A retired fan blade regenerative GFRP reinforced wood-based composite material with a biomimetic gradient structure and a preparation process thereof

Abstract

The application discloses a retired fan blade regenerative GFRP reinforced wood-based composite material with a bionic gradient structure and a preparation process thereof. The composite material comprises a five-layer orthogonal laying structure, and the weight distribution is 1:2:4:2:1 in weight ratio of a surface layer: an intermediate layer: a core layer: an intermediate layer: a surface layer. The surface layer and the core layer adopt a mixture of 2-4 mesh GFRP particles and poplar shavings laid in the longitudinal direction. The preparation process comprises crushing and screening the retired fan blade to obtain three groups of GFRP particles with mesh sizes of 2-4, 4-8 and 8-20; mixing the GFRP particles with the poplar shavings according to the surface layer material, the intermediate layer material and the core layer material; applying a phenolic resin adhesive to the mixed materials; orthogonally laying the mixed materials in a mold; pre-pressing at 2 MPa for 60 s; and hot-pressing molding. The obtained composite material is designed through a five-layer orthogonal bionic gradient structure, and the high-strength characteristic of the regenerative GFRP is retained, excellent mechanical properties, water resistance and interlayer stress coordination capability are realized, and the advantages of stable interface combination and environmental protection regeneration are combined.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material manufacturing, and particularly relates to a retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure and a preparation process thereof. BACKGROUND

[0002] Wood-based composites (WBC) are composite materials prepared by adding polymer, inorganic non-metallic materials and nano materials as reinforcing materials to wood materials as a matrix. The wood-based composites have excellent mechanical properties, aging resistance and flame retardant properties, and are widely used in the fields of building, furniture and packaging. At present, the reinforcing materials commonly used for preparing wood-based composites mainly include fiber (glass fiber, carbon fiber and plant fiber, etc.), particles (plastic particles, metal particles and ceramic particles) and nano materials (nano cellulose, carbon nanotube and nano clay, 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 them is poor, which causes processing difficulties, strict equipment technical requirements, and problems such as excessive voids, poor dispersibility and agglomeration in the material, thereby affecting the overall performance and application range of the composite material. With the increasing demand for high-performance composite materials and the deepening of the green low-carbon environmental protection consciousness, it is still necessary to continue to optimize the preparation method of wood-based composites, so as to improve the material performance and reduce the production energy consumption and pollution.

[0003] The introduction of high-performance reinforcing phases to prepare wood-based composites is an effective way to improve material performance and expand application fields. To meet the green transformation needs of the entire economic and social development chain and reduce dependence on non-renewable resources, researchers have developed a new type of wood-based composite material that uses high-strength, corrosion-resistant recycled glass fiber reinforced polymers (GFRP) from retired wind turbine blades as reinforcing phases and mixes them with wood materials. Relevant cases include: CN117534888A provides a preparation method of wind turbine blade recycling material reinforced wood-plastic composite material and product. After the waste wind turbine blade recycling resin powder obtained by mechanical processing is treated by low-temperature plasma, it is blended with wind turbine blade recycling fiber reinforced polyolefin masterbatch, maleic anhydride grafted polyolefin, wood processing residues, and other additives prepared by the granulation process, and then granulated and extruded to prepare a wood-plastic composite material. 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 recycled glass fiber from wind turbine blades to prepare wood-plastic composites. The 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 then subjected to mixing, hot pressing, and cold pressing to prepare a wood-plastic composite material with strong mechanical properties and weather resistance. Although the invention effectively overcomes the performance deficiencies of wood-plastic composites and reduces the use of plastic, it still cannot achieve complete renewable raw materials and general energy-saving and emission-reducing effects, similar to CN117534888A. CN119458730A discloses the application of retired wind turbine blades in the manufacture of new type of board and manufacturing method. After the retired wind turbine blades are cut and crushed, the glass fiber powder (diameter ≤3mm), epoxy resin powder, PVC / PET powder, and light wood powder in the blades are separated by multi-stage screening. After mixing these components and applying glue, they are subjected to multi-stage sweeping, and finally, they are subjected to hot pressing and cold pressing to obtain a new type of board with high economic value and good waterproofness. Although this method realizes the resource utilization of the components of retired wind turbine blades, the recycling process requires repeated crushing-screening-separation operations, and the process of recycling GFRP is complicated and causes significant damage to the performance of GFRP. At the same time, Zhang et al. pointed out that the surface epoxy resin of GFRP would hinder the formation of a tight interface between GFRP and wood materials, resulting in a weak interface layer in wood-based composites. Therefore, further exploration of the structure regulation strategy and performance optimization technology of GFRP reinforced wood-based composites is still needed to promote the development of material multifunctional integration, and a new type of retired wind turbine blade recycled GFRP reinforced wood-based composite material with a biomimetic gradient structure and its preparation process are urgently needed in the market. SUMMARY

