. The mixture was ultrasonically treated at 350W for 50 min, and then stirred at 800 r / min for 5 h. After the reaction was completed, the mixture was cooled to 25℃ and pulverized at 10000 r / min for 10 min using a high-speed pulverizer to obtain the primary lotus leaf wax. The primary lotus leaf wax was washed three times with anhydrous ethanol and then vacuum dried at 50℃ for 8 h to obtain the modified lotus leaf wax.

[0044] Preparation Example 10: The preparation method of modified lotus leaf wax includes the following steps: Lotus leaves were soaked in deionized water and ultrasonically cleaned for 10 minutes at 200W to remove dirt. After drying at 25℃ for 30 minutes, they were cut into 1cm×1cm pieces to obtain lotus leaf blocks. The lotus leaf blocks were ultrasonically soaked in chloroform at 250W for 30 minutes at a solid-liquid ratio of 1:10. After treatment, the wax-containing solution was collected by filtration. The wax-containing solution was stirred and dispersed at 800r / min at 25℃ for 24 hours and then allowed to stand for 1 hour. The supernatant was collected to obtain lotus leaf wax extract. After melting 25 parts by weight of lotus leaf wax extract at 85℃, 0.9 parts by weight of graphene oxide, 1.5 parts by weight of isophorone diisocyanate and 0.05 parts by weight of dibutyltin dilaurate were added. The mixture was ultrasonically treated at 350W for 50 min, and then stirred at 800 r / min for 5 h. After the reaction was completed, the mixture was cooled to 25℃ and pulverized at 10000 r / min for 10 min using a high-speed pulverizer to obtain the primary lotus leaf wax. The primary lotus leaf wax was washed three times with anhydrous ethanol and then vacuum dried at 50℃ for 8 h to obtain the modified lotus leaf wax.

[0045] Preparation Example 11: The preparation method of lotus leaf wax extract includes the following steps: Lotus leaves were soaked in deionized water and ultrasonically cleaned for 10 minutes at 200W to remove dirt. After drying at 25℃ for 30 minutes, they were cut into 1cm×1cm pieces to obtain lotus leaf blocks. The lotus leaf blocks were ultrasonically soaked in chloroform at 250W for 30 minutes at a solid-liquid ratio of 1:10. After treatment, the wax-containing solution was collected by filtration. The wax-containing solution was stirred and dispersed at 800r / min at 25℃ for 24 hours and then allowed to stand for 1 hour. The supernatant was collected to obtain lotus leaf wax extract.

[0046] Preparation Example 12: The preparation method of modified aerogel includes the following steps: 100 parts by weight of silica aerogel were dispersed in 300 parts by weight of anhydrous ethanol, and 8 parts by weight of isocyanate-propyltriethoxysilane were added. The mixture was stirred at 50°C and 500 r / min for 4 h. The solid was collected by filtration and dried under vacuum at 60°C for 6 h to obtain the modified aerogel.

[0047] Preparation Example 13: The preparation method of modified aerogel includes the following steps: 100 parts by weight of silica aerogel were dispersed in 300 parts by weight of anhydrous ethanol, and 10 parts by weight of isocyanate-propyltriethoxysilane were added. The mixture was stirred at 55°C and 500 r / min for 4.5 h. The solid was collected by filtration and dried under vacuum at 60°C for 6 h to obtain the modified aerogel.

[0048] Preparation Example 14: The preparation method of modified aerogel includes the following steps: 100 parts by weight of silica aerogel were dispersed in 300 parts by weight of anhydrous ethanol, and 12 parts by weight of isocyanate-propyltriethoxysilane were added. The mixture was stirred at 60°C and 500 r / min for 5 h. The solid was collected by filtration and dried under vacuum at 60°C for 6 h to obtain the modified aerogel.

