Preparation method of high-wear-resistance wood-plastic composite material

Abstract

The invention discloses a preparation method of a high-wear-resistance wood-plastic composite material, which comprises the following steps: by taking straw as a raw material, modifying the straw through borax, loading the straw with zirconium dioxide at a high temperature, performing cross weaving on the straw and a thermoplastic plastic film to form a laminated assembly, and finally realizing curing and molding of the composite material through a hot press molding technology. According to the invention, the problem of poor interfacial compatibility of straw and thermoplastic polymer is effectively solved through straw treatment, the wettability and adhesiveness of fibers are improved, and the wear resistance of the wood-plastic composite material is further improved by utilizing the self-lubricating property of zirconium dioxide; meanwhile, a new solution is provided for sustainable development through cyclic utilization of straw resources.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to a preparation method of a highly wear-resistant wood-plastic composite material. Background Art

[0002] Wood-plastic composite materials are composite materials prepared from natural wood fibers and plastic matrices through processes such as melt extrusion, hot pressing, and injection molding. Due to their advantages such as low cost, high stiffness, and recyclability, they are widely used in infrastructure, floor walkways, transportation packaging, and other fields. Although wood-plastic composite materials have many excellent properties, their main application in outdoor environments is limited by defects such as low mechanical strength and insufficient wear resistance, restricting their application scope and further industrialization.

[0003] Crop straw has gradually been used as a reinforcing filler for wood-plastic composite materials due to its advantages such as low price, easy availability, and abundant yield. The full utilization of straw resources can not only effectively solve the pollution problem of agricultural waste but also reduce the production cost of wood-plastic composite materials. However, due to the presence of hydrophilic functional groups on the surface of straw fibers, the compatibility with the hydrophobic polymer matrix is poor, thus affecting the performance of the composite material. Through surface treatment, such as chemical modification, physical treatment, or coating, impurities can be removed, surface activity can be increased, and the bonding force between the fiber and the matrix can be improved, enabling the composite material to have better strength, toughness, and wear resistance.

[0004] Zirconia has become an ideal additive for enhancing the performance of composite materials due to its excellent wear resistance, strength, and chemical stability. The loading of zirconia can improve the structural stability of the material, reduce microdamage generated during the wear process, increase the toughness of the composite material, and reduce brittleness. Through uniformly distributed zirconia particles, the composite material can better resist external influences during friction and wear, thereby significantly improving its wear resistance. However, how to effectively disperse zirconia uniformly in the composite material matrix to improve the overall performance of the composite material remains a problem worthy of in-depth discussion.

[0005] The traditional preparation process of wood-plastic composite materials usually includes the mixing and extrusion of each component, often making it difficult to achieve uniform distribution of the internal components of the material, and lacking effective control over the fiber direction and arrangement during the processing, resulting in limited performance of the final material. For this reason, the present invention proposes to adopt a new weaving and blanking and hot pressing forming process to achieve a better laminated structure through cross-weaving between straw and thermoplastic plastic films to ensure tight bonding between different material components. Summary of the Invention

[0006] To solve the above problems, the present invention proposes a preparation method of a highly wear-resistant wood-plastic composite material. By treating straw with borax, loading zirconia, and cross-weaving with a thermoplastic plastic film, a high-performance wood-plastic composite material is finally prepared by hot pressing. This method can not only improve the wear resistance and structural stability of the material, but also make full use of agricultural waste, achieving a double improvement in economic and environmental benefits.

