Regenerated GFRP (Glass Fiber Reinforced Plastic) reinforced wood-based composite material of retired fan blade with bionic gradient structure and preparation process of regenerated GFRP reinforced wood-based composite material

Abstract

The invention discloses a retired fan blade regenerated GFRP reinforced wood-based composite material with a bionic gradient structure and a preparation process thereof, the composite material comprises five layers of orthogonal paving structures, and the five layers of orthogonal paving structures comprise a surface layer, a middle layer, a core layer, a middle layer and a surface layer according to the weight distribution ratio of 1: 2: 4: 2: 1 in parts by weight, wherein the surface layer and the core layer adopt a mixture of longitudinally paved GFRP particles of 2-4 meshes and poplar wood shavings, and the preparation process comprises the following steps: crushing and screening the retired fan blade to obtain three groups of GFRP particles of 2-4 meshes, 4-8 meshes and 8-20 meshes; respectively mixing the GFRP with the poplar wood shavings according to the surface layer material, the middle layer material and the core layer material; sizing the mixture by using a phenolic resin adhesive; orthogonally paving in a mold; the preparation method comprises the following steps: pre-pressing at 2MPa for 60s, and carrying out hot press molding, so that the obtained composite material is designed through a five-layer orthogonal bionic gradient structure, the high-strength characteristic of regenerated GFRP is reserved, excellent mechanical properties, water resistance and interlayer stress coordination capability are realized, and the composite material has the advantages of stable interface bonding and environment-friendly regeneration.

Description

Technical Field

[0001] The invention relates to the technical field of composite material manufacturing, in particular to a GFRP-reinforced wood-based composite material with a bionic gradient structure and a preparation process thereof for a regenerated GFRP-reinforced wood-based composite material for retired wind turbine blades. Background Art

[0002] Wood-based composites (WBCs) are composite materials made of wood materials as the matrix and reinforced by adding polymers, inorganic non-metallic materials and nanomaterials. They have excellent mechanical properties, aging resistance and flame retardancy and are widely used in the fields of construction, furniture and packaging. At present, the reinforcing materials commonly used to prepare wood-based composites mainly include fibers (glass fibers, carbon fibers and plant fibers, etc.), particles (plastic particles, metal particles and ceramic particles) and nanomaterials (nanocellulose, carbon nanotubes and nanoclay, etc.), which improve the shortcomings of traditional wood materials such as poor water resistance and low mechanical strength. However, due to the polarity difference between wood materials and most reinforcing materials, the interface compatibility between the two is poor, resulting in processing difficulties, strict equipment and technical requirements, and problems such as excessive gaps, poor dispersion and agglomeration inside the material, which affect the overall performance and application range of the composite materials. With the increasing demand for high-performance composite materials and the deepening of green and low-carbon environmental awareness, it is still necessary to continue to optimize the preparation method of wood-based composite materials to improve material performance and reduce production energy consumption and pollution.

[0003] Introducing high-performance reinforcing phases to prepare wood-based composite materials is an effective way to improve material performance and broaden the application field. In order to meet the green transformation needs of the entire chain of economic and social development and reduce dependence on non-renewable resources, researchers have developed a new type of wood-based composite material prepared by mixing high-strength and corrosion-resistant retired wind turbine blade recycled glass fiber reinforced resin (Glass Fiber-reinforced Polymers, GFRP) with wood materials as reinforcing phases. The relevant cases are as follows: CN117534888A provides a preparation method and product of wind turbine blade recycled material reinforced wood-plastic composite materials. After low-temperature plasma treatment of the recycled resin powder of the discarded wind turbine blade obtained by mechanical processing, it is blended with the wind turbine blade recycled fiber reinforced polyolefin masterbatch obtained by the granulation process, maleic anhydride grafted polyolefin, wood processing residues and other additives, and granulated and extruded to obtain wood-plastic composite materials. Although the invention improves the compatibility of glass fiber with biomass fiber, polyolefin and other materials through plasma modification, it has the problems of complex preparation process and high energy consumption cost. CN119286127A also uses wind turbine blade recycled glass fiber to prepare wood-plastic composite materials. Wind turbine blade powder material (WGFRP, particle size 40-120 mesh), wood powder, PP resin, calcium bicarbonate and other additives are mixed in proportion, and a wood-plastic composite material with strong mechanical properties and weather resistance is prepared through banburying, hot pressing and cold pressing. Although this invention effectively overcomes the defects of insufficient performance of wood-plastic composite materials and reduces the use of plastics, it is similar to CN117534888A, and still fails to achieve complete renewability of raw materials for preparation, and the effect of energy saving and emission reduction is general. CN119458730A discloses an application and manufacturing method of retired wind turbine blades in the manufacture of new board materials. After cutting and crushing the retired wind turbine blades, glass fiber powder (diameter ≤3mm), epoxy resin powder, PVC / PET powder and balsa wood powder in the blades are separated through multi-stage screening. After mixing these components, glue is applied, and multi-stage sweeping is performed, and finally a new board with high economic value and good waterproofness is obtained through hot pressing and cold pressing. Although this method realizes the resource utilization of retired wind turbine blade components, the recycling process requires repeated crushing-screening-separation operations. The process of recycling GFRP is cumbersome and has great damage to the performance of GFRP itself. At the same time, Zhang et al. pointed out that the epoxy resin on the surface of GFRP will hinder its close interface with wood materials, resulting in a weak interface layer in the wood-based composite material. Therefore, it is still necessary to further explore the structural regulation strategy and performance optimization technology of GFRP-reinforced wood-based composite materials to promote the development of multifunctional integration of materials. A new type of GFRP-reinforced wood-based composite material with a bionic gradient structure for the regeneration of retired wind turbine blades and its preparation process are urgently needed on the market. Summary of the invention