[0049] Example 1: A method for preparing a waterproof fiber composite board includes the following steps: 100 parts by weight of Chinese fir wood fiber were dispersed in 80 parts by weight of anhydrous ethanol, and 2 parts by weight of maleic anhydride, 0.1 parts by weight of benzoyl peroxide and 0.02 parts by weight of N,N-dimethylaniline were added. The mixture was stirred at 65°C and 400 r / min for 4 h. After the reaction was completed, the solid was collected by filtration and dried at 105°C until the moisture content was less than 5% to obtain pretreated wood fiber. 100 parts by weight of pretreated wood fiber and 80 parts by weight of phenolic resin (solid content 50%) were mixed and stirred at 600 r / min for 15 min to obtain wood matrix material. 20 parts by weight of modified pollen prepared in Preparation Example 1, 8 parts by weight of modified lotus leaf wax prepared in Preparation Example 6, 0.2 parts by weight of stannous octoate and 5 parts by weight of modified aerogel prepared in Preparation Example 12 were added and stirred at 800 r / min for 2 h to obtain functional slurry. The functional slurry is poured into a mold and pre-pressed at 10 MPa for 10 minutes. Then, the temperature is raised to 150℃ and hot-pressed at 10 MPa for 2 hours. After cooling to 26℃, the waterproof fiber composite board is demolded.

[0050] Example 2: A method for preparing a waterproof fiber composite board includes the following steps: 105 parts by weight of Chinese fir wood fiber were dispersed in 80 parts by weight of anhydrous ethanol, and 2.5 parts by weight of maleic anhydride, 0.12 parts by weight of benzoyl peroxide and 0.023 parts by weight of N,N-dimethylaniline were added. The mixture was stirred at 70°C and 400 r / min for 4.5 h. After the reaction was completed, the solid was collected by filtration and dried at 105°C until the moisture content was less than 5% to obtain pretreated wood fiber. 100 parts by weight of pretreated wood fiber and 83 parts by weight of phenolic resin (solid content 50%) were mixed and stirred at 600 r / min for 16 min to obtain wood matrix material. 22 parts by weight of modified pollen prepared in Preparation Example 2, 9 parts by weight of modified lotus leaf wax prepared in Preparation Example 7, 0.21 parts by weight of stannous octoate and 6 parts by weight of modified aerogel prepared in Preparation Example 12 were added and stirred at 800 r / min for 2.5 h to obtain functional slurry. The functional slurry is poured into a mold and pre-pressed at 10 MPa for 10 minutes. Then, the temperature is raised to 155℃ and hot-pressed at 10 MPa for 2.3 hours. After cooling to 26℃, the waterproof fiber composite board is demolded.

[0051] Example 3: A method for preparing a waterproof fiber composite board includes the following steps: 110 parts by weight of Chinese fir wood fiber were dispersed in 80 parts by weight of anhydrous ethanol, and 3 parts by weight of maleic anhydride, 0.15 parts by weight of benzoyl peroxide and 0.026 parts by weight of N,N-dimethylaniline were added. The mixture was stirred at 72°C and 400 r / min for 5 h. After the reaction was completed, the solid was collected by filtration and dried at 105°C until the moisture content was less than 5% to obtain pretreated wood fiber. 100 parts by weight of pretreated wood fiber and 87 parts by weight of phenolic resin (solid content 50%) were mixed and stirred at 600 r / min for 18 min to obtain wood matrix material. 24 parts by weight of modified pollen prepared in Preparation Example 3, 11 parts by weight of modified lotus leaf wax prepared in Preparation Example 8, 0.23 parts by weight of stannous octoate and 7 parts by weight of modified aerogel prepared in Preparation Example 13 were added and stirred at 800 r / min for 3 h to obtain functional slurry. The functional slurry is poured into a mold and pre-pressed at 10 MPa for 10 minutes. Then, the temperature is raised to 160℃ and hot-pressed at 10 MPa for 3 hours. After cooling to 26℃, the waterproof fiber composite board is demolded.

[0052] Example 4: A method for preparing a waterproof fiber composite board includes the following steps: 120 parts by weight of Chinese fir wood fiber were dispersed in 80 parts by weight of anhydrous ethanol, and 4 parts by weight of maleic anhydride, 0.2 parts by weight of benzoyl peroxide and 0.03 parts by weight of N,N-dimethylaniline were added. The mixture was stirred at 75°C and 400 r / min for 6 h. After the reaction was completed, the solid was collected by filtration and dried at 105°C until the moisture content was less than 5% to obtain pretreated wood fiber. 100 parts by weight of pretreated wood fiber and 90 parts by weight of phenolic resin (solid content 50%) were mixed and stirred at 600 r / min for 20 min to obtain wood matrix material. 25 parts by weight of modified pollen prepared in Preparation Example 4, 12 parts by weight of modified lotus leaf wax prepared in Preparation Example 9, 0.25 parts by weight of stannous octoate and 8 parts by weight of modified aerogel prepared in Preparation Example 14 were added and stirred at 800 r / min for 4 h to obtain functional slurry. The functional slurry is poured into a mold and pre-pressed at 10 MPa for 10 minutes. Then, the temperature is raised to 170℃ and maintained at 10 MPa for 3 hours of hot pressing. After cooling to 26℃, the waterproof fiber composite board is demolded.

