A fiber composite material, its preparation method and application, and composite sand-fixing barriers.

Abstract

This invention belongs to the field of sand control and stabilization technology, specifically relating to a fiber composite material, its preparation method and application, and composite sand-fixing barriers. The fiber composite material provided by this invention comprises the following raw materials in weight percentages: 55-80% modified fiber, 10-20% flexibility agent, 5-10% fertilizer slow-release agent, and 5-15% adhesive; the modified fiber includes natural fiber and silane-based interface modifiers grafted onto the surface of the natural fiber. The main raw materials used in this invention are natural materials such as wood fiber, bamboo fiber, and hemp fiber. These fibers can be obtained by hot grinding wood branches, waste materials, and recycled materials, greatly reducing the barrier to obtaining raw materials. The composite material can be used to prepare sand barriers, which decompose into organic matter, carbon dioxide, and water under the action of microorganisms in the soil. Simultaneously, the degradation of organic matter and the fertilizer slow-release agent have a good effect on the protection of sand dunes and the growth of plants, without causing environmental pollution.

Description

Technical Field

[0001] This invention belongs to the field of sand control and stabilization technology, specifically relating to a fiber composite material, its preparation method and application, and a composite sand-stabilizing barrier. Background Technology

[0002] Sand stabilization is the most important aspect of sand control and desertification prevention projects. Currently, the main method for sand control and stabilization is the construction of sand barriers. Mechanical sand barriers refer to various forms of obstructions set up on the sand surface using materials such as firewood, grass, branches, clay, and pebbles. Their purpose is to control the direction, speed, and structure of wind and sand movement, change wind erosion, prevent wind erosion, and alter the wind's effect and micro-topography. Traditional sand barriers mainly consist of willow sand barriers and straw sand barriers. However, the supply of traditional willow branches is insufficient in a short period, causing price increases and affecting the progress and cost of project implementation. Straw sand barriers, made from materials such as rice straw, wheat straw, or reed stalks, are easily perishable, resulting in a short service life and insufficient sand stabilization effect, failing to effectively block the movement of wind and sand.

[0003] With the development of science and technology, some new materials for making sand barriers have emerged, such as nylon mesh sand barriers and high-density polyethylene (HDPE) panel sand barriers. However, the non-biodegradability of these materials has also caused some secondary pollution.

[0004] Furthermore, vegetation-based sand fixation is a major technology for current sand control and desertification prevention, and it is often combined with sand barrier sand fixation. Vegetation-based sand fixation not only uses the growth process of plants to stabilize the sand, but also reduces wind speed in sandy areas. However, many geological conditions currently do not allow for the planting of psammophytic plants. Even if plants are planted, they often lack sufficient nutrients and fertilizers, resulting in low emergence and survival rates, making the combined use of vegetation and sand barrier sand fixation ineffective. Therefore, providing an environmentally friendly, biodegradable, low-cost, and industrially scalable sand barrier material is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] In view of this, the present invention provides a fiber composite material, its preparation method and application, and a composite sand-fixing barrier. The fiber composite material provided by the present invention uses natural fibers as raw materials to improve the environmental friendliness and biodegradability of the material while reducing production costs; at the same time, the fertilizer corrosion inhibitor is slowly released during the material degradation process, which can effectively improve the survival rate of plants planted inside the sand barrier.

[0006] To address the aforementioned technical problems, the present invention provides a fiber composite material comprising the following raw materials in weight percentages:

[0007] Modified fibers 55-80%;

[0008] 10-20% flexibility agent;

[0009] Fertilizer slow-release agent 5-10%;

[0010] Adhesive 5~15%;

[0011] The modified fiber comprises natural fiber and a silane-based interface modifier grafted onto the surface of the natural fiber.

[0012] Preferably, the natural fiber includes one or more of wood fiber, bamboo fiber, hemp fiber and seaweed fiber; the length of the natural fiber is less than or equal to 500 μm and the diameter of the natural fiber is less than or equal to 250 μm.

[0013] The silane-based interface modifiers include one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, 1H,1H,2H,2H perfluorodecyltrichlorosilane, 1H,1H,2H,2H perfluorooctyltrichlorosilane, and 1H,1H,2H,2H perfluorodecyltriethoxysilane.

[0014] Preferably, the flexibility agent includes polyurethane particles, polyurethane fibers, polypropylene fibers, or polyester fibers.

[0015] Preferably, the adhesive includes one or more of urea-formaldehyde resin adhesive, phenolic resin adhesive, melamine-modified urea-formaldehyde resin adhesive, epoxy resin adhesive, and isocyanate adhesive.