[0004] To achieve the above-mentioned purpose, the present invention provides a GFRP-reinforced wood-based composite material for regenerating retired wind turbine blades with a bionic gradient structure and a preparation process thereof, which solves the above-mentioned technical problems.

[0005] The present invention provides a GFRP reinforced wood-based composite material for regenerating retired wind turbine blades with a bionic gradient structure, comprising a five-layer orthogonal paving structure, distributed by weight in a ratio of 1:2:4:2:1 of surface layer-middle layer-core layer-middle layer-surface layer, wherein the surface layer and the core layer are longitudinally paved with a mixture of 2-4 mesh GFRP particles and poplar shavings.

[0006] Furthermore, the weight ratio of the mixture of GFRP particles and poplar wood shavings is 3:7.

[0007] Furthermore, the middle layer is a mixture of 4-8 mesh GFRP particles and poplar wood shavings laid transversely, and the weight ratio of GFRP to wood shavings is 3:7.

[0008] The present invention provides a preparation process of a regenerated GFRP reinforced wood-based composite material for retired wind turbine blades with a bionic gradient structure, comprising the following steps:

[0009] (a) crushing and screening retired fan blades to obtain three groups of GFRP particles: 2-4 mesh, 4-8 mesh, and 8-20 mesh;

[0010] (b) mixing GFRP and poplar wood shavings in a weight ratio of 3:7 for the surface layer material, the middle layer material, and the core layer material;

[0011] (c) applying phenolic resin adhesive to the mixture;

[0012] (d) orthogonally paving in a mold in a weight ratio of 1:2:4:2:1 of surface layer-middle layer-core layer-middle layer-surface layer;

[0013] (e) After pre-pressing at 2 MPa for 60 s, hot pressing was performed at 5 MPa and 180°C.

[0014] Furthermore, in step (c), the amount of phenolic resin adhesive applied to the mixture is 10 wt %.

[0015] Furthermore, after step (a), the method further includes: placing the GFRP particles in an argon plasma treatment device, treating them at a power of 300 W for 5 minutes, and maintaining the pressure of the treatment chamber at 50-80 Pa.

[0016] Furthermore, in step (d), a transition layer is inserted between the surface layer and the middle layer, and the preparation of the transition layer includes: mixing 2-4 mesh and 4-8 mesh GFRP particles in a ratio of 1:1; paving at a 45° direction, and controlling the layer thickness to be 1.5-2.0 mm.

[0017] Furthermore, the hot pressing process of step (e) is divided into two stages: the first stage: 2MPa pressure, hot pressing at 160°C for 5 minutes; the second stage: rising to 5MPa, hot pressing at 180°C for 8 minutes.

[0018] Furthermore, the hot pressing process of step (e) is divided into two stages: the first stage: 2MPa pressure, hot pressing at 160°C for 5 minutes; the second stage: rising to 5MPa, hot pressing at 180°C for 8 minutes.

[0019] Furthermore, the glue application uses a dual-fluid atomizing spray gun, the atomizing pressure is 0.3-0.5MPa, and the adhesive droplet particle size is 50-80μm.

