Modified wood-plastic composite material for retired fan blade powder and preparation method of modified wood-plastic composite material

Abstract

The invention discloses an ex-service fan blade powder modified wood-plastic composite material and a preparation method thereof, and belongs to the technical field of solid waste recovery and composite materials, the modified wood-plastic composite material comprises the following components: plant fiber powder, thermoplastic plastic, pretreated ex-service fan blade powder, an interface compatilizer and an auxiliary additive; the pretreatment method of the retired fan blade powder comprises the step of carrying out surface modification through a silane coupling agent. According to the invention, the retired fan blade which is difficult to treat is converted into the wood-plastic composite material filler with high additional value, so that the purpose of treating waste with waste is realized, the environmental protection pain point of the wind power industry and the plastic / wood processing industry is solved, and the circular economy concept is met. Compared with a traditional wood-plastic composite material, the modified wood-plastic composite material has higher bending strength and bending modulus, lower water absorption and linear thermal expansion coefficient and better creep resistance and ultraviolet aging resistance, and is particularly suitable for outdoor scenes with higher requirements for structural strength and durability.

Description

Technical Field

[0001] This invention relates to the field of solid waste recycling and composite material technology, specifically to a wood-plastic composite material modified from decommissioned wind turbine blade powder and its preparation method. Background Technology

[0002] Wood-plastic composites (WPCs) are widely used due to their environmental friendliness and corrosion resistance. However, traditional WPCs have the following inherent defects: 1. Insufficient mechanical properties: Poor interfacial compatibility between plant fibers and the plastic matrix leads to low material toughness and impact strength; 2. Poor weather resistance: Plant fibers are prone to moisture absorption, resulting in dimensional instability and mold growth, and the plastic matrix is ​​susceptible to UV aging; 3. Poor creep performance: They are prone to deformation under long-term loads.

[0003] On the other hand, with the booming development of the wind power industry, early-installed wind turbines are facing a large-scale decommissioning wave. Wind turbine blades are mainly composed of thermosetting composite materials such as glass fiber reinforced polymer (GFRP) and epoxy resin, which are chemically stable and extremely difficult to degrade naturally. Currently, the main disposal methods are landfilling or simple crushing followed by co-processing in low-value cement kilns, which not only wastes resources but also brings enormous environmental pressure.

[0004] While there are precedents for using glass fiber to reinforce plastics in existing technologies, directly using recycled wind turbine blade powder (RBP) to modify WPC faces the following significant challenges: 1. Extremely poor interfacial compatibility: RBP is a mixture of inert inorganic glass fiber and cross-linked epoxy resin, which is difficult to bond with polar plant fibers and non-polar plastic matrices. Direct filling will lead to a severe decline in the performance of the composite material. 2. Deterioration of processing fluidity: RBP has irregular shapes and low aspect ratios. Large-scale filling will severely impair melt fluidity, leading to processing difficulties. 3. Uncontrollable performance: RBP has complex sources and large compositional fluctuations. Without effective pretreatment and formulation design, performance improvement cannot be achieved; instead, it becomes an impurity.

[0005] Therefore, developing a method that can effectively utilize RBP and overcome its compatibility issues with the WPC system to ultimately prepare high-performance composite materials has significant environmental and economic value. Summary of the Invention

[0006] The purpose of this invention is to provide a wood-plastic composite material modified with powder from decommissioned wind turbine blades to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] A wood-plastic composite material modified from decommissioned wind turbine blade powder comprises the following components by weight: 20-40 parts plant fiber powder, 30-50 parts thermoplastic plastic, 15-35 parts pretreated decommissioned wind turbine blade powder, 3-8 parts interface compatibilizer, and 1.5-5 parts auxiliary additives; the pretreatment method for the decommissioned wind turbine blade powder is: surface modification by silane coupling agent.

[0009] Furthermore, the pretreatment method for the decommissioned wind turbine blade powder specifically includes the following steps:

[0010] After heat treatment at 80-110℃, the decommissioned wind turbine blade powder is then surface-wetted in an ethanol aqueous solution containing acid anhydride compounds and silane coupling agents, and then dried to obtain pretreated decommissioned wind turbine blade powder.