[0004] The application provides a retired fan blade regenerated GFRP reinforced wood-based composite material with a bionic gradient structure and a preparation process thereof, and solves the above technical problems.

[0005] The application provides a retired fan blade regenerated GFRP reinforced wood-based composite material with a bionic gradient structure, which comprises five layers of orthogonal laying structures and has a weight distribution of 1:2:4:2:1 in the proportion of a surface layer-a middle layer-a core layer-a middle layer-a surface layer, wherein the surface layer and the core layer are a mixture of 2-4 mesh GFRP particles and poplar shavings laid in the longitudinal direction.

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

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

[0008] The application provides a preparation process of a retired fan blade regenerated GFRP reinforced wood-based composite material with a bionic gradient structure, which comprises the following steps:

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

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

[0011] (c) applying a phenolic resin adhesive to the mixed material;

[0012] (d) orthogonal laying in a mold in a weight ratio of 1:2:4:2:1 for the surface layer-the middle layer-the core layer-the middle layer-the surface layer;

[0013] (e) hot pressing at 5 MPa and 180 DEG C after pre-pressing at 2 MPa for 60 s.

[0014] Further, the amount of the adhesive applied to the mixed material in step (c) is 10 wt%.

[0015] Further, after step (a), the GFRP particles are placed in an argon plasma treatment device, treated at a power of 300 W for 5 minutes, and the pressure in the treatment chamber is maintained at 50-80 Pa.

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

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

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

[0019] Further, the sizing adopts a double-fluid atomizing spray gun, the atomizing pressure is 0.3-0.5MPa, and the adhesive droplet particle size is 50-80μm.

[0020] Further, it further comprises step (f) of aging the hot-pressed plate blank in an environment of 20±2℃ and relative humidity of 65±5% for 48 hours.

[0021] Further, a mold system specially used for preparing a retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure has a core structure comprising: a mold main body provided with a layered laying groove and an edge rack to support accurate positioning; a hydraulic pre-pressing module that realizes 2MPa pre-pressing through a lower support plate driven by a hydraulic cylinder and completes hot pressing forming in cooperation with an upper pressing plate assembly provided with a heating device; a quick disassembly and assembly design that realizes quick clamping and product demolding through cooperation of a clamping type pressing plate assembly and a limiting groove. The mold integrates the functions of laying, pre-pressing and hot pressing in one, shortens the process flow time, integrates the traditional multiple processes into continuous production, significantly improves the preparation efficiency, shortens the pre-pressing time by 40%, and at the same time, accurately controls the temperature and pressure to ensure the interlayer bonding quality.

[0022] Further, an orthogonal laying device for preparing a retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure has the following technical features: a multidirectional laying mechanism that realizes longitudinal / lateral / 45° laying direction switching through gear-rack transmission linkage directional roller groups in cooperation with a rotatable partition bin; a non-powered material distribution system that uniformly distributes GFRP-wood mixture through counter-rotating distribution rollers, and atomized adhesive penetrates into the material surface through the gap between the directional rollers; a modular material bin that supports accurate quantitative feeding of surface layer, intermediate layer and core layer materials with an error controlled within ±2%. The device does not need external energy driving, accurately constructs the five-layer gradient structure through mechanical linkage, and the laying speed reaches 1.5m 2 / min, the layer thickness uniformity is improved by 30% compared with traditional devices, and is particularly suitable for customized production.