[0020] Furthermore, the method further comprises step (f) curing the hot pressed slab in an environment of 20±2° C. and 65±5% relative humidity for 48 hours.

[0021] Furthermore, a mold system dedicated to the preparation of recycled GFRP-reinforced wood-based composite materials with bionic gradient structures for retired wind turbine blades has a core structure including: mold body: equipped with layered paving grooves and edge racks to support precise positioning; hydraulic pre-pressing module: driven by a hydraulic cylinder to achieve 2MPa pre-pressing of the lower support plate, and hot pressing molding is completed with the upper pressure plate assembly with a heating device; fast disassembly and assembly design: the snap-on pressure plate assembly cooperates with the limit groove to achieve fast clamping and demolding of the finished product. The mold integrates paving, pre-pressing, and hot pressing functions into one, shortens the process time, integrates traditional multiple processes into continuous production, significantly improves preparation efficiency, shortens pre-pressing time by 40%, and ensures the interlayer bonding quality through precise temperature and pressure control.

[0022] Furthermore, an orthogonal paving equipment for preparing GFRP-reinforced wood-based composite materials recycled from retired wind turbine blades with a bionic gradient structure has the following technical features: multi-directional paving mechanism: through the gear-rack transmission linkage directional roller group, with the rotatable partition bin to achieve longitudinal / lateral / 45° paving direction switching; unpowered material distribution system: using counter-rotating distribution rollers to evenly disperse the GFRP-wood mixture, the atomized adhesive penetrates into the material surface through the gap between the directional rollers; modular silos: the four-partition rotating silo supports the precise quantitative delivery of surface, middle and core layer materials, with the error controlled within ±2%. The equipment does not require external energy drive, and realizes the precise construction of a five-layer gradient structure through mechanical linkage, with a paving speed of 1.5m 2 / min, the layer thickness uniformity is 30% higher than that of traditional equipment, which is particularly suitable for customized production.

[0023] The present invention proposes a regenerated GFRP reinforced wood-based composite material with a bionic gradient structure for retired wind turbine blades and a preparation process thereof, which has the following beneficial effects:

[0024] 1. The present invention simplifies the recycling process, retains the original properties of the recycled materials to the greatest extent, applies them as reinforcing materials to wood-based composite materials, and cooperates with bionic structural design to construct high-performance and multifunctional wood-based composite materials. The present invention can not only effectively solve the problem of recycling and utilization of wind turbine blade recycled materials, convert industrial waste into high-performance practical resources, but also greatly broaden the performance boundaries of wood-based composite materials. In terms of material performance improvement, through innovative processes and designs, wood-based composite materials have both high strength, high toughness and multifunctional characteristics, breaking through the bottleneck of traditional materials in mechanical properties and functionality. From an environmental protection perspective, it reduces excessive dependence on native wood, reduces the potential harm of wind turbine blade waste to the environment, and contributes a practical solution to green and sustainable development. In application and promotion, due to its excellent performance, it can play a key role in multiple industries, such as helping to create stronger, energy-saving and environmentally friendly building structures in the construction industry; in the field of furniture manufacturing, it can produce products that are both beautiful and durable, meeting consumers' dual pursuit of quality and environmental protection. In addition, the technical route adopted by the present invention has scalability and compatibility, and can be combined with other emerging material technologies to further promote the innovative development in the field of materials science and provide ideas and references for the research and development of more high-performance and multifunctional materials in the future;

[0025] 2. There are several main problems with wood-based composite materials: (1) material performance defects (insufficient weather resistance, low dimensional stability, and limited mechanical properties); (2) processing and process challenges (interface compatibility issues and high processing energy consumption costs); (3) market and application defects (insufficient cost competitiveness and scarcity of high-end products); (4) environmental and sustainable development issues (source of raw materials). The five-layer orthogonal paving structure of this application greatly improves the static bending strength;

[0026] 3. There are several main problems with the recycled GFRP-reinforced wood-based composites from retired wind turbine blades: (1) performance defects of recycled materials (materials are damaged during the recycling process); (2) poor interface bonding of composite materials, resulting in low performance (low interface bonding strength); (3) challenges in economy and scale (high recycling cost, unstable raw material supply and limited application scenarios). This application, through the three-in-one technical innovation of "gradient structure design-interface strengthening-scale process", makes the recycled GFRP-reinforced wood-based composites surpass the existing technology in terms of performance, cost and sustainability, and provides an industrialized implementation plan for the circular economy of wind turbine blades.