[0011] Furthermore, in the ethanol-water solution containing the acid anhydride compound and the silane coupling agent, the mass percentage concentration of the acid anhydride compound is 2%-5%, and the mass percentage concentration of the silane coupling agent is 1%-3%.

[0012] Furthermore, the particle size of the decommissioned wind turbine blade powder is 80-400 mesh.

[0013] Furthermore, the acid anhydride compound is [3-(trimethoxysilyl)propyl]succinic anhydride.

[0014] Furthermore, the thermoplastic is one or more of polyethylene, polypropylene, and polyvinyl chloride; the plant fiber powder is one or more of wood powder, bamboo powder, and rice husk powder.

[0015] Furthermore, the interface compatibilizer includes maleic anhydride-grafted polyolefins and epoxy functional group polymers.

[0016] Furthermore, the maleic anhydride-grafted polyolefin is maleic anhydride-grafted polyethylene or maleic anhydride-grafted polypropylene; the epoxy functional group polymer is ethylene-acrylate-glycidyl methacrylate.

[0017] Furthermore, the auxiliary additives include one or more of lubricants, antioxidants, and light stabilizers.

[0018] Another object of the present invention is to provide a method for preparing the above-mentioned decommissioned wind turbine blade powder modified wood-plastic composite material, which includes the following steps:

[0019] Weigh out the plant fiber powder, thermoplastic plastic, pretreated decommissioned wind turbine blade powder, interface compatibilizer, and auxiliary additives according to the weight proportions of the above components.

[0020] Plant fiber powder, thermoplastic plastic, pretreated decommissioned wind turbine blade powder, interface compatibilizer, and auxiliary additives are heated and mixed to obtain a premix.

[0021] The premixed material is melt-blended, extruded, cooled, and pelletized to obtain a modified wood-plastic composite material.

[0022] This invention provides a modified wood-plastic composite material from decommissioned wind turbine blade powder, transforming difficult-to-process decommissioned wind turbine blades into high-value-added wood-plastic composite filler. This achieves waste-to-waste treatment, addressing environmental challenges in both the wind power and plastics / wood processing industries, and aligns with the concept of a circular economy. Specifically, the glass fiber in the decommissioned wind turbine blade powder acts as a rigid reinforcement, significantly improving the strength, modulus, hardness, and heat resistance (heat distortion temperature) of the wood-plastic composite. The cross-linked structure of the epoxy resin in the decommissioned wind turbine blade powder acts as organic rigid particles in the wood-plastic composite, inducing streaks and shear bands to absorb impact energy. This complements the brittleness of the plant fiber powder, improving rigidity while maintaining or improving the impact toughness of the wood-plastic composite to a certain extent. Furthermore, this invention pre-treats the decommissioned wind turbine blade powder using a silane coupling agent and introduces a multi-component interfacial compatibilizer system, constructing a robust "bridge" between the decommissioned wind turbine blade powder and thermoplastics, and between the plant fiber powder and thermoplastics. This solves the core problem of multiphase interfacial compatibility, ensuring effective stress transfer and avoiding performance shortcomings.

[0023] The modified wood-plastic composite material prepared by this invention has higher flexural strength and flexural modulus, lower water absorption and linear thermal expansion coefficient, as well as better creep resistance and UV aging resistance compared with traditional wood-plastic composite materials. It is particularly suitable for outdoor scenarios with higher requirements for structural strength and durability, such as load-bearing flooring, guardrails, and building formwork. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In one embodiment of the present invention, a wood-plastic composite material modified with decommissioned wind turbine blade powder is provided, the preparation method of which includes the following steps:

[0026] S1. After heat-treating the decommissioned wind turbine blade powder at 80-110℃ for 4-6 hours, it is then placed in an ethanol-water solution containing anhydride compounds and silane coupling agents, continuously stirred, and heated to 40-60℃ for surface wetting treatment for 1-3 hours. Finally, it is dried at 80-100℃ to obtain the pretreated decommissioned wind turbine blade powder.