[0023] The retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure and the preparation process thereof have the following beneficial effects:

[0024] 1、The present application simplifies the recycling process, maximizes the retention of the original performance of the recycled material, applies it as a reinforcing material to wood-based composites, and cooperates with the design of biomimetic structures to build high-performance and multi-functional wood-based composites. The present application not only effectively solves the recycling problem of wind turbine blade recycled materials, but also converts industrial waste into high-performance practical resources. It also greatly broadens the performance boundaries of wood-based composites. In terms of material performance improvement, through innovative processes and designs, wood-based composites have high strength, high toughness and multi-functional characteristics, breaking through the bottleneck of traditional materials in mechanical properties and functionality. From the perspective of environmental protection, it reduces the over-reliance on virgin wood and reduces the potential harm of wind turbine blade waste to the environment, contributing 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 furniture manufacturing field, it can produce products that are both aesthetically pleasing and durable, meeting consumers' dual pursuit of quality and environmental protection. In addition, the technical route adopted by the present application is scalable and compatible, can be combined with other emerging material technologies, further promoting the innovative development of material science, and providing ideas and references for the research and development of more high-performance and multi-functional materials in the future;

[0025] 2、Wood-based composites mainly have the following problems: (1) material performance defects (poor weather resistance, low dimensional stability, and limited mechanical properties); (2) processing and technology challenges (interface compatibility problems, high processing energy consumption and cost); (3) market and application defects (insufficient cost competitiveness and scarcity of high-end products); (4) environmental and sustainable development issues (raw material sources), and the five-layer orthogonal laying structure of the present application greatly improves the static bending strength;

[0026] 3、The main problems of the retired wind turbine blade recycled GFRP reinforced wood-based composite material are: (1) performance defects of recycled materials (materials are damaged during recycling); (2) poor interface bonding of composite materials, resulting in low performance (low interface bonding strength); (3) economic and scale challenges (high recycling cost, unstable raw material supply, and limited application scenarios); and the present application through the "gradient structure design-interface reinforcement-scale process" three-in-one technical innovation, makes the recycled GFRP reinforced wood-based composite material in performance, cost and sustainability overall surpasses the existing technology, providing an industrialized solution for wind turbine blade circular economy;

[0027] 4、The application imitates the natural layered structure of the nacre layer, innovatively designs a wood-based composite material with a five-layer structure, and significantly improves the interface bonding strength of the material. Different specifications of retired wind turbine blades are used as reinforcing phase to embed into the poplar flake matrix, and after longitudinal and transverse cross arrangement and paving, a biomimetic gradient wood-based composite material with high strength and toughness and corrosion resistance is obtained by hot pressing. The technology further expands the development potential of wood-based composite materials in sustainable economy and multi-scene application, and provides practical basis for high-value recycling of wind power industry waste;

[0028] 5、The mold system and orthogonal paving equipment for preparing the retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure form a closed production unit, which integrates the traditional 8 processes into 3 continuous operations, greatly reduces the production line area, and through the precise control of hydraulic pre-pressing (2 MPa) and gradient hot pressing, the interlaminar bonding strength of the reinforced composite material is enhanced, the performance of the composite material is improved, and the material utilization rate reaches 98.5% due to the paving precision of the equipment, which is conducive to realizing carbon emission reduction in cooperation with the regenerated technology of retired materials. The technical system successfully solves the problems of poor equipment adaptability and complex process in the industrialization of the regenerated GFRP reinforced wood-based composite material, and provides a complete equipment solution for the large-scale application of green building materials. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a mechanism diagram of the retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure prepared in embodiment 1 of the application;

[0030] Figure 2 It is a corrosion resistance performance diagram of the retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure prepared in embodiment 1 of the application;

[0031] Figure 3 It is a mold structure diagram of embodiment 1 of the application Figure 1 ;

[0032] Figure 4 It is a mold structure diagram of embodiment 1 of the application Figure 2 ;

[0033] Figure 5 It is a mold structure diagram of embodiment 1 of the application Figure 3 ;

[0034] Figure 6 It is a paving equipment structure diagram of embodiment 1 of the application Figure 1 ;

[0035] Figure 7 It is a paving equipment structure diagram of embodiment 1 of the application Figure 2 ;

[0036] Figure 8 Structure diagram of paving equipment of embodiment 1 of the present application Figure 3 ;

[0037] Figure 9 Structure diagram of paving equipment of embodiment 1 of the present application Figure 4 ;

[0038] Marking in the figure:

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

[0040] The present application will be described in greater detail by way of specific embodiments, from which the skilled person will readily appreciate other advantages and functionalities of the present application. The present application can also be carried out or applied in other different embodiments, and the details in the present specification can be modified or changed in various ways based on different views and applications without departing from the spirit of the present application.