[0027] 4. The present invention imitates the natural layered structure of nacre and innovatively designs a wood-based composite material with a five-layer structure, which significantly improves the interfacial bonding strength of the material. Recycled glass fibers from retired wind turbine blades of different specifications are embedded in a poplar wood shavings matrix as a reinforcing phase. After paving them in a criss-cross pattern, a bionic gradient wood-based composite material with high strength, toughness and corrosion resistance is obtained through hot pressing. This technology further expands the development potential of wood-based composite materials in sustainable economy and multi-scenario applications, and provides a practical basis for the high-value recycling of waste in the wind power industry;

[0028] 5. The mold system and orthogonal paving equipment involved in this application for preparing the regenerated GFRP-reinforced wood-based composite materials with bionic gradient structures from retired wind turbine blades form a closed production unit, integrating the traditional 8 processes into 3 continuous operations, greatly reducing the production line footprint, and enhancing the interlayer bonding strength of the composite materials through precise control of hydraulic preloading (2MPa) and gradient hot pressing, ensuring the performance improvement of the composite materials, and the equipment paving accuracy makes the material utilization rate reach 98.5%, which is conducive to achieving carbon emission reduction in conjunction with the retired material regeneration technology. This technical system successfully solves the bottleneck problems of poor equipment adaptability and complex processes in the industrialization of recycled GFRP-reinforced wood-based composite materials, and provides a complete equipment solution for the large-scale application of green building materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the mechanism of regenerating GFRP reinforced wood-based composite materials with bionic gradient structures from retired wind turbine blades prepared in Example 1 of the present invention;

[0030] Figure 2 This is a graph showing the anti-corrosion performance of the regenerated GFRP reinforced wood-based composite material having a bionic gradient structure of a retired wind turbine blade prepared in Example 1 of the present invention;

[0031] Figure 3 The mold structure of Example 1 of the present invention is shown in FIG. Figure 1 ;

[0032] Figure 4 The mold structure of Example 1 of the present invention is shown in FIG. Figure 2 ;

[0033] Figure 5 The mold structure of Example 1 of the present invention is shown in FIG. Figure 3 ;

[0034] Figure 6 Schematic diagram of the paving equipment structure of Example 1 of the present invention Figure 1 ;

[0035] Figure 7 Schematic diagram of the paving equipment structure of Example 1 of the present invention Figure 2 ;

[0036] Figure 8 Schematic diagram of the paving equipment structure of Example 1 of the present invention Figure 3 ;

[0037] Fig. 9 Schematic diagram of the paving equipment structure of Example 1 of the present invention Figure 4 ;

[0038] Description of the markings in the figure:

[0039] Mould body 1; edge groove 2; rack 3; limit groove 4; hydraulic cylinder 5; lower support plate 7; heating device 8; upper pressure plate 9; support column 10; clamping block 11; pull column 12; reinforcing rib 13; shell 14; gear one 15; limit column 16; spring 17; gear two 18; directional rod 19; belt one 20; baffle 21; triangular material plate 22; belt two 23; material dividing rod 24; knob 25; central rotating rod 26; feed port 27; handrail 28; protective buckle plate 29; partition 30. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0041] Unless otherwise specified, the examples and comparative examples are parallel tests with the same components, component contents, preparation steps and preparation parameters. The test methods in the following examples are conventional methods unless otherwise specified. The test materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0042] Unless otherwise stated, all reagents were used as received without further purification.

[0043] In the preparation examples and embodiments of the present invention, the “parts” are parts by weight unless otherwise specified, and the concentration percentages are concentrations by weight unless otherwise specified.

[0044] Example 1

[0045] Step (1), the GFRP used is cut and crushed from retired wind turbine blades, and then sieved through sieves of different mesh sizes to obtain three specifications of 2-4 mesh, 4-8 mesh, and 8-20 mesh;

[0046] Step (2), using GFRP of different specifications (2-4 mesh, 4-8 mesh, 8-20 mesh) as reinforcing materials, and mixing them with poplar wood shavings in a weight ratio of 3:7, using the mixture of 2-4 mesh GFRP and wood shavings as the surface layer material, the mixture of 4-8 mesh GFRP and wood shavings as the middle layer material, and the mixture of 8-20 mesh GFRP and wood shavings as the core layer material;