[0053] Comparative Example 1: A method for preparing a waterproof fiber composite board includes the following steps: The modified lotus leaf wax prepared in Preparation Example 9 of Example 4 was replaced with the modified lotus leaf wax prepared in Preparation Example 10, and all other operations were the same as in Example 4.

[0054] Comparative Example 2: A method for preparing a waterproof fiber composite board includes the following steps: Replace 100 parts by weight of pretreated wood fiber in Example 4 with 100 parts by weight of cedar wood fiber, and keep all other operations the same as in Example 4.

[0055] Comparative Example 3: A method for preparing a waterproof fiber composite board includes the following steps: The modified pollen prepared in Example 4 was replaced with the defatted pollen prepared in Example 5, and all other operations were the same as in Example 4.

[0056] Comparative Example 4: A method for preparing a waterproof fiber composite board includes the following steps: The modified lotus leaf wax obtained in Preparation Example 9 of Example 4 was replaced with the lotus leaf wax extract obtained in Preparation Example 11, and all other operations were the same as in Example 4.

[0057] Comparative Example 5: A method for preparing a waterproof fiber composite board includes the following steps: 120 parts by weight of Chinese fir wood fiber were dispersed in 80 parts by weight of anhydrous ethanol, and 4 parts by weight of maleic anhydride, 0.2 parts by weight of benzoyl peroxide and 0.03 parts by weight of N,N-dimethylaniline were added. The mixture was stirred at 75°C and 400 r / min for 6 h. After the reaction was completed, the solid was collected by filtration and dried at 105°C until the moisture content was less than 5% to obtain pretreated wood fiber. 100 parts by weight of pretreated wood fiber and 90 parts by weight of phenolic resin (solid content 50%) were mixed and stirred at 600 r / min for 20 min to obtain wood matrix material. 25 parts by weight of modified pollen prepared in Preparation Example 4, 12 parts by weight of modified lotus leaf wax prepared in Preparation Example 9, 0.25 parts by weight of stannous octoate and 8 parts by weight of modified aerogel prepared in Preparation Example 14 were added and stirred at 800 r / min for 4 h to obtain functional slurry. The functional slurry is poured into a mold and pre-pressed at 10 MPa for 10 minutes. Then, it is heated to 120°C and hot-pressed at 5 MPa for 1 hour. After cooling to 26°C, it is demolded to obtain a waterproof fiber composite board.

[0058] Comparative Example 6: A method for preparing a waterproof fiber composite board includes the following steps: The modified aerogel prepared in Example 14 of Example 4 was replaced with silica aerogel, and all other operations were the same as in Example 4.

[0059] Performance testing: The properties of the waterproof fiber composite boards prepared in Examples 1-4 and Comparative Examples 1-6 were tested using the following methods: Water absorption test: Cut the waterproof fiber composite board into 50mm×50mm×board thickness samples, dry them in an oven at 105℃ to constant weight (m0), soak them in deionized water at 25℃ for 24 hours, blot the surface moisture with filter paper, weigh them (m1), and calculate the water absorption rate. Water absorption rate (%) = (m1-m0) / m0 × 100%; Water contact angle test: Using a contact angle measuring instrument, 5μL of deionized water was dropped onto the surface of the waterproof fiber composite board, and the static contact angle was measured; Hydrophobic durability test: Immerse the sample in deionized water at 40℃ for 72 hours, remove and dry to constant weight, repeat the water contact angle test, and calculate the contact angle retention rate after immersion: Contact angle retention rate after immersion (%) = Contact angle after immersion / Initial contact angle × 100%; Bending strength test: Cut the waterproof fiber composite board into 200mm×25mm×board thickness specimens and test their bending strength using a universal testing machine at a loading speed of 5mm / min. Thermal stability: In a nitrogen atmosphere, at a heating rate of 10℃ / min, within a heating range of 30~600℃, the temperature at which 5% mass loss is achieved is recorded using a thermogravimetric analyzer. Thermal conductivity test: The thermal conductivity of the waterproof fiber composite board was tested using the heat flow meter method, referring to the test method in GB / T 10294-2008. Antibacterial rate test: Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 29213) were selected as test bacteria. The waterproof fiber composite board was cut into 5mm×50mm pieces, sterilized, and then inoculated with bacterial suspension (10). 6 The bacterial suspension (CFU / mL) was incubated at 37°C for 24 h, and the viable bacterial count (C) was counted after elution. A blank sample (bacterial suspension only, C0) was also prepared simultaneously. The antibacterial rate was calculated. Antibacterial rate (%) = (C0 - C) / C0 × 100%; The test results are shown in Tables 1 and 2.