[0007] The specific scheme of this invention patent is as follows: A preparation method of a highly wear-resistant wood-plastic composite material, characterized by including the following steps: S1. Borax treatment: Using straw as raw material, after preliminary cleaning and impurity removal, take 1000 g and soak it in 2000 mL of sodium tetraborate aqueous solution, magnetically stir at room temperature for 3 - 4 hours, and the concentration of the sodium tetraborate solution is 3 - 5 mol / L; Use deionized water to wash the treated straw multiple times until the pH value reaches neutral to obtain borax-treated straw; S2. Zirconia loading: a. Mixing and ball milling: Mix 90% zirconia (ZrO2), 7% - 9% yttrium oxide (Y2O3), and 1% - 3% magnesium oxide (MgO), magnetically stir for 10 - 15 min to ensure that the dry powder is fully and evenly mixed; Take 100 g of the mixed powder and 50 mL of ethanol and place them in a ball mill tank, use alumina beads with a diameter of 5 - 10 mm as the ball milling medium, the ball milling speed is 100 - 300 r / min, and the ball milling time is 2 - 4 hours; After ball milling, take out the slurry and place it in an oven with nitrogen introduced for drying, and the drying temperature is 80 °C until the solvent completely volatilizes to obtain the dried mixed powder; b. Firing the solid solution: Put the mixed powder obtained in a into a crucible and heat it, the firing temperature is 1000 °C, the holding time is 1 - 3 hours, and the heating rate is 5 - 10 °C / min to obtain a uniform Y2O3 - MgO - ZrO2 solid solution; c. Dissolution treatment: Dissolve the Y2O3 - MgO - ZrO2 solid solution obtained in b in 100 - 200 mL of deionized water, add 1 - 10 mL of 0.5 mol / L dilute hydrochloric acid, heat it to 80 °C with an electric furnace and continuously magnetically stir; When the solid solution is dissolved, perform ultrasonic-assisted treatment, the ultrasonic frequency is 20 kHz, and the treatment time is 60 - 90 min; After ultrasonic treatment, use a high-speed centrifuge to centrifuge the solution at a speed of 5000 rpm for 10 - 15 min to obtain a Y2O3 - MgO - ZrO2 precipitate; d. Precipitate drying: Dry the Y2O3 - MgO - ZrO2 precipitate obtained in c at 80 °C to obtain high-purity Y2O3 - MgO - ZrO2 powder; e. Suspension preparation: Dissolve the high-purity Y2O3-MgO-ZrO2 powder obtained in d in 100 - 200 mL of ethanol, and homogenize it for 10 - 15 min under a pressure of 30 MPa using a high-pressure homogenizer to obtain a uniform zirconia suspension; f. Gel preparation: Mix the zirconia suspension obtained in e with a 5% polyvinyl alcohol solution in a mass ratio of 1:1, and homogenize it again for 10 - 15 min under a pressure of 30 MPa using a high-pressure homogenizer to obtain the zirconia gel; g. Cut the straw obtained in S1 into slender strips with a width of 1 - 1.5 mm, evenly immerse them in the zirconia gel heated to 60 - 80 °C, continuously stir magnetically, and the impregnation time is 3 - 4 hours to obtain straw loaded with zirconia; S3. Weaving and laminating: Cross-weave the straw loaded with zirconia obtained in S2 with a thermoplastic plastic film to obtain a straw / film laminated blank; S4. Hot pressing and forming: Use the thermoplastic plastic film as the upper and lower layers, organize the straw / film lamination and impregnate the material by the film stacking method, and place it in a flat vulcanizing machine for hot pressing and forming.

[0008] Further, the straw is at least one of rape straw, rice straw, and corn straw.

[0009] Further, the thermoplastic plastic film is at least one of polyvinyl chloride (PVC), polyethylene (PE), and polypropylene (PP) films.

[0010] Further, place a straw loaded with zirconia every 3 - 5 mm on a thermoplastic plastic film with dimensions of 170 mm × 110 mm × 1 mm, and cross-weave them with the fiber direction laying at 0° - 90° to obtain a straw / film laminated blank.

[0011] Further, the preparation method of a high wear-resistant wood-plastic composite material includes the following steps: a. Preheating: First, heat the flat vulcanizing machine to 90 - 100 °C, then send the unidirectional straw / film laminated impregnated material with 10 - 14 layers into the hot press, and heat it to 170 - 180 °C in the zero-pressure closing state; b. Hot pressing: Under a pressure of 1 - 2 MPa, keep the temperature and pressure for 20 - 30 min to ensure that the polymer matrix in the impregnated material fully impregnates the fibers; c. Cooling: Cool the flat vulcanizing machine in the pressure-holding state through a water cooling system, and take out the composite material after the temperature drops to room temperature.

[0012] Further, cut the specimens according to the dimensions required by the wood-plastic composite material performance test standard.

[0013] Working principle of the present invention: Borax, as a polybasic acid salt, can promote the formation of cross-linked structures between polyhydroxy compounds in straw. This cross-linking effect improves the overall strength and toughness of the material, thereby enhancing the bonding effect between straw and the polymer matrix.

[0014] During the preparation process of zirconia gel, wet ball milling mixing is used to reduce the electrostatic interaction and adhesion force between zirconia, yttrium oxide, and magnesium oxide, thereby reducing the agglomeration phenomenon of particles and obtaining a more uniform particle distribution. Adding yttrium oxide is to stabilize the cubic crystal structure of zirconia, prevent its phase transformation, thereby improving its thermal stability and strength. Magnesium oxide is used as a cosolvent in this invention patent to lower the sintering temperature of zirconia and improve the sintering characteristics of zirconia. During the dissolution process, chemical reactions and physical separation are involved. Ultrasonic-assisted treatment is used to promote the uniform transfer of heat in the material, enhance the effective heat treatment effect, and help obtain a higher-purity precipitate. Under high-temperature impregnation of straw, the molecular movement speed in zirconia gel increases, and zirconia is more likely to penetrate and infiltrate into the microstructure of straw, achieving a more uniform loading. In addition, high temperature may also promote cross-linking or chemical reactions between zirconia and straw, forming a more stable composite structure.