[0047] Step (3), using phenolic resin 85 as an adhesive, with an application amount of 10%, applying adhesive to the surface material, the middle layer material and the core layer material respectively, using a dual-fluid atomizing spray gun, with an atomizing pressure of 0.3-0.5 MPa, and an adhesive droplet size of 50-80 μm, spraying the phenolic resin adhesive on the poplar wood shavings to mix the glue, and fully stirring for 10 minutes to obtain wood shavings with uniform glue application;

[0048] Step (4), using a paving device to fill the glued wood chips into a 300×300×12 mm mold, the material structure is 5 layers, the weight of the surface layer, the middle layer, the core layer, the middle layer and the surface layer are distributed in a ratio of 1:2:4:2:1, and the adjacent layers are paved orthogonally, that is, the paving directions of the upper and lower surface layers and the core layer wood chips are consistent, all longitudinal, and the paving directions of the middle layer wood chips are all transverse;

[0049] Step (5), remove the paving equipment from the mold, install the upper pressing plate assembly on the mold, press the upper pressing plate assembly on the paved slab, drive the lower support plate 7 upward through the hydraulic telescopic cylinder 5, and apply pressure to the slab. The pre-pressing pressure is 2MPa and the time is 60s, so that the slab has a certain density and initial bonding strength, and the slab forming weight is increased;

[0050] Step (6), start the heating device 8 provided at the lower end of the lower support plate 7, and hot press for 13 minutes under the conditions of hot pressing pressure of 5 MPa and 180°C to obtain a preset density of 850 kg / m 3 , composite material with dimensions of 300×300×12mm;

[0051] Step (7), after hot pressing, the slab is cooled and cured for 2 days in an environment of 20±2°C and relative humidity of 65±5%, so as to eliminate the stress generated during the material processing, improve dimensional stability and balance the moisture content, and finally obtain a retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a bionic gradient structure.

[0052] Example 2

[0053] The difference from Example 1 is that a plasma activation treatment is added after step (1): the sieved GFRP particles are placed in a plasma treatment device and treated at a power of 300 W for 5 minutes under an argon atmosphere, the surface oxygen content is 28-32 at%, and a nano-groove structure with Ra = 1.2-1.8 μm is formed;

[0054] In step (4), a transition layer structure is introduced: a transition layer is added between the surface layer and the middle layer, the transition layer is made of a mixture of 2-4 mesh and 4-8 mesh GFRP in a ratio of 1:1, and the paving direction of the transition layer wood chips is at a 45° angle with the adjacent layer;

[0055] In step (6), a segmented hot pressing process is adopted: the first stage: hot pressing at 2 MPa pressure and 160°C for 5 minutes to allow the adhesive to fully penetrate into the grooves on the GFRP surface; the second stage: hot pressing at 5 MPa and 180°C for 8 minutes to complete cross-linking and curing, and the rest is the same as in the embodiment.

[0056] Example 3

[0057] The only difference from Example 1 is that the weight ratio of GFRP to poplar wood shavings in step (2) is 1:9, and the rest is the same as Example 1.

[0058] Example 4

[0059] The only difference from Example 1 is that the weight ratio of GFRP to poplar wood shavings in step (2) is 2:8, and the rest is the same as Example 1.

[0060] Example 5

[0061] The only difference from Example 1 is that the weight ratio of GFRP to poplar wood shavings in step (2) is 4:6, and the rest is the same as Example 1.

[0062] Example 6

[0063] The only difference from Example 1 is that the GFRP used in step (1) is obtained by cutting and crushing waste sheet molding compound (SMC) automobile parts, and the rest is the same as Example 1.

[0064] Example 7

[0065] like Figure 3-Figure 9 As shown, the mold comprises a mold body 1, a mold groove is provided in the middle of the mold body 1, edge grooves 2 are provided on four sides of the mold body 1, a rack 3 is provided in the edge groove 2, and a limiting groove 4 is provided on the mold body 1;

[0066] A hydraulic telescopic cylinder 5 is fixed at the bottom of the mold body 1, and the output end of the hydraulic telescopic cylinder 5 is fixedly connected to the lower support plate 7. The lower support plate 7 slides in the mold groove, and a heating device 8 is installed at the lower end of the lower support plate 7;

[0067] The upper pressing plate assembly includes an upper pressing plate 9, which is pressed on the upper end of the slab in the mold groove. Support columns 10 are provided at the four corners of the upper pressing plate 9. The support column 10 is rotatably connected to one end of a clamping block 11, and the other end of the clamping block 11 is clamped in the limiting groove 4. A pulling column 12 and a reinforcing rib 13 are provided on the upper pressing plate 9.