[0027] S2. By weight, add 20-40 parts of plant fiber powder, 30-50 parts of thermoplastic plastic, 15-35 parts of the pretreated retired wind turbine blade powder, 3-8 parts of interface compatibilizer, and 1.5-5 parts of auxiliary additives to a high-speed mixer and heat and mix at a temperature of 90-110℃ to obtain a premix.

[0028] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained.

[0029] The mass-to-volume ratio of decommissioned wind turbine blade powder to an ethanol aqueous solution containing an anhydride compound and a silane coupling agent is 1 kg:(10-50) L; the ethanol aqueous solution containing the anhydride compound and the silane coupling agent has a mass percentage concentration of 2%-5% and a mass percentage concentration of 1%-3%, and the solvent is an ethanol aqueous solution of ethanol and water mixed in a volume ratio of 1:(0.5-1.5).

[0030] In practical applications, retired wind turbine blade powder is the waste powder of wind turbine blades made from raw materials such as glass fiber and epoxy resin in the existing technology. The embodiments of the present invention transform retired wind turbine blade powder from "waste" into "functional filler" through a specific interface compatibility system and process. While realizing resource utilization, it also significantly improves the mechanical properties, heat resistance and dimensional stability of wood-plastic composite materials.

[0031] In a preferred embodiment of the present invention, the particle size of the decommissioned wind turbine blade powder is 80-400 mesh. Preferably, the particle size of the decommissioned wind turbine blade powder has a bimodal distribution, that is, the decommissioned wind turbine blade powder is a mixture of 80-150 mesh powder and 250-400 mesh powder; the mass ratio of 80-150 mesh fine powder to 250-400 mesh coarse powder is preferably 1:(0.5-1.5), wherein the coarse powder can play a skeletal support role, while the fine powder can better fill the gaps. The two work together to help form a denser packing structure and improve the rigidity and density of the wood-plastic composite material.

[0032] In a preferred embodiment of the present invention, the silane coupling agent is KH-550 or KH-570; the acid anhydride compound is [3-(trimethoxysilyl)propyl]succinic anhydride; the embodiments of the present invention use [3-(trimethoxysilyl)propyl]succinic anhydride in combination with a silane coupling agent to modify the surface of decommissioned wind turbine blade powder, which can play a synergistic role and achieve deep modification of the surface of decommissioned wind turbine blade powder from physical structure to chemical properties; specifically, [3-(trimethoxysilyl)propyl]succinic anhydride has high reactivity, and its... It can preferentially react with the hydroxyl and amino groups remaining in the epoxy resin network in the decommissioned wind turbine blade powder to form strong ester or amide bonds, and can also provide more active reaction sites for the surface modification of silane coupling agents. In addition, [3-(trimethoxysilyl)propyl]succinic anhydride is acidic in aqueous ethanol solution, which can not only etch the smooth skin of the glass fiber surface in the decommissioned wind turbine blade powder to increase its surface roughness, but also lower the pH value of the aqueous ethanol solution, providing a better pH environment for the surface modification of silane coupling agents.

[0033] In a preferred embodiment of the present invention, the thermoplastic is one or more of polyethylene, polypropylene, and polyvinyl chloride; the plant fiber powder is one or more of wood flour, bamboo flour, and rice husk powder, with a particle size of 40-100 mesh; the auxiliary additives include one or more of lubricants, antioxidants, and light stabilizers. In practical applications, high-density polyethylene can be selected as the polyethylene; zinc stearate and / or polyethylene wax can be used as the lubricant; phenolic antioxidants such as antioxidant 1010 or antioxidant 1076 can be used; and benzotriazole light stabilizers such as UV-326 or UV-327 can be used.