[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 commercially available unless otherwise specified.

[0042] Unless otherwise specified, all reagents are used as received without further purification.

[0043] In the preparation examples and embodiments of the present application, the "parts" are weight parts unless otherwise specified, and the concentration percentages are weight concentrations unless otherwise specified.

[0044] Example 1

[0045] In step (1), the GFRP used is cut and broken from retired wind turbine blades, and then sieved through different mesh screens to obtain three types of specifications of 2-4 mesh, 4-8 mesh and 8-20 mesh.

[0046] Step (2), different specifications of GFRP (2-4 mesh, 4-8 mesh, 8-20 mesh) were used as reinforcing materials, and mixed with poplar shavings in a weight ratio of 3:7. The mixture of 2-4 mesh GFRP and shavings was used as the surface layer material, the mixture of 4-8 mesh GFRP and shavings was used as the intermediate layer material, and the mixture of 8-20 mesh GFRP and shavings was used as the core layer material;

[0047] Step (3), phenolic resin 85 was used as adhesive, and the adhesive amount was 10%. The surface layer material, the intermediate layer material and the core layer material were glued respectively. A double-fluid atomizing spray gun was used, the atomizing pressure was 0.3-0.5 MPa, the adhesive droplet size was 50-80 μm, and the poplar shavings were sprayed with phenolic resin adhesive for mixing. After 10 minutes of sufficient stirring, the shavings with uniform glue were obtained.

[0048] Step (4), the shavings with glue were filled into a 300×300×12mm mold using a laying equipment. The material structure was 5 layers, and the weight of the surface layer, the intermediate layer, the core layer, the intermediate layer and the surface layer was distributed according to the ratio of 1:2:4:2:1. The adjacent layers were orthogonally laid, that is, the laying direction of the shavings in the upper and lower surface layers and the core layer was consistent, which was longitudinal, and the laying direction of the shavings in the intermediate layer was transverse.

[0049] Step (5), the laying equipment was removed from the mold, and the upper pressing plate assembly was installed on the mold. The upper pressing plate assembly was pressed on the laid board blank, and the lower support plate 7 was driven upward by the hydraulic telescopic cylinder 5 to press the board blank. The pre-pressing pressure was 2 MPa, and the time was 60 s. The board blank had a certain density and initial bonding strength, and the forming weight of the board blank was improved.

[0050] Step (6), the heating device 8 at the lower end of the lower support plate 7 was started, and the board blank was hot-pressed at a hot-pressing pressure of 5 MPa and a temperature of 180℃ for 13 min. A composite material with a preset density of 850 kg / m 3 , and a size of 300×300×12mm was obtained.

[0051] Step (7), after hot-pressing of the board blank, the board blank was cooled and aged in an environment of 20±2℃ and a relative humidity of 65±5% for 2 days. The purpose of eliminating the stress generated in the material processing process, improving the dimensional stability and balancing the moisture content was achieved. Finally, a retired wind turbine blade regenerated GFRP reinforced wood-based composite material with a biomimetic gradient structure was obtained.

[0052] Example 2

[0053] The difference from example 1 is that a plasma activation treatment is added after step (1). The obtained sieved GFRP particles are placed in a plasma treatment equipment, and treated in an argon atmosphere at a power of 300 W for 5 minutes. The surface oxygen element content is 28-32 at%, and a nano-gully 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 intermediate layer. The transition layer is made of 2-4 mesh and 4-8 mesh GFRP mixed in a 1:1 ratio, and the shavings paving direction of the transition layer is at a 45° angle to the adjacent layer.

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

[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 everything else is the same as in 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 everything else is the same as in 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 everything else is the same as in 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) automotive parts; otherwise, it is the same as Example 1.

[0064] Example 7

[0065] like Figures 3-9 As shown, the mold includes a mold body 1, a mold groove in the middle of the mold body 1, edge grooves 2 on the four sides of the mold body 1, a toothed rack 3 in the edge groove 2, and a limiting groove 4 on the mold body 1.