[0068] The working principle of the above technical solution is as follows: the paving equipment is used to fill the mold groove in the mold with the glued wood shavings, the lower surface of the paved slab contacts the lower support plate 7, the paving equipment is removed from the mold, the upper pressing plate 9 is pressed on the upper end of the slab in the mold groove, the clamping blocks 11 at the four corners of the upper pressing plate 9 are rotated, the clamping blocks 11 and the support column 10 are rotated, the front end of the support column 10 is clamped into the limit groove 4, the hydraulic telescopic cylinder 5 is started, and the lower support plate 7 is driven to move upward, thereby shortening the distance between the lower support plate 7 and the upper pressing plate 9. distance, to achieve pressure on the slab, so that the slab has a certain density and initial bonding strength, increase the forming weight of the slab, start the heating device 8, can be hot pressed on the slab, after the hot pressing is completed, separate the front end of the support column 10 from the limit groove 4, pull the pulling column 12, pull the upper pressing plate assembly out of the mold, start the hydraulic telescopic cylinder 5 again, drive the lower support plate 7, lift the composite material, easy to take out, paving, cold pressing and hot pressing are all completed in the mold groove, which is convenient and fast, greatly reducing the process time and equipment cost.

[0069] Example 8

[0070] like Figure 3-Figure 9 As shown, the paving equipment includes a shell 14, which is slidably connected to the upper end of the mold body 1, and a gear 15 is rotatably connected to the side of the shell 14. The gear 15 and the gear 2 18 are gear meshing transmission. A plurality of directional rods 19 are rotatably connected in the shell 14, and the gear 2 18 is fixedly connected to the directional rod 19 at the edge position, and two adjacent directional rods 19 are connected by a belt 1 20. A baffle 21 and a triangular material plate 22 are fixed in the shell 14, and the directional rod 19 at the edge position is connected by a belt 23 to a material dividing rod 24, and the two material dividing rods 24 are connected by gear meshing transmission;

[0071] The housing 14 is rotatably connected to a central rotating rod 26, the end of which is fixedly connected to a knob 25, and the central rotating rod 26 is fixedly connected to four partitions 30. The upper end of the housing 14 is provided with a feed port 27;

[0072] A handrail 28 is fixed to the side of the housing 14, a protective buckle plate 29 is provided on the outer side of the housing 14, the housing 14 is slidably connected to the limit column 16, a spring 17 is provided between the housing 14 and the limit column 16, and the front end of the limit column 16 is clamped into the limit groove 4;

[0073] The working principle of the above technical solution is as follows: the paving equipment is placed on the mold body 1, the two ends of the shell 14 of the paving equipment are clamped into the edge groove 2, the gear 15 is meshed with the rack 3 in the edge groove 2, and under the pulling force of the spring 17, the front end of the limit column 16 is clamped into the limit groove 4;

[0074] A receiving groove is formed between two adjacent partitions 30, and four receiving grooves are arranged around the central rotating rod 26. The surface shavings of a preset weight are added from the feed port 27, and the surface shavings fall into the first receiving groove. The knob 25 is turned to drive the central rotating rod 26 to rotate, and the four partitions 30 are driven to rotate along with the central rotating rod 26, and the middle layer shavings of a preset weight are added into the second receiving groove. The knob 25 is turned again to add the core layer shavings of a preset weight into the third receiving groove. At this time, the first receiving groove rotates downward, and the surface shavings fall between the two dividing rods 24.

[0075] Push the handrail 28 forward to drive the shell 14 to slide forward on the mold body 1, and the gear 15 meshes with the rack 3 to drive the gear 15 to rotate, drive the gear 2 18 to rotate, drive the directional rod 19 to rotate, and drive multiple directional rods 19 to rotate simultaneously through the belt 1 20. The directional rod 19 at the edge position drives the dividing rod 24 to rotate through the belt 2 23, and drives another dividing rod 24 to rotate through the gear. The two dividing rods 24 rotate in opposite directions to break up the surface material in the first accommodating groove and let it fall. The falling surface shavings are guided by the triangular material smoothing plate 22, and the surface shavings fall between the blades of the directional rod 19. As the directional rod 19 rotates, the surface shavings fall along the edge of the blades of the directional rod 19. The laying direction of the large-distribution surface shavings is perpendicular to the movement direction of the paving equipment, which is longitudinal paving;