[0015] Combining straw with a thermoplastic film through cross-weaving to form a laminated structure increases the overall strength and structural stability of the material. During use, the fiber direction of the straw can better disperse external stress, reduce local wear and fatigue, thereby improving the wear resistance. Thermocompression molding makes the material fully fuse through high temperature and pressure to form a dense composite. This process not only helps to evenly distribute each component but also enables the polymer matrix to better penetrate the fibers, improving the density of the composite material and reducing the possibility of material spalling and crack formation during the wear process.

[0016] Compared with the prior art, the present invention uses weakly alkaline borax to treat straw, reducing the damage to the performance of straw itself by alkali treatment; improving the purity and dispersibility of zirconia through heat treatment, ultrasonic treatment, high-pressure homogenization, etc., which is beneficial to form uniformly loaded zirconia on straw in combination with straw. At the same time, a better laminated structure is achieved through weaving blanking, cross-weaving, and thermocompression molding to ensure the tight combination between different materials. Brief description of the drawings

[0017] Figure 1 are the test results of the mechanical and wear resistance performance of Examples 1-3 and Comparative Examples 1-3; Figure 2 is the surface morphology diagram of the straw after treatment in Example 1; Figure 3 is the surface morphology diagram of the straw after treatment in Comparative Example 3. Detailed implementation manners

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0019] For those not specifying specific test steps or conditions in the embodiments, operations or conditions of conventional test steps described in the literature in this field can be followed. For reagents or instruments without indicating the manufacturer, conventional reagent products available in the market can be used. Example 1

[0020] A highly wear-resistant wood-plastic composite material is prepared according to the following method, and the steps are as follows: S1. Borax treatment: Taking rapeseed straw as the raw material, after preliminary cleaning and impurity removal, 1000 g is taken and soaked in 2000 mL of sodium tetraborate aqueous solution, magnetically stirred at room temperature for 3 hours, and the concentration of the sodium tetraborate solution is 3%; the treated straw is rinsed repeatedly with deionized water until the pH value reaches neutral to obtain borax-treated rapeseed straw; S2. Zirconia loading: a. Mixing and ball milling: Mix 90% zirconia (ZrO2), 7% yttrium oxide (Y2O3), and 3% magnesium oxide (MgO), and magnetically stir for 10 min; take 100 g of the mixed powder and 50 mL of ethanol and place them in a ball milling tank, use alumina beads with a diameter of 5 mm as the ball milling medium, the ball milling speed is 200 r / min, and the ball milling time is 3 hours; after the ball milling is completed, take out the slurry and place it in an oven with nitrogen introduced for drying, and the drying temperature is 80 °C until the solvent completely volatilizes to obtain a dried mixed powder; b. Firing the solid solution: Put the mixed powder obtained in a into a crucible and heat it, the firing temperature is 1000 °C, the heat preservation time is 2 hours, and the heating rate is 10 °C / min to obtain a uniform Y2O3-MgO-ZrO2 solid solution; c. Dissolution treatment: Dissolve the Y2O3-MgO-ZrO2 solid solution obtained in b in 150 mL of deionized water, and add 5 mL of 0.5 mol / L dilute hydrochloric acid to improve the solubility. While heating to 80 °C with an electric furnace, magnetically stir; during the dissolution of the solid solution, perform ultrasonic-assisted treatment, the ultrasonic frequency is 20 kHz, and the treatment time is 60 min; after the ultrasonic treatment, use a high-speed centrifuge to centrifuge the solution at a speed of 5000 rpm for 15 min to obtain a Y2O3-MgO-ZrO2 precipitate; d. Precipitate drying: The Y2O3-MgO-ZrO2 precipitate obtained in c is dried at 80 °C to obtain high-purity Y2O3-MgO-ZrO2 powder; e. Suspension preparation: The high-purity Y2O3-MgO-ZrO2 powder obtained in d is dissolved in 150 mL of ethanol and homogenized using a high-pressure homogenizer at a pressure of 30 MPa for 10 min to obtain a uniform zirconia suspension; f. Gel preparation: The zirconia suspension obtained in e is mixed with a 5% polyvinyl alcohol solution at a mass ratio of 1:1 and homogenized using a high-pressure homogenizer at a pressure of 30 MPa for 10 min to obtain a zirconia gel; g. The rape straw obtained in S1 is cut into slender strips with a width of 1.5 mm and uniformly immersed in the zirconia gel heated to 80 °C, and continuously magnetically stirred for 3 hours to obtain rape straw loaded with zirconia; S3. Weaving and laminating: One piece of the zirconia-loaded straw obtained in S2 is placed every 5 mm on a thermoplastic film with dimensions of 170 mm × 110 mm × 1 mm and cross-woven with the film, with the fiber direction laid at 0°, to obtain a straw / film laminated blank; S4. Material forming: a. Preheating: The flat vulcanizing machine is first heated to 100 °C, and then the impregnated material obtained by laminating 12 layers of unidirectional rape straw / film is sent into the hot press and heated to 175 °C in the zero-pressure closing state; b. Hot pressing: Under a pressure of 1 MPa, keep the temperature and pressure for 30 min to ensure that the polymer matrix in the post-impregnated material fully impregnates the fibers; c. Cooling: The flat vulcanizing machine is cooled through a water cooling system in the pressure-holding state, and the composite material is taken out after the temperature drops to room temperature. Example 2