[0060] Table 1

[0061] Table 2

[0062] (1) As can be seen from the test results in Tables 1 and 2, the waterproof fiber composite boards prepared in Examples 1 to 4 of the present invention have good performance, while the performance of the waterproof fiber composite boards prepared in Comparative Examples 1 to 6 has been reduced to varying degrees. (2) The reason for the performance degradation of Comparative Example 1 may be that unmodified graphene oxide was used instead of modified graphene oxide during the preparation of modified lotus leaf wax, and the octadecylamine-amidation reaction was not carried out. The amidation modification of octadecylamine can not only impart hydrophobic groups to the surface of graphene oxide, but also achieve chemical cross-linking between graphene and lotus leaf wax through the reaction of amino groups with isophorone diisocyanate. However, unmodified graphene oxide is prone to agglomeration due to its dense surface hydroxyl groups, and cannot be uniformly dispersed in the molten lotus leaf wax. This not only destroys the original micro-nano rough hydrophobic structure of lotus leaf wax, but also loses the role of graphene as a catalyst. The "thermal barrier" effect results in an incomplete hydrophobic interface on the surface of the composite board, making it easy for water to penetrate. At the same time, the thermal stability decreases due to the failure of graphene dispersion. In addition, the uncrosslinked structure can cause hydrophobic components to easily fall off during immersion, resulting in poor hydrophobic durability. Antibacterial components are also more easily lost due to loose interfacial bonding, ultimately leading to a significant reduction in antibacterial rate. Agglomerated graphene oxide may hinder the dispersion of modified aerogel in the composite system, preventing the aerogel from forming a continuous thermal insulation network. The gaps created by agglomeration may become channels for water penetration, affecting the waterproof effect. (3) The reason for the performance reduction of Comparative Example 2 may be that maleic anhydride, benzoyl peroxide and N,N-dimethylaniline were not added during the pretreatment of wood fibers. Untreated fir fibers were used directly. Maleic anhydride was used as a coupling agent to introduce active groups on the surface of wood fibers through grafting reaction, thereby enhancing the interfacial bonding force between the fiber and phenolic resin. The surface of untreated fibers lacked active sites, and the binding with the resin was only physical adsorption. There were a lot of gaps at the interface. These gaps became channels for water penetration. At the same time, the composite board was prone to cracking at the interface when under stress. The loosely bonded structure also made it easier for volatile components to be released during thermal decomposition. Furthermore, the antibacterial and hydrophobic functional components were difficult to adhere stably, which led to a double decrease in antibacterial rate and hydrophobic durability. Untreated fibers could not form a stable bond with the modified aerogel. The aerogel agglomerated at the interfacial gaps, destroying the continuity of the thermal insulation network. (4) The reason for the performance reduction of Comparative Example 3 may be that the defatted pollen modified with only defatted unsilane and nano zinc oxide was replaced with the modified pollen. The modification with isocyanate-propyltriethoxysilane and perfluorooctyltriethoxysilane can enhance the binding between pollen and resin and improve hydrophobicity through perfluorinated groups. Nano zinc oxide is the core antibacterial component. The defatted pollen lacks the above modification process. On the one hand, the lack of perfluorinated hydrophobic groups leads to a decrease in the overall hydrophobicity of the composite plate. On the other hand, the lack of nano zinc oxide greatly reduces the antibacterial sites. At the same time, the unsilane-modified pollen has a weaker binding force with the resin, which will slightly weaken the interfacial bonding strength and indirectly lead to a slight decrease in bending strength. The thermal stability is also slightly reduced due to the lack of the thermal stability synergistic effect of nano zinc oxide. The modified pollen may form a pore complementary filling with the