[0034] In a preferred embodiment of the present invention, the interface compatibilizer comprises maleic anhydride-grafted polyolefin and an epoxy-functionalized polymer, specifically a mixture of maleic anhydride-grafted polyolefin and epoxy-functionalized polymer at a mass ratio of 1:(0.3-0.7). Preferably, the maleic anhydride-grafted polyolefin is maleic anhydride-grafted polyethylene or maleic anhydride-grafted polypropylene; the epoxy-functionalized polymer is ethylene-acrylate-glycidyl methacrylate, specifically the commercially available Arkema AX8900 product. In this embodiment of the invention, maleic anhydride-grafted polyolefins mainly improve the compatibility between the polyolefin matrix and plant fibers. The epoxy groups in epoxy functional polymers (such as ethylene-acrylate-glycidyl methacrylate) can not only react with the hydroxyl groups of plant fibers, but also react chemically with the residual functional groups of epoxy resin in decommissioned wind turbine blade powder and the silanol groups on the surface of glass fibers. This creates a bridging chemical crosslinking network between the decommissioned wind turbine blade powder, thermoplastic plastic, and plant fiber powder, thus synergistically improving the compatibility of the multiphase interface.

[0035] Example 1: This example provides a wood-plastic composite material modified from decommissioned wind turbine blade powder, the preparation method of which includes the following steps:

[0036] S1. 4 kg of decommissioned wind turbine blade powder with a particle size of 100 mesh and 4 kg of decommissioned wind turbine blade powder with a particle size of 300 mesh were heat-treated at 100℃ for 5 hours. Then, they were placed in 240 L of an ethanol aqueous solution containing 4 wt% [3-(trimethoxysilyl)propyl]succinic anhydride and 2 wt% silane coupling agent KH-550 (ethanol and water volume ratio of 1:1), stirred continuously, and heated to 50℃ for surface wetting treatment for 2 hours. Then, they were dried at 90℃ to obtain the pretreated decommissioned wind turbine blade powder.

[0037] S2. Weigh 3 kg of wood flour with a particle size of 80 mesh, 4 kg of high-density polyethylene, 2 kg of the pretreated decommissioned wind turbine blade powder, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add them all to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0038] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0039] Example 2: This example provides a wood-plastic composite material modified from decommissioned wind turbine blade powder, the preparation method of which includes the following steps:

[0040] S1. 4 kg of decommissioned wind turbine blade powder with a particle size of 100 mesh and 4 kg of decommissioned wind turbine blade powder with a particle size of 300 mesh were heat-treated at 100℃ for 5 hours. Then, they were placed in 240 L of an ethanol aqueous solution containing 4 wt% [3-(trimethoxysilyl)propyl]succinic anhydride and 2 wt% silane coupling agent KH-550 (ethanol and water volume ratio of 1:1), stirred continuously, and heated to 50℃ for surface wetting treatment for 2 hours. Then, they were dried at 90℃ to obtain the pretreated decommissioned wind turbine blade powder.

[0041] S2. Weigh 2.5 kg of wood flour with a particle size of 80 mesh, 4 kg of high-density polyethylene, 2.5 kg of the pretreated decommissioned wind turbine blade powder, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add all of them to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0042] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0043] Example 3: This example provides a wood-plastic composite material modified with decommissioned wind turbine blade powder, the preparation method of which includes the following steps:

[0044] S1. 4 kg of decommissioned wind turbine blade powder with a particle size of 100 mesh and 4 kg of decommissioned wind turbine blade powder with a particle size of 300 mesh were heat-treated at 100℃ for 5 hours. Then, they were placed in 240 L of an ethanol aqueous solution containing 4 wt% [3-(trimethoxysilyl)propyl]succinic anhydride and 2 wt% silane coupling agent KH-550 (ethanol and water volume ratio of 1:1), stirred continuously, and heated to 50℃ for surface wetting treatment for 2 hours. Then, they were dried at 90℃ to obtain the pretreated decommissioned wind turbine blade powder.