[0021] A highly wear-resistant wood-plastic composite material is prepared according to the following method, and the steps are as follows: S1. Borax treatment: Using rice straw as raw material, after preliminary cleaning and impurity removal, 1000 g is taken and soaked in 2000 mL of sodium decaborate aqueous solution, and magnetically stirred at room temperature for 3 hours, where the concentration of the sodium decaborate solution is 3%; the treated straw is rinsed repeatedly with deionized water until the pH value reaches neutral to obtain borax-treated rice straw; S2. Zirconia loading: a. Hybrid ball milling: Mix 90% zirconia (ZrO2), 7% yttrium oxide (Y2O3), and 3% magnesium oxide (MgO), and perform electromagnetic stirring for 10 min. Take 100 g of the mixed powder and 50 mL of ethanol and place them in a ball mill jar. Use alumina beads with a diameter of 5 mm as the ball milling medium. The ball milling speed is 200 r / min, and the ball milling time is 3 hours. After ball milling, take out the slurry and place it in an oven with nitrogen introduced for drying. The drying temperature is 80 °C until the solvent completely evaporates to obtain the dried mixed powder; b. Firing the solid solution: Put the mixed powder obtained in a into a crucible and heat it. The firing temperature is 1000 °C, the holding time is 2 hours, and the heating rate is 10 °C / min to obtain a uniform Y2O3-MgO-ZrO2 solid solution; c. Dissolution treatment: Dissolve the Y2O3-MgO-ZrO2 solid solution obtained in b in 150 mL of deionized water, and add 5 mL of 0.5 mol / L dilute hydrochloric acid to increase the solubility. While heating to 80 °C using an electric furnace, perform electromagnetic stirring. When the solid solution is dissolved, perform ultrasonic-assisted treatment. The ultrasonic frequency is 20 kHz, and the treatment time is 60 min. After ultrasonic treatment, use a high-speed centrifuge to centrifuge the solution at a speed of 5000 rpm for 15 min to obtain Y2O3-MgO-ZrO2 precipitate; d. Drying the precipitate: Dry the Y2O3-MgO-ZrO2 precipitate obtained in c at 80 °C to obtain high-purity Y2O3-MgO-ZrO2 powder; e. Preparation of suspension: Dissolve the high-purity Y2O3-MgO-ZrO2 powder obtained in d in 150 mL of ethanol, and homogenize it for 10 min at a pressure of 30 MPa using a high-pressure homogenizer to obtain a uniform zirconia suspension; f. Gel preparation: Mix the zirconia suspension obtained in e with a 5% polyvinyl alcohol solution in a mass ratio of 1:1, and homogenize it again for 10 min at a pressure of 30 MPa using a high-pressure homogenizer to obtain zirconia gel; g. Cut the rice straw obtained in S1 into slender strips with a width of 1.5 mm, and uniformly immerse them in the zirconia gel heated to 80 °C, and continuously perform electromagnetic stirring. The impregnation time is 3 hours to obtain rice straw loaded with zirconia; S3. Weaving and assembling: Place a rice straw loaded with zirconia obtained in S2 every 5 mm on a thermoplastic film with dimensions of 170 mm × 110 mm × 1 mm, and cross-weave it with the film. The fiber direction is laid at 0°, and a straw / film laminated assembly is obtained; S4. Material forming: a. Preheating: The flat vulcanizer is first heated to 100 °C, and then the 12-layer unidirectional rice straw / film laminated impregnated material is fed into the hot press. It is heated to 175 °C in the state of zero-pressure closing. b. Hot pressing: Under a pressure of 1 MPa, keep the temperature and pressure constant for 30 min to ensure that the polymer matrix in the post-impregnated material fully impregnates the fibers. c. Cooling: The flat vulcanizer is cooled through the water cooling system in the state of constant pressure, and the composite material is taken out after the temperature drops to room temperature. Example 3