[0066] A hydraulic telescopic cylinder 5 is fixed at the bottom of the mold body 1. 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. A heating device 8 is installed at the lower end of the lower support plate 7.

[0067] The upper pressure plate assembly includes an upper pressure plate 9, which presses against the upper end of the blank in the mold groove. Support columns 10 are provided at the four corners of the upper pressure plate 9. One end of the support column 10 is rotatably connected to the snap-fit ​​block 11, and the other end of the snap-fit ​​block 11 is snapped into the limiting groove 4. The upper pressure plate 9 is provided with a pull column 12 and a reinforcing rib 13.

[0068] The working principle of the above technical solution is as follows: Adhesive-coated wood shavings are filled into the mold groove of the mold using a paving device. The lower surface of the slab after paving contacts the lower support plate 7. The paving device is removed from the mold, and the upper pressure plate 9 is pressed onto the upper end of the slab in the mold groove. The locking blocks 11 at the four corners of the upper pressure plate 9 are rotated, causing the locking blocks 11 and the support column 10 to rotate. The front end of the support column 10 engages with the limiting groove 4. The hydraulic telescopic cylinder 5 is activated, causing the lower support plate 7 to move upward, thereby shortening the distance between the lower support plate 7 and the upper pressure plate 9. The distance is used to apply pressure to the slab, giving it a certain density and initial bonding strength, thus increasing the slab's forming weight. The heating device 8 is activated to hot-press the slab. After hot pressing, the front end of the support column 10 is separated from the limiting groove 4, and the pull column 12 is pulled up to pull the upper pressure plate assembly out of the mold. The hydraulic telescopic cylinder 5 is activated again to drive the lower support plate 7, lifting the composite material for easy removal. Laying, cold pressing, and hot pressing are all completed within the mold groove, which is convenient and quick, greatly reducing process time and equipment costs.

[0069] Example 8

[0070] like Figures 3-9 As shown, the paving equipment includes a housing 14, which is slidably connected to the upper end of the mold body 1. A gear 15 is rotatably connected to the side of the housing 14, and the gear 15 meshes with the gear 2 18 for transmission. Multiple directional rollers 19 are rotatably connected inside the housing 14. The gear 2 18 is fixedly connected to the directional rollers 19 at the edge position. Adjacent directional rollers 19 are connected by a belt 20 for transmission. A baffle 21 and a triangular guide plate 22 are fixed inside the housing 14. The directional rollers 19 at the edge position are connected to the material distribution rollers 24 through a belt 2 23 for transmission. Two material distribution rollers 24 are connected by gear meshing for transmission.

[0071] A central rotating rod 26 is rotatably connected inside the outer shell 14. A knob 25 is fixedly connected to the end of the central rotating rod 26. Four partitions 30 are fixedly connected to the central rotating rod 26. A feed inlet 27 is provided at the upper end of the outer shell 14.

[0072] A handrail 28 is fixed to the side of the outer shell 14, a protective buckle plate 29 is provided on the outer side of the outer shell 14, the outer shell 14 is slidably connected to the limiting post 16, a spring 17 is provided between the outer shell 14 and the limiting post 16, and the front end of the limiting post 16 is engaged in the limiting 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 one 15 is engaged with the gear rack 3 in the edge groove 2, and the front end of the limiting column 16 is clamped into the limiting groove 4 under the pulling force of the spring 17.

[0074] The adjacent two partitions 30 form a containing groove, and the center rotating rod 26 is provided with four containing grooves. The preset weight of the surface layer of the shaving material is added from the feeding port 27, the surface layer of the shaving material falls into the first containing groove, the rotating knob 25 is rotated to drive the center rotating rod 26 to rotate, and the four partitions 30 are driven to rotate with the center rotating rod 26. The preset weight of the middle layer of the shaving material is added into the second containing groove, the rotating knob 25 is rotated again to add the preset weight of the core layer of the shaving material into the third containing groove. At this time, the first containing groove is rotated downward, and the surface layer of the shaving material falls between the two distribution rods 24.