[0045] S2. Weigh 2 kg of wood flour with a particle size of 80 mesh, 3.5 kg of high-density polyethylene, 3.5 kg of the pretreated decommissioned wind turbine blade powder, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add them all to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0046] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0047] Example 4: This example provides a wood-plastic composite material modified from decommissioned wind turbine blade powder, the preparation method of which includes the following steps:

[0048] S1. 8 kg of decommissioned wind turbine blade powder with a particle size of 200 mesh was heat-treated at 100℃ for 5 h, and then placed in 240 L of an ethanol aqueous solution containing 4 wt% [3-(trimethoxysilyl)propyl]succinic anhydride and 2 wt% silane coupling agent KH-550 (ethanol and water volume ratio of 1:1). The mixture was continuously stirred and heated to 50℃ for surface wetting treatment for 2 h, and then dried at 90℃ to obtain pretreated decommissioned wind turbine blade powder.

[0049] S2. Weigh 2 kg of wood flour with a particle size of 80 mesh, 3.5 kg of high-density polyethylene, 3.5 kg of the pretreated decommissioned wind turbine blade powder, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add them all to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0050] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0051] Example 5: This example provides a wood-plastic composite material modified from decommissioned wind turbine blade powder, the preparation method of which includes the following steps:

[0052] S1. 4 kg of decommissioned wind turbine blade powder with a particle size of 80 mesh and 2 kg of decommissioned wind turbine blade powder with a particle size of 400 mesh were heat-treated at 80°C for 4 hours. Then, they were placed in 60 L of an ethanol-water solution containing 2 wt% [3-(trimethoxysilyl)propyl]succinic anhydride and 1 wt% silane coupling agent KH-570 (volume ratio of ethanol to water is 1:0.5), stirred continuously, and heated to 40°C for surface wetting treatment for 1 hour. Then, they were dried at 80°C to obtain the pretreated decommissioned wind turbine blade powder.

[0053] S2. Weigh 2 kg of bamboo powder with a particle size of 40 mesh, 5 kg of polypropylene, 1.5 kg of the pretreated decommissioned wind turbine blade powder, 0.3 kg of interface compatibilizer, 0.1 kg of zinc stearate, 0.02 kg of antioxidant 1076, and 0.03 kg of light stabilizer UV-327, and add all of them to a high-speed mixer. Heat and mix at 90°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polypropylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.3.

[0054] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 150℃, Zone 2 160℃, Zone 3 170℃, Zone 4 175℃, Die head 180℃; Screw speed is 200 rpm.

[0055] Example 6: This example provides a wood-plastic composite material modified from decommissioned wind turbine blade powder, the preparation method of which includes the following steps:

[0056] S1. 4 kg of decommissioned wind turbine blade powder with a particle size of 150 mesh and 6 kg of decommissioned wind turbine blade powder with a particle size of 250 mesh were heat-treated at 110°C for 6 hours. Then, they were placed in 500 L of an ethanol aqueous solution containing 5 wt% [3-(trimethoxysilyl)propyl]succinic anhydride and 3 wt% silane coupling agent KH-550 (ethanol to water volume ratio of 1:1.5), stirred continuously, and heated to 60°C for surface wetting treatment for 3 hours. Then, they were dried at 100°C to obtain the pretreated decommissioned wind turbine blade powder.

[0057] S2. Weigh 2 kg of 100-mesh wood flour, 2 kg of 100-mesh rice husk powder, 3 kg of polyvinyl chloride, 3.5 kg of the pretreated decommissioned wind turbine blade powder, 0.8 kg of interface compatibilizer, 0.3 kg of polyethylene wax, 0.1 kg of antioxidant 1010, and 0.1 kg of light stabilizer UV-326, and add all of them to a high-speed mixer. Heat and mix at 110°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.7.

[0058] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 160℃, Zone 2 170℃, Zone 3 180℃, Zone 4 185℃, Die head 190℃; Screw speed is 350 rpm.