[0022] A highly wear-resistant wood-plastic composite material is prepared according to the following method. The steps are as follows: S1. Borax treatment: Taking corn straw as the raw material, after preliminary cleaning and impurity removal, 1000 g is taken and soaked in 2000 mL of sodium decaborate aqueous solution. It is magnetically stirred at room temperature for 3 hours, and the concentration of the sodium decaborate solution is 3%; the treated straw is rinsed repeatedly with deionized water until the pH value reaches neutral to obtain borax-treated corn straw. S2. Zirconia loading: a. Mixing and ball milling: Mix 90% zirconia (ZrO2), 7% yttrium oxide (Y2O3), and 3% magnesium oxide (MgO), and magnetically stir for 10 min; take 100 g of the mixed powder and 50 mL of ethanol and place them in a ball milling tank. Use alumina beads with a diameter of 5 mm as the ball milling medium, the ball milling speed is 200 r / min, and the ball milling time is 3 hours; after the ball milling is completed, take out the slurry and place it in an oven with nitrogen introduced for drying. The drying temperature is 80 °C until the solvent completely volatilizes to obtain a dried mixed powder. b. Firing the solid solution: Put the mixed powder obtained in a into a crucible and heat it. The firing temperature is 1000 °C, the holding time is 2 hours, and the heating rate is 10 °C / min to obtain a uniform Y2O3-MgO-ZrO2 solid solution. c. Dissolution treatment: Dissolve the Y2O3-MgO-ZrO2 solid solution obtained in b in 150 mL of deionized water, and add 5 mL of 0.5 mol / L dilute hydrochloric acid to increase the solubility. While heating to 80 °C with an electric furnace, magnetically stir; when the solid solution is dissolved, perform ultrasonic-assisted treatment, the ultrasonic frequency is 20 kHz, and the treatment time is 60 min; after the ultrasonic treatment, use a high-speed centrifuge to centrifuge the solution at a speed of 5000 rpm for 15 min to obtain a Y2O3-MgO-ZrO2 precipitate. d. Drying the precipitate: Dry the Y2O3-MgO-ZrO2 precipitate obtained in c at 80 °C to obtain high-purity Y2O3-MgO-ZrO2 powder. e. Suspension preparation: Dissolve the high-purity Y2O3-MgO-ZrO2 powder obtained in d in 150 mL of ethanol, and homogenize it for 10 min at a pressure of 30 MPa using a high-pressure homogenizer to obtain a uniform zirconia suspension; f. Gel preparation: Mix the zirconia suspension obtained in e with a 5% polyvinyl alcohol solution in a mass ratio of 1:1, and homogenize it again for 10 min at a pressure of 30 MPa using a high-pressure homogenizer to obtain a zirconia gel; g. Cut the corn straw obtained in S1 into slender strips with a width of 1.5 mm, uniformly immerse them in the zirconia gel heated to 80 °C, continuously stir magnetically, and the impregnation time is 3 hours to obtain corn straw loaded with zirconia; S3. Weaving and assembling: Place a piece of the zirconia-loaded straw obtained in S2 every 5 mm on a thermoplastic film with dimensions of 170 mm × 110 mm × 1 mm, and cross-weave it with the film, with the fiber direction laid at 0°, to obtain a straw / film laminated assembly; S4. Material forming: a. Preheating: The flat vulcanizing machine first heats up to 100 °C, then sends 12 layers of unidirectional corn straw / film laminated impregnated materials into the hot press, and heats up to 175 °C in the state of closing at 0 pressure; b. Hot pressing: Under a pressure of 1 MPa, keep the temperature and pressure for 30 min to ensure that the polymer matrix in the post-impregnated material fully impregnates the fibers; c. Cooling: The flat vulcanizing machine is cooled through a water cooling system in the pressure-holding state, and the composite material is taken out after the temperature drops to room temperature.