modified aerogel through silane modification. The pollen fills the micron gaps and the aerogel fills the nano gaps. The defatted pollen has no active sites modified with silane, and the synergistic effect with the aerogel fails. The composite plate has residual micropores and the thermal conductivity increases. (5) The reason for the performance reduction in Comparative Example 4 may be that the lotus leaf wax extract modified with only chloroform extraction and graphene and isocyanate was used instead of the modified lotus leaf wax. The lotus leaf wax extract modified with only chloroform extraction only retains the basic wax components and lacks the key functional enhancements in the modification process: modified graphene can enhance the hydrophobic effect through micro-nano rough structure and improve thermal stability; isophorone diisocyanate can make the lotus leaf wax form a more stable network structure through cross-linking reaction, reducing dissolution during soaking. The unmodified lotus leaf wax has neither the synergistic effect of hydrophobicity and thermal stability of graphene nor the anti-dissolution ability of cross-linked structure, resulting in a significant decrease in the hydrophobicity, thermal stability and hydrophobic durability of the composite board; at the same time, the uncross-linked wax is loosely bound to the resin, which will also slightly affect the bending strength, and the adhesion stability of the antibacterial components will also be reduced due to the loose interface binding; the modified lotus leaf wax can be bound to the modified aerogel through the cross-linked network to avoid direct contact with water; the lotus leaf wax extract has no encapsulation ability, the aerogel surface easily adsorbs water, the thermal insulation network is easily damaged, and it may also increase the water penetration path; (6) The reason for the performance reduction of Comparative Example 5 may be that the hot pressing parameters of the composite board were changed to 120℃, 5MPa, 1h, which is much lower than 170℃, 10MPa, 3h of Example 4. The core function of hot pressing is to promote the full curing and cross-linking of phenolic resin and to promote the wood fiber, modified pollen, and modified lotus leaf wax to form a tightly bonded overall structure. Too low temperature, insufficient pressure, and too short time will cause the phenolic resin to fail to cure completely. Not only will the adhesive force of the resin itself decrease significantly, but it will also fail to tightly wrap the functional components with the fibers. The uncured resin will form a large number of pores inside the composite board, which will become channels for rapid water penetration. The loose structure makes the composite board very easy to crack when subjected to force. The uncured resin molecular chains are more likely to decompose when heated, and all functional components are very easy to fall off due to the loose structure. Ultimately, the antibacterial rate and hydrophobic durability are reduced to the lowest level. The uncured resin cannot fix the modified aerogel, and the aerogel breaks apart with the pores. The loose structure cannot transmit the force, the bending strength is reduced, and the thermal stability is also reduced due to the easy decomposition of the uncured resin. (7) The reason for the performance reduction of Comparative Example 6 may be that the aerogel was not modified with isocyanate-based propyltriethoxysilane, resulting in the lack of surface-active isocyanate groups; the modified aerogel forms a continuous heat-insulating network by bonding the isocyanate groups with the carboxyl groups of the pretreated fibers and the hydroxyl groups of the modified pollen; the unmodified aerogel has no active groups on its surface and relies only on physical mixing and dispersion, which makes it easy to agglomerate and destroy the continuity of the heat-insulating network; the agglomerated aerogel generates new pores inside the composite plate, which become water permeation channels; the unbonded aerogel cannot work with the modified pollen to fill the gaps, resulting in reduced hydrophobic durability; the aerogel without chemical bonding cannot enhance the integrity of the system, resulting in reduced bending strength, loss of thermal stability due to aerogel agglomeration, and reduced thermal barrier effect.