[0075] The hand-held rod 28 is pushed forward to drive the shell 14 to slide forward on the mold body 1, the gear one 15 is engaged with the gear rack 3 to drive the gear one 15 to rotate, the gear two 18 is driven to rotate, the directional rod 19 is driven to rotate, the plurality of directional rods 19 are driven to rotate simultaneously through the belt one 20, the directional rod 19 at the edge position is driven to rotate through the belt two 23, the other distribution rod 24 is driven to rotate through the gear, and the two distribution rods 24 rotate in opposite directions to scatter and fall the surface layer material in the first containing groove. The falling surface layer of the shaving material is guided by the triangular material guiding plate 22, and the surface layer of the shaving material falls between the blades of the directional rod 19. With the rotation of the directional rod 19, the surface layer of the shaving material falls along the edge of the blade of the directional rod 19, and the distributed surface layer of the shaving material is perpendicular to the movement direction of the paving equipment, which is longitudinal paving.

[0076] The paving equipment is lifted and rotated by 90 degrees, so that the two ends of the shell 14 of the paving equipment abut against the limiting grooves 4 on the other two sides of the mold body 1, and the paving direction is changed. The rotating knob 25 is rotated to drive the center rotating rod 26 to rotate, the second containing groove storing the middle layer of the shaving material is rotated downward, the preset weight of the middle layer of the shaving material is added into the fourth containing groove from the feeding port 27, and the hand-held rod 28 is pushed forward to drive the shell 14 to slide forward on the mold body 1. The middle layer of the shaving material is paved on the surface layer of the shaving material, and the paving direction of the middle layer of the shaving material is opposite to that of the surface layer of the shaving material, which is transverse paving. The above operation is repeated to realize the paving of the remaining layers, and the paving direction is controllable. Compared with manual paving, the paving is more uniform, does not need power supply, can be operated anytime and anywhere, is convenient and fast, and greatly shortens the paving time.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that in step (2) the equal weight parts of GFRP are mixed with poplar shavings, and the others 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 reinforcing material mixed with poplar shavings, and the others 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 reinforcing material mixed with poplar shavings, and the others are 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 reinforcing material mixed with poplar shavings, and the others are the same.

[0085] Performance Test

[0086] 1. The composite materials prepared in the examples and comparative examples are tested for static bending strength, elastic modulus, internal bonding strength and water absorption thickness swelling rate, the static bending strength test refers to ISO 16978, the elastic modulus refers to ASTM D1037, the internal bonding strength test refers to ISO 16983, and the water absorption thickness swelling rate test refers to ISO 16979, and 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 to Comparative Examples 2-4 (single particle size reinforcement), which proves that the biomimetic gradient design significantly improves the interlayer stress distribution; the plasma activation treatment of Example 2 can improve the interfacial bonding strength of GFRP and phenol, improve the internal bonding strength, and reduce the water absorption rate; the introduction of the transition layer structure and the segmented hot pressing process eliminates the interlayer shear stress concentration, and improves the static bending strength.

[0090] 2. Anticorrosion performance test: Pure wood substrate (size: 20x20x5mm) without any anticorrosion treatment was set as the blank group, the retired wind turbine blade regenerated wood-based composite (Wood-Based Composite, WBC) without GFRP reinforcement was set as the WBC group, and Example 1 was set as the GFRP@WBC group. By simulating microbial corrosion in a natural environment, the antibacterial properties and corrosion resistance of different materials under the same conditions were compared to verify the role of the biomimetic gradient structure of the GFRP reinforced wood-based composite in improving the anticorrosion performance. A mixed bacterial suspension (Trametes versicolor, Aspergillus niger, and Penicillium) was evenly sprayed into a petri dish, and the three groups of samples were placed on the surface of the bacterial-containing medium (medium composition: potato glucose agar, pH 5.6) in a constant temperature and humidity chamber at a temperature of 28°C and a humidity of 85%. After 14 days of incubation, the colony growth area, color change, and material surface corrosion were recorded, such as the appearance of spots and cracks.

[0091] From Figure 2 It can be seen that the blank group phenomenon is that the surface of the medium is covered with uniform white mycelium (as shown on the left), and the wood surface is severely corroded with obvious holes and softening. Therefore, the wood without anticorrosion treatment provides sufficient nutrients for microorganisms, leading to rapid reproduction and material degradation. The WBC group phenomenon is that the grayish white wood-based composite material surface appears scattered yellowish colony spots, and the corrosion area accounts for about 35%. Therefore, the retired wind turbine blade regenerated material (WBC) has a higher porosity, and some areas are invaded by mold, but the anticorrosion performance is better than that of the blank group. The GFRP@WBC group phenomenon is that the surface of the dark brown square composite material has no visible colonies, and only the edge of the medium has slight mycelium growth. Therefore, there are no corrosion marks on the contact surface of the material and the medium, and the biomimetic gradient layer blocks the penetration of microorganisms, 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-based layer effectively inhibits the adhesion and diffusion of microorganisms.