[0023] Comparative Example 1 S1. Borax treatment: Using rapeseed straw as raw material, after preliminary cleaning and impurity removal, take 1000 g and soak it in 2000 mL of sodium decaborate aqueous solution, stir magnetically at room temperature for 3 hours, where the concentration of the sodium decaborate solution is 3%; rinse the treated straw with deionized water multiple times until the pH value reaches neutral to obtain borax-treated rapeseed straw; S2. Weaving and assembling: Cut the rapeseed straw obtained in S1 into slender strips with a width of 1.5 mm and a thickness of 0.5 mm, place one every 5 mm on a thermoplastic film with dimensions of 170 mm × 110 mm × 1 mm, and cross-weave it with the film, with the fiber direction laid at 0°, to obtain a straw / film laminated assembly; S3. Material forming: a. Preheating: The flat vulcanizer is first heated to 100 °C, and then the 12-layer unidirectional rapeseed straw / film laminated impregnated material is fed into the hot press. It is heated to 175 °C under the closed state of 0 pressure. b. Hot pressing: Under a pressure of 1 MPa, keep the temperature and pressure constant for 30 min to ensure that the polymer matrix in the post-impregnated material fully impregnates the fibers. c. Cooling: The flat vulcanizer is cooled through the water cooling system under the pressure-holding state, and the composite material is taken out after the temperature drops to room temperature.

[0024] Comparative Example 2 S1. Zirconia loading: a. Mixing and ball milling: Mix 90% zirconia (ZrO2), 7% yttrium oxide (Y2O3), and 3% magnesium oxide (MgO), and stir magnetically for 10 min. Take 100 g of the mixed powder and 50 mL of ethanol and place them in a ball mill jar. Use alumina beads with a diameter of 5 mm as the ball milling medium. The ball milling speed is 200 r / min, and the ball milling time is 3 hours. After the ball milling is completed, take out the slurry and place it in an oven with nitrogen introduced for drying. The drying temperature is 80 °C until the solvent completely evaporates to obtain the dried mixed powder. b. Firing the solid solution: Put the mixed powder obtained in a into a crucible and heat it. The firing temperature is 1000 °C, the holding time is 2 hours, and the heating rate is 10 °C / min to obtain a uniform Y2O3-MgO-ZrO2 solid solution. c. Dissolution treatment: Dissolve the Y2O3-MgO-ZrO2 solid solution obtained in b in 150 mL of deionized water, and add 5 mL of 0.5 mol / L dilute hydrochloric acid to increase the solubility. While heating to 80 °C with an electric furnace, stir magnetically. When the solid solution is dissolved, perform ultrasonic-assisted treatment with an ultrasonic frequency of 20 kHz and a treatment time of 60 min. After the ultrasonic treatment, use a high-speed centrifuge to centrifuge the solution at a speed of 5000 rpm for 15 min to obtain the Y2O3-MgO-ZrO2 precipitate. d. Drying the precipitate: Dry the Y2O3-MgO-ZrO2 precipitate obtained in c at 80 °C to obtain high-purity Y2O3-MgO-ZrO2 powder. e. Preparation of the suspension: Dissolve the high-purity Y2O3-MgO-ZrO2 powder obtained in d in 150 mL of ethanol, and homogenize it at a pressure of 30 MPa for 10 min using a high-pressure homogenizer to obtain a uniform zirconia suspension. f. Gel preparation: Mix the zirconia suspension obtained in e with a 5% polyvinyl alcohol solution in a mass ratio of 1:1, and homogenize it again at a pressure of 30 MPa for 10 min using a high-pressure homogenizer to obtain a zirconia gel. g. Cut the rapeseed straw after cleaning and impurity removal into slender strips with a width of 1.5 mm and a thickness of 0.5 mm, evenly immerse them in zirconia gel heated to 80 °C, continuously stir magnetically, and the impregnation time is 3 - 6 hours to obtain rapeseed straw loaded with zirconia; S2. Weaving and blank forming: Weave the rapeseed straw obtained in S1 and a PVC film with dimensions of 170 mm × 110 mm × 1 mm crosswise every 5 mm, with the fiber direction laid parallel at 0°, to obtain a rapeseed straw / PVC film laminated blank; S3. Material forming: a. Preheating: The flat vulcanizing machine first heats up to 100 °C, then feeds the impregnated material after laminating 12 layers of unidirectional rapeseed straw / film into the hot press, and heats up to 175 °C in the state of zero-pressure closing; b. Hot pressing: Under a pressure of 1 MPa, keep the temperature and pressure for 30 min to ensure that the polymer matrix in the impregnated material fully impregnates the fibers; c. Cooling: The flat vulcanizing machine is cooled through the water cooling system in the pressure-holding state, and the composite material is taken out after the temperature drops to room temperature.