[0059] Comparative Example 1: This comparative example provides a wood-plastic composite material, which differs from Example 1 mainly in that it does not contain decommissioned wind turbine blade powder. Its specific preparation method includes the following steps:

[0060] S1. Weigh 3 kg of wood flour with a particle size of 80 mesh, 6 kg of high-density polyethylene, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add them all to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0061] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0062] Comparative Example 2: This comparative example provides a wood-plastic composite material. The main difference from Example 3 is that the decommissioned wind turbine blade powder is added directly without pretreatment. The specific preparation method includes the following steps:

[0063] S1. Mix 4 kg of decommissioned wind turbine blade powder with a particle size of 100 mesh with 4 kg of decommissioned wind turbine blade powder with a particle size of 300 mesh to obtain the mixed decommissioned wind turbine blade powder.

[0064] S2. Weigh 2 kg of wood flour with a particle size of 80 mesh, 3.5 kg of high-density polyethylene, 3.5 kg of the above-mentioned mixed decommissioned wind turbine blade powder, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add them all to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0065] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0066] Comparative Example 3: This comparative example provides a wood-plastic composite material, which differs from Example 3 mainly in the pretreatment method of the decommissioned wind turbine blade powder. Its specific preparation method includes the following steps:

[0067] S1. 4 kg of decommissioned wind turbine blade powder with a particle size of 100 mesh and 4 kg of decommissioned wind turbine blade powder with a particle size of 300 mesh were heat-treated at 100℃ for 5 hours. Then, they were placed in 240 L of an ethanol aqueous solution containing 2 wt% silane coupling agent KH-550 (ethanol and water volume ratio of 1:1), stirred continuously, and heated to 50℃ for surface wetting treatment for 2 hours. Then, they were dried at 90℃ to obtain the pretreated decommissioned wind turbine blade powder.

[0068] S2. Weigh 2 kg of wood flour with a particle size of 80 mesh, 3.5 kg of high-density polyethylene, 3.5 kg of the pretreated decommissioned wind turbine blade powder, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add them all to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0069] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0070] Comparative Example 4: This comparative example provides a wood-plastic composite material, which differs from Example 3 mainly in the pretreatment method of the decommissioned wind turbine blade powder. Its specific preparation method includes the following steps:

[0071] S1. 4 kg of decommissioned wind turbine blade powder with a particle size of 100 mesh and 4 kg of decommissioned wind turbine blade powder with a particle size of 300 mesh were heat-treated at 100℃ for 5 h, and then placed in 240 L of an ethanol aqueous solution containing 4 wt% [3-(trimethoxysilyl)propyl]succinic anhydride (ethanol and water volume ratio of 1:1), stirred continuously, and heated to 50℃ for surface wetting treatment for 2 h, and then dried at 90℃ to obtain pretreated decommissioned wind turbine blade powder.

[0072] S2. Weigh 2 kg of wood flour with a particle size of 80 mesh, 3.5 kg of high-density polyethylene, 3.5 kg of the pretreated decommissioned wind turbine blade powder, 0.5 kg of interface compatibilizer, 0.2 kg of polyethylene wax, 0.05 kg of antioxidant 1010, and 0.05 kg of light stabilizer UV-326, and add them all to a high-speed mixer. Heat and mix at 100°C to obtain a premix. The interface compatibilizer is a mixture of maleic anhydride-grafted polyethylene and ethylene-acrylate-glycidyl methacrylate (AX8900) at a mass ratio of 1:0.5.

[0073] S3. The above premixed material is fed into a twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the modified wood-plastic composite material can be obtained. The parameters of the twin-screw extruder are set as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die head 185℃; Screw speed is 300 rpm.

[0074] Performance testing: The modified wood-plastic composite materials prepared in Examples 1-4 and the wood-plastic composite materials prepared in Comparative Examples 1-4 were injection molded into standard specimens, and then their performance was tested under the same test conditions. The results are shown in Table 1.