[0063] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for preparing a waterproof fiber composite board, characterized in that, The preparation method includes the following steps: Pretreated wood fibers are obtained by mixing and stirring cedar wood fibers, maleic anhydride, benzoyl peroxide and N,N-dimethylaniline. Pretreated wood fibers and phenolic resin with a solid content of 50% are mixed to obtain a wood matrix material. Modified pollen, modified lotus leaf wax, stannous octoate and modified aerogel are added and mixed to obtain a functional slurry. The waterproof fiber composite board is obtained by pouring functional slurry into a mold and hot-pressing it. The method for preparing the modified pollen includes the following steps: Sunflower pollen was successively treated with deionized water and petroleum ether to obtain defatted pollen; Pretreated pollen was obtained by mixing and stirring defatted pollen, isocyanate-propyltriethoxysilane and perfluorooctyltriethoxysilane; The modified pollen was prepared by mixing pretreated pollen and nano zinc oxide, followed by ultrasonic treatment and stirring reaction. The preparation method of the modified lotus leaf wax includes the following steps: Lotus leaf blocks were subjected to ultrasonic soaking and then allowed to stand to obtain lotus leaf wax extract. Modified graphene was obtained by mixing and stirring graphene oxide, octadecylamine, dicyclohexylcarbodiimide and hydroxybenzotriazole. The modified lotus leaf wax was prepared by mixing lotus leaf wax extract, modified graphene, isophorone diisocyanate and dibutyltin dilaurate, followed by ultrasonic treatment and stirring reaction, and then pulverizing.

2. The method for preparing a waterproof fiber composite board as described in claim 1, characterized in that, The weight ratio of the cedar wood fiber, maleic anhydride, benzoyl peroxide, and N,N-dimethylaniline is 100:2~4:0.1~0.2:0.02~0.03; the reaction conditions for mixing and stirring the cedar wood fiber, maleic anhydride, benzoyl peroxide, and N,N-dimethylaniline include a reaction temperature of 65~75℃, a reaction speed of 400 r / min, and a reaction time of 4~6 h.

3. The method for preparing a waterproof fiber composite board as described in claim 1, characterized in that, The weight ratio of defatted pollen, isocyanate-propyltriethoxysilane, and perfluorooctyltriethoxysilane is 100:3~6:15~18; the conditions for mixing and stirring the defatted pollen, isocyanate-propyltriethoxysilane, and perfluorooctyltriethoxysilane include a reaction temperature of 45~55℃, a reaction speed of 600 r / min, and a reaction time of 6~8 h.

4. The method for preparing a waterproof fiber composite board as described in claim 1, characterized in that, The weight ratio of the pretreated pollen to nano zinc oxide is 30:2.5~5.

5.

5. The method for preparing a waterproof fiber composite board as described in claim 1, characterized in that, The weight ratio of graphene oxide, octadecylamine, dicyclohexylcarbodiimide, and hydroxybenzotriazole is 0.2~0.3:0.5~0.7:0.1~0.15:0.1~0.15; the reaction conditions for mixing and stirring graphene oxide, octadecylamine, dicyclohexylcarbodiimide, and hydroxybenzotriazole include a reaction temperature of 75~85℃, a reaction speed of 500 r / min, and a reaction time of 6~8 h; the lotus leaf wax extract and modified graphite... The weight ratio of olefin, isophorone diisocyanate and dibutyltin dilaurate is 20~25:0.6~0.9:1.2~1.5:0.03~0.05; the lotus leaf wax extract, modified graphene, isophorone diisocyanate and dibutyltin dilaurate are mixed and subjected to ultrasonic treatment and stirring reaction conditions, including ultrasonic treatment at 300~350W power for 30~50min, followed by stirring reaction at 800r / min for 4~5h.

6. The method for preparing a waterproof fiber composite board as described in claim 1, characterized in that, The preparation method of the modified aerogel includes the following steps: The modified aerogel is prepared by mixing silica aerogel and isocyanate-based propyltriethoxysilane and stirring at 500 r / min for 4-5 h at 50-60 °C. After filtration and drying, the modified aerogel is obtained. The weight ratio of the silica aerogel to isocyanate-propyltriethoxysilane is 100:8~12.

7. The method for preparing a waterproof fiber composite board as described in claim 1, characterized in that, The weight ratio of the pretreated wood fiber, phenolic resin, modified pollen, modified lotus leaf wax, stannous octoate, and modified aerogel is 100:80~90:20~25:8~12:0.2~0.25:5~8; the hot-pressing conditions include a hot-pressing temperature of 150~170℃, a pressure of 10MPa, and a hot-pressing time of 2~3h.

8. A waterproof fiber composite board, characterized in that, The waterproof fiber composite board is prepared by any one of the preparation methods described in claims 1 to 7.

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