[0025] Comparative Example 3 S1. Weaving and blank forming: Cut the rapeseed straw after cleaning and impurity removal into slender strips with a width of 1.5 mm and a thickness of 0.5 mm, place one every 5 mm on a thermoplastic plastic film with dimensions of 170 mm × 110 mm × 1 mm, and cross-weave it with the film, with the fiber direction laid at 0°, to obtain a straw / film laminated blank; S2. Material forming: a. Preheating: The flat vulcanizing machine first heats up to 100 °C, then feeds the impregnated material after laminating 12 layers of unidirectional rapeseed straw / film into the hot press, and heats up to 175 °C in the state of zero-pressure closing; b. Hot pressing: Under a pressure of 1 MPa, keep the temperature and pressure for 30 min to ensure that the polymer matrix in the impregnated material fully impregnates the fibers; c. Cooling: The flat vulcanizing machine is cooled through the water cooling system in the pressure-holding state, and the composite material is taken out after the temperature drops to room temperature.

[0026] Verify the performance of the composite materials in the above examples and comparative examples as follows: Tensile property test Refer to the GB / T1040.1 - 2006 standard, use an E43.104 type microcomputer-controlled electronic universal testing machine to test the tensile strength of the composite material, the tensile rate is 2 mm / min, and the specimen size is 160 mm × 10 mm × 4 mm.

[0027] Flexural property test Referring to the GB / T9341-2008 standard, an E43.104 type microcomputer-controlled electronic universal testing machine was used to test the flexural strength of the composite material. The loading rate was 2 mm / min, the span was 64 mm, and the specimen size was 80 mm×10 mm×4 mm.

[0028] Impact property test Referring to the GB / T1043.1-2008 standard, a G-P01 type cantilever simple beam impact testing machine was used to test the impact strength of the composite material. The pendulum energy was 2 J, and the specimen size was 80 mm×10 mm×4 mm.

[0029] Wear property test Referring to the ASTM-G65-16 (2021) standard, an MLG-130 type dry sand rubber wheel abrasive wear testing machine was used to test the abrasive wear resistance of the composite material. Among them, the test abrasive was 0.5 mm dry sand, the hardness of the rubber wheel was 60 (Shore hardness), the diameter was 228.6 mm, the rotation speed was 150 r / min, the applied load was 45 N, and the wear time was 20 min. The surface of the specimen was cleaned with anhydrous ethanol and air-dried before and after the test, and the average value of 5 test data was taken. The specific wear rate ( W S ) The calculation formula is as follows: Where: m1 is the weight before wear, mg; m2 is the weight after wear, mg; L is the sliding distance, m; F is the applied load, N; ρ is the specimen density, g / cm 3 .

[0030] Conclusion: As Figure 1 shown, the tensile, flexural, and impact strengths of the wood-plastic composite material provided in Example 1 are significantly improved compared with those of the wood-plastic composite materials provided in Comparative Example 1 and Comparative Example 2. This shows that the composite materials prepared by treating straw with borax and coupling with zirconia are all better in performance than the wood-plastic composite materials treated singly. From the test results of tensile, flexural, impact, and abrasive wear properties of Example 1 and Comparative Example 3, it can be seen that the method of the present invention can increase the tensile, flexural, and impact strengths of the wood-plastic composite material by 73.8%, 67%, and 32.97% respectively, and the specific wear rate is reduced by 15.94%.

[0031] As Figure 2 、 3 shown are the surface morphology diagrams of the straws processed in Example 1 and Comparative Example 3. As Figure 2 shown, the surface of the straw is relatively rough, with relatively regular and dense particulate matter adhering thereto, which helps to enhance the bonding force between the straw and the polymer matrix. In addition, zirconia, as a loading material, can form a friction protection layer during the wear process to reduce the direct wear of the polymer. Moreover, due to its high hardness, the zirconia particles play a role in bearing the wear impact and dispersing the wear energy in three-body abrasive wear, thereby improving the wear resistance of the composite material. However, the surface of the untreated straw is relatively smooth and uniform, with a relatively flat surface structure and fewer particulate matters, resulting in insufficient interfacial bonding force between the straw and the matrix, and causing the material to easily fall off during the wear process, thereby reducing the overall wear resistance of the composite material.