[0075] Table 1

[0076] Test Project Bending strength (MPa) Flexural modulus (GPa) <![CDATA[Notched impact strength (KJ / m 2 )]]> Water absorption rate (24h, %) Heat distortion temperature (1.82 MPa, °C) Example 1 38.5 2.8 5.2 0.8 78 Example 2 41.2 3.1 4.9 0.7 82 Example 3 45.8 3.6 4.5 0.6 86 Example 4 40.5 2.9 4.1 0.9 80 Comparative Example 1 32.1 2.1 3.8 1.5 65 Comparative Example 2 28.4 1.9 3.1 1.8 70 Comparative Example 3 35.2 2.5 4.0 1.2 75 Comparative Example 4 33.5 2.4 3.9 1.4 73

[0077] As can be seen from Table 1, compared with not adding retired wind turbine blade powder or directly adding untreated retired wind turbine blade powder, the embodiments of the present invention can significantly improve the mechanical properties and heat resistance of wood-plastic composites and reduce the water absorption rate of wood-plastic composites by adding retired wind turbine blade powder that has been surface modified with [3-(trimethoxysilyl)propyl]succinic anhydride and silane coupling agent.

[0078] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification.

Claims

1. A wood-plastic composite material modified from decommissioned wind turbine blade powder, characterized in that, It includes the following components by weight: 20-40 parts plant fiber powder, 30-50 parts thermoplastic plastic, 15-35 parts pretreated decommissioned wind turbine blade powder, 3-8 parts interface compatibilizer, and 1.5-5 parts auxiliary additives. The pretreatment method for the decommissioned wind turbine blade powder is: surface modification using a silane coupling agent.

2. The wood-plastic composite material modified from decommissioned wind turbine blade powder according to claim 1, characterized in that, The pretreatment method for the decommissioned wind turbine blade powder specifically includes the following steps: After heat treatment at 80-110℃, the decommissioned wind turbine blade powder is then surface-wetted in an ethanol aqueous solution containing acid anhydride compounds and silane coupling agents, and then dried to obtain pretreated decommissioned wind turbine blade powder.

3. The wood-plastic composite material modified from decommissioned wind turbine blade powder according to claim 2, characterized in that, In the ethanol-water solution containing the acid anhydride compound and the silane coupling agent, the mass percentage concentration of the acid anhydride compound is 2%-5%, and the mass percentage concentration of the silane coupling agent is 1%-3%.

4. The decommissioned wind turbine blade powder-modified wood-plastic composite material according to claim 1 or 2, characterized in that, The particle size of the decommissioned wind turbine blade powder is 80-400 mesh.

5. The decommissioned wind turbine blade powder-modified wood-plastic composite material according to claim 2 or 3, characterized in that, The acid anhydride compound is [3-(trimethoxysilyl)propyl]succinic anhydride.

6. The wood-plastic composite material modified from decommissioned wind turbine blade powder according to claim 1, characterized in that, The thermoplastic is one or more of polyethylene, polypropylene, and polyvinyl chloride; the plant fiber powder is one or more of wood powder, bamboo powder, and rice husk powder.

7. The wood-plastic composite material modified from decommissioned wind turbine blade powder according to claim 1, characterized in that, The interface compatibilizer includes maleic anhydride-grafted polyolefins and epoxy functional group polymers.

8. The decommissioned wind turbine blade powder modified wood-plastic composite material according to claim 7, characterized in that, The maleic anhydride-grafted polyolefin is maleic anhydride-grafted polyethylene or maleic anhydride-grafted polypropylene; the epoxy functional polymer is ethylene-acrylate-glycidyl methacrylate.

9. The wood-plastic composite material modified from decommissioned wind turbine blade powder according to claim 1, characterized in that, The auxiliary additives include one or more of lubricants, antioxidants, and light stabilizers.

10. A method for preparing a wood-plastic composite material modified from decommissioned wind turbine blade powder as described in any one of claims 1-9, characterized in that, Includes the following steps: Weigh out the plant fiber powder, thermoplastic plastic, pretreated decommissioned wind turbine blade powder, interface compatibilizer, and auxiliary additives according to the weight proportions of the above components. Plant fiber powder, thermoplastic plastic, pretreated decommissioned wind turbine blade powder, interface compatibilizer, and auxiliary additives are heated and mixed to obtain a premix. The premixed material is melt-blended, extruded, cooled, and pelletized to obtain a modified wood-plastic composite material.