[0076] Lift the paving equipment and rotate it 90 degrees so that the two ends of the shell 14 of the paving equipment are against the limit grooves 4 on the other two sides of the mold body 1, thereby changing the paving direction, turning the knob 25 to drive the central rotating rod 26 to rotate, and turning the second receiving groove storing the middle layer of shavings downward, adding the preset weight of the middle layer of shavings from the feed port 27 into the fourth receiving groove, and pushing the handrail 28 forward to drive the shell 14 to slide forward on the mold body 1. The same as the above principle, the middle layer of shavings is laid on the upper layer of the surface shavings, and the laying direction of the middle layer of shavings is opposite to that of the surface layer, which is horizontal paving. Repeating the above operation can realize the paving of the remaining layers, and the paving direction is controllable. Compared with manual paving, the paving is more uniform, does not require power supply, can be operated anytime and anywhere, and is convenient and fast, which greatly shortens the paving time.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that in step (2), equal weight portions of GFRP and poplar wood shavings are not mixed, and the rest are the same.

[0079] Comparative Example 2

[0080] The difference from Example 1 is that in step (2), only 2-4 mesh GFRP is used as the reinforcing material to be mixed with the poplar wood shavings, and the rest are the same.

[0081] Comparative Example 3

[0082] The difference from Example 1 is that in step (2), only 4-8 mesh GFRP is used as the reinforcing material to be mixed with the poplar wood shavings, and the rest is the same.

[0083] Comparative Example 4

[0084] The difference from Example 1 is that in step (2), only 8-20 mesh GFRP is used as the reinforcing material to be mixed with the poplar wood shavings, and the rest are the same.

[0085] Performance Testing

[0086] 1. The composite materials prepared in the examples and comparative examples were tested for static bending strength, elastic modulus, internal bonding strength and water absorption thickness expansion rate. The static bending strength test was based on ISO 16978, the elastic modulus was based on ASTM D1037, the internal bonding strength test was based on ISO 16983, and the water absorption thickness expansion rate test was based on ISO 16979. The results are shown in Table 1.

[0087] Table 1

[0088]

[0089] As can be seen from Table 1, the static bending strength of Example 1 (five-layer orthogonal paving) is greatly improved compared with Comparative Examples 2-4 (single particle size reinforcement), which proves that the bionic gradient design significantly improves the interlaminar stress distribution; the plasma activation treatment of Example 2 can enhance the interfacial bonding strength between GFRP and phenol, improve the internal bonding strength, and reduce the water absorption rate; the introduced transition layer structure and segmented hot pressing process eliminate the interlaminar shear stress concentration and improve the static bending strength.

[0090] 2. Anticorrosion performance test: The pure wood substrate (size: 20×20×5mm) without any anticorrosion treatment was set as the blank group, the regenerated wood-based composite material (WBC) of retired wind turbine blades and the material without GFRP reinforcement were set as the WBC group, and Example 1 was set as the GFRP@WBC group. By simulating microbial corrosion in the natural environment, the antibacterial and corrosion resistance of different materials under the same conditions were compared to verify the effect of the bionic gradient structure of GFRP-reinforced wood-based composite materials on the anticorrosion performance. The mixed bacterial suspension (Trametes versicolor, Aspergillus niger and Penicillium) was evenly sprayed into the culture dish, and the three groups of samples were placed on the surface of the bacterial culture medium (culture medium composition: potato dextrose agar, pH 5.6) and cultured in a constant temperature and humidity chamber at a temperature of 28°C and a humidity of 85% for 14 days. The colony growth area, color change and corrosion of the material surface, such as spots and cracks, were recorded.

[0091] from Figure 2 It can be seen that the phenomenon of the blank group is that the surface of the culture medium is evenly covered with white hyphae (as shown on the left), the wood surface is severely corroded, and obvious holes and softening appear. The wood without antiseptic treatment provides sufficient nutrition for microorganisms, resulting in rapid reproduction and material degradation. The phenomenon of the WBC group is that scattered yellow colony spots appear on the surface of the gray-white wood-based composite material, and the corrosion area accounts for about 35%. The retired wind turbine blade recycling material (WBC) has a high porosity and some areas are invaded by mold, but the anti-corrosion performance is better than the blank group. The phenomenon of the GFRP@WBC group is that there are no visible colonies on the surface of the dark brown square composite material, and only slight hyphae growth occurs on the edge of the culture medium. There is no trace of corrosion on the contact surface between the material and the culture medium, the bionic gradient layer blocks microbial penetration, and the structure of the material is complete. In summary, the gradient structure formed by the high-density GFRP reinforcement layer and the porous wood base layer effectively inhibits the attachment and diffusion of microorganisms.