[0032] The above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those skilled in the art, various modifications and changes can be made to this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A preparation method of a highly wear-resistant wood-plastic composite material, characterized in that, It includes the following steps: S1. Borax treatment: Using straw as raw material, after preliminary cleaning and impurity removal, take 1000 g and soak it in 2000 mL of sodium decaborate aqueous solution. Stir magnetically at room temperature for 3 - 4 hours. The concentration of the sodium decaborate solution is 3 - 5 mol / L; rinse the treated straw with deionized water multiple times until the pH value reaches neutral to obtain borax-treated straw; S2. Zirconia loading: a. Mixing and ball milling: Mix 90% zirconia (ZrO2), 7% - 9% yttrium oxide (Y2O3), and 1% - 3% magnesium oxide (MgO), stir magnetically for 10 - 15 min to ensure thorough and uniform mixing of the dry powder; take 100 g of the mixed powder and 50 mL of ethanol and place them in a ball milling jar. Use alumina beads with a diameter of 5 - 10 mm as the ball milling medium. The ball milling speed is 100 - 300 r / min, and the ball milling time is 2 - 4 hours; after ball milling, take out the slurry and place it in an oven with nitrogen introduced for drying. The drying temperature is 80 °C until the solvent completely evaporates to obtain the dried mixed powder; b. Firing the solid solution: Put the mixed powder obtained in a into a crucible and heat it. The firing temperature is 1000 °C, the holding time is 1 - 3 hours, and the heating rate is 5 - 10 °C / min to obtain a uniform Y2O3 - MgO - ZrO2 solid solution; c. Dissolution treatment: Dissolve the Y2O3 - MgO - ZrO2 solid solution obtained in b in 100 - 200 mL of deionized water, add 1 - 10 mL of 0.5 mol / L dilute hydrochloric acid, heat with an electric furnace to 80 °C and continuously stir magnetically; during the dissolution of the solid solution, perform ultrasonic-assisted treatment. The ultrasonic frequency is 20 kHz, and the treatment time is 60 - 90 min; after ultrasonic treatment, use a high-speed centrifuge to centrifuge the solution at a speed of 5000 rpm for 10 - 15 min to obtain Y2O3 - MgO - ZrO2 precipitate; d. Drying the precipitate: Dry the Y2O3 - MgO - ZrO2 precipitate obtained in c at 80 °C to obtain high-purity Y2O3 - MgO - ZrO2 powder; e. Preparation of suspension: Dissolve the high-purity Y2O3 - MgO - ZrO2 powder obtained in d in 100 - 200 mL of ethanol, and homogenize it with a high-pressure homogenizer at a pressure of 30 MPa for 10 - 15 min to obtain a uniform zirconia suspension; f. Gel preparation: Mix the zirconia suspension obtained in e with a 5% polyvinyl alcohol solution in a mass ratio of 1:1, and homogenize it again with a high-pressure homogenizer at a pressure of 30 MPa for 10 - 15 min to obtain zirconia gel; g. Cut the straw obtained in S1 into slender strips with a width of 1 - 1.5 mm, evenly immerse them in the zirconia gel heated to 60 - 80 °C, continuously stir magnetically, and the impregnation time is 3 - 4 hours to obtain straw loaded with zirconia; S3. Weaving and assembling: Cross-weave the zirconia-loaded straw obtained in S2 with a thermoplastic plastic film to obtain a straw / film laminated assembly; S4. Hot pressing forming: Using thermoplastic plastic film as the upper and lower layers, the straw / film laminated pre-impregnated material is organized by the film stacking method, and then placed in a flat vulcanizing machine for hot pressing forming.

2. The preparation method of a highly wear-resistant wood-plastic composite material according to claim 1, characterized in that The straw is at least one of rape straw, rice straw, and corn straw.

3. The preparation method of a highly wear-resistant wood-plastic composite material according to claim 1, characterized in that The thermoplastic plastic film is one of polyvinyl chloride (PVC), polyethylene (PE), and polypropylene (PP) films.

4. The preparation method of a highly wear-resistant wood-plastic composite material according to claim 1, characterized in that The method for weaving and assembling the blank is as follows: Place the zirconia-loaded straw on the thermoplastic plastic film with a size of 170 mm×110 mm×1 mm every 3-5 mm, and cross-weave it with the film. The fiber direction is laid at 0°-90° to obtain the straw / film laminated blank.

5. The preparation method of a highly wear-resistant wood-plastic composite material according to claim 1, characterized in that The steps of the hot pressing forming are as follows: a. Preheating: The flat vulcanizing machine first heats up to 90-100 °C, then sends the unidirectional straw / film laminated pre-impregnated material with 10-14 layers into the hot press, and heats up to 170-180 °C in the state of zero-pressure closing. b. Hot pressing: Under the pressure of 1-2 MPa, keep the temperature and pressure for 20-30 min to ensure that the polymer matrix in the pre-impregnated material fully impregnates the fibers. c. Cooling: The flat vulcanizing machine is cooled through the water cooling system in the state of holding pressure, and taken out after the temperature drops to room temperature.

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