[0092] The specific embodiments of the present application are described in detail above, but they are only examples, and the present application is not limited to the specific embodiments described above. Any equivalent modifications and alternatives to the present application made by those skilled in the art are also within the scope of the present application. Therefore, equivalent transformations and modifications made without departing from the spirit and scope of the present application should be included in the scope of the present application.

Claims

1. A decommissioned wind turbine blade regenerated GFRP reinforced wood-based composite with biomimetic gradient structure, characterized in that, The composite material is a five-layer orthogonal paving structure composed of surface layer-middle layer-core layer-middle layer-surface layer, and the weight ratio of surface layer-middle layer-core layer-middle layer-surface layer is 1:2:4:2:1, wherein the surface layer adopts a mixture of 2-4 mesh GFRP particles and poplar shavings paved longitudinally, the middle layer adopts a mixture of 4-8 mesh GFRP particles and poplar shavings paved transversely, and the core layer adopts a mixture of 8-20 mesh GFRP particles and poplar shavings paved longitudinally; the weight ratio of the mixture of GFRP particles and poplar shavings is 3:

7.

2. The process for the preparation of a composite material according to claim 1, characterized in that, The method comprises the following steps: (a) crushing and screening the retired wind turbine blade to obtain three groups of GFRP particles with mesh sizes of 2-4, 4-8 and 8-20; (b) mixing GFRP and poplar shavings in a weight ratio of 3:7 for surface layer material, middle layer material and core layer material respectively; (c) applying phenolic resin adhesive to the mixed material; (d) orthogonal paving in a mold according to a weight ratio of 1:2:4:2:1 for surface layer-middle layer-core layer-middle layer-surface layer; (e) hot pressing at 5 MPa and 180 DEG C after pre-pressing at 2 MPa for 60 seconds.

3. The manufacturing process of claim 2, wherein, The amount of adhesive applied to the mixed material in step (c) is 10 wt%.

4. The manufacturing process of claim 2, wherein, After step (a), the GFRP particles are further placed in an argon plasma treatment device, treated at a power of 300 W for 5 minutes, and the pressure in the treatment chamber is maintained at 50-80 Pa.

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

6. The manufacturing process of claim 2, wherein, The hot pressing process of step (e) is divided into two stages: first stage: hot pressing at 2 MPa and 160 DEG C for 5 minutes; Second stage: hot pressing at 5 MPa and 180 DEG C for 8 minutes.

7. The manufacturing process of claim 2, wherein, The adhesive is applied by a two-fluid atomizing spray gun, the atomizing pressure is 0.3-0.5 MPa, and the adhesive droplet size is 50-80 μm.

8. The manufacturing process of claim 2, wherein, Further comprising step (f) aging the hot-pressed plate blank in an environment of 20±2 DEG C and relative humidity of 65±5% for 48 hours; the preparation process uses a mold system and orthogonal paving equipment specially designed for preparing composite materials, the mold system comprises a mold main body provided with a layered paving groove and an edge rack to support accurate positioning; a hydraulic pre-pressing module: the lower support plate is driven by a hydraulic cylinder to realize 2 MPa pre-pressing, and the upper pressing plate assembly with a heating device is used to complete hot pressing; quick disassembly and assembly design: the clamping type pressing plate assembly is matched with the limiting groove to realize quick clamping and product demolding; the orthogonal paving equipment comprises a multidirectional paving mechanism: the geared rack transmission linkage directional roller group is matched with the rotatable partition bin to realize longitudinal / transverse / 45° paving direction switching; a non-powered material distribution system: the GFRP particles and poplar shavings mixture is uniformly dispersed by the counter-rotating distribution rollers, and the atomized adhesive penetrates into the material surface through the gap between the directional rollers; a modular material bin: the four-part rotating material bin supports accurate quantitative feeding of surface layer, middle layer and core layer materials, and the error is controlled within ±2%.

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