[0092] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the present invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. A GFRP-reinforced wood-based composite material for regenerating retired wind turbine blades with a bionic gradient structure, characterized in that: It comprises a five-layer orthogonal paving structure, and its weight distribution is 1:2:4:2:1 of surface layer-middle layer-core layer-middle layer-surface layer, wherein the surface layer and the core layer are longitudinally paved with a mixture of 2-4 mesh GFRP particles and poplar wood shavings.

2. The composite material according to claim 1, characterized in that The weight ratio of the mixture of GFRP particles and poplar wood shavings is 3:

7.

3. The composite material according to claim 1, characterized in that The middle layer is a mixture of 4-8 mesh GFRP particles and poplar wood shavings laid horizontally, with the weight ratio of GFRP to wood shavings being 3:

7.

4. The process for preparing the composite material according to claim 1, characterized in that: The following steps are involved: (a) crushing and screening retired fan blades to obtain three groups of GFRP particles: 2-4 mesh, 4-8 mesh, and 8-20 mesh; (b) mixing GFRP and poplar wood shavings in a weight ratio of 3:7 for the surface layer material, the middle layer material, and the core layer material; (c) applying phenolic resin adhesive to the mixture; (d) orthogonally paving in a mold in a weight ratio of 1:2:4:2:1 of surface layer-middle layer-core layer-middle layer-surface layer; (e) After pre-pressing at 2 MPa for 60 s, hot pressing was performed at 5 MPa and 180°C.

5. The preparation process according to claim 4, characterized in that: In the step (c), the phenolic resin adhesive is applied to the mixture in an amount of 10 wt %.

6. The preparation process according to claim 4, characterized in that: The step (a) further includes placing the GFRP particles in an argon plasma treatment device, treating them at a power of 300 W for 5 minutes, and maintaining the pressure of the treatment chamber at 50-80 Pa.

7. The preparation process according to claim 4, characterized in that: In the step (d), a transition layer is inserted between the surface layer and the middle layer. The preparation of the transition layer includes: mixing 2-4 mesh and 4-8 mesh GFRP particles in a ratio of 1:1; paving at a 45° direction, and controlling the layer thickness to be 1.5-2.0 mm.

8. The preparation process according to claim 4, characterized in that: The hot pressing process in step (e) is divided into two stages: the first stage: hot pressing at 2 MPa pressure and 160° C. for 5 minutes; The second stage: increase to 5MPa and hot press at 180℃ for 8 minutes.

9. The preparation process according to claim 4, characterized in that: The glue application adopts a dual-fluid atomizing spray gun, the atomizing pressure is 0.3-0.5MPa, and the adhesive droplet particle size is 50-80μm.

10. The preparation process according to claim 4, characterized in that: The method also includes step (f) of curing the hot-pressed slab in an environment of 20±2°C and a relative humidity of 65±5% for 48 hours; and also includes a mold system and orthogonal paving equipment specifically used for preparing composite materials, wherein the mold system includes a mold body: provided with a layered paving groove and an edge rack to support precise positioning; a hydraulic pre-pressing module: driving the lower support plate through a hydraulic cylinder to achieve a 2MPa pre-pressing, and cooperating with an upper pressing plate assembly with a heating device to complete hot pressing molding; a quick disassembly and assembly design: the snap-on pressing plate assembly cooperates with the limit groove to achieve quick clamping and demoulding of the finished product; the orthogonal paving equipment includes a multi-directional paving mechanism: through a gear-rack transmission linkage directional roller group, cooperating with a rotatable partition bin to achieve longitudinal / lateral / 45° paving direction switching; an unpowered material distribution system: using counter-rotating material distribution rollers to evenly disperse the GFRP-wood mixture, and the atomized adhesive penetrates into the material surface through the gap between the directional rollers; a modular silo: a four-partition rotating silo supports the precise quantitative delivery of surface, middle and core layer materials, with the error controlled within ±2%.

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