[0016] Preferably, the fertilizer slow-release agent includes one or more of sulfur-coated urea, urea-formaldehyde, isobutylene diurea, oxamide fertilizer, nitrulase inhibitor fertilizer, and resin-coated urea.

[0017] The present invention also provides a method for preparing the fiber composite material described in the above technical solution, comprising the following steps:

[0018] Natural fibers and silane-based interface modifiers are first mixed and then dehydrated to obtain modified fibers;

[0019] After the adhesive is atomized and sprayed onto the surface of the modified fiber, it is mixed with a flexibility agent and a fertilizer slow-release agent to obtain a mixture.

[0020] The mixture is shaped and then hot-pressed to obtain the fiber composite material.

[0021] Preferably, the temperature of the dehydration reaction is 50~150℃, and the time of the dehydration reaction is 30~150min;

[0022] The atomization pressure is 1~10MPa;

[0023] The thickness of the formed blank is 3~50cm;

[0024] The hot pressing temperature is 100~180℃, and the hot pressing holding time is 0.5~5min.

[0025] The present invention also provides the application of the fiber composite material described in the above technical solution or the fiber composite material prepared by the preparation method described in the above technical solution in the preparation of sand barriers.

[0026] The present invention also provides a composite sand-fixing barrier, comprising a sand barrier and psammophytic plants;

[0027] The material used for the sand barrier is the fiber composite material described in the above technical solution or the fiber composite material prepared by the preparation method described in the above technical solution.

[0028] Preferably, the desert plants include one or more of Haloxylon ammodendron, Nitraria tangutorum, Caragana korshinskii, Caragana sinica, Calligonum mongolicum, and Artemisia scoparia;

[0029] The sand barriers can take the form of strips, squares, or arcs;

[0030] When the sand barrier is in the form of strips, the psammophytic plants are planted in the areas between adjacent strips;

[0031] When the sand barrier is in the form of a grid, the psammophytic plants are planted in the middle area of ​​the grid of the sand barrier;

[0032] When the sand barrier is in the form of an arc, the desert plants are planted in the area between adjacent arcs.

[0033] This invention provides a fiber composite material comprising the following raw materials in weight percentages: 55-80% modified fiber, 10-20% flexibility agent, 5-10% fertilizer slow-release agent, and 5-15% adhesive; the modified fiber includes natural fiber and silane-based interface modifier grafted onto the surface of the natural fiber. The main raw materials used in this invention are natural materials such as wood fiber, bamboo fiber, and hemp fiber. These fibers can be obtained by thermally grinding wood branches, waste materials, and recycled materials, greatly reducing the barrier to obtaining raw materials. The composite material can be used to prepare sand barriers. After use, the sand barriers decompose into organic matter, carbon dioxide, and water under the action of microorganisms in the soil, which has a good effect on the protection of sand dunes and the growth of plants, and does not pollute the environment.

[0034] This invention adds a flexibility agent during the preparation of fiber composite materials, giving the composite material the flexibility to sway with the wind and sand, thereby reducing wind speed and trapping sand. Compared with other traditional plate-type sand barriers (such as high-density polyethylene plates), the sand barrier of this invention is well matched to the wind and sand environment of desert.

[0035] This invention adds a fertilizer slow-release agent to fiber composite materials, which can be slowly released during the subsequent degradation of the composite materials, promoting the growth of psammophyte seeds and psammophyte plants, and further promoting the combination of mechanical sand fixation and plant sand fixation. This solves the bottleneck that current mechanical sand fixation and plant sand fixation cannot be effectively used in synergy. The composite sand barrier can increase the roughness of the ground surface and slow down the flow speed of air close to the ground surface, thereby reducing the scale and degree of wind erosion. By utilizing the windbreak, sand fixation, water interception, and fertilizer slow-release effects of the sand barrier, it further promotes seed growth and development, and further plays a role in windbreak and sand fixation.

[0036] The fiber composite material provided by this invention is significantly different from that used for sand willow barriers. Although sand willow barriers degrade, rot, and decay under the action of microorganisms as their service life increases, the degradation process is uncontrollable. In contrast, this invention uses an adhesive to bond natural fibers together, and the degradation and aging pattern of the fiber composite material can be changed by adjusting the amount of adhesive used. This makes it suitable for areas with different wind and sand environments, thus expanding the application range of mechanical sand-fixing materials.

[0037] Using straw, rice straw, and willow as sand barrier materials means that the size can only be determined by the specifications of the raw materials, and cannot be adjusted according to actual needs. Moreover, straw and rice straw have the disadvantage of not being able to retain long dimensions during mechanical harvesting. The fiber composite material provided by this invention is an industrially mass-producible material with customizable size and adjustable specifications. When using it as a raw material to prepare sand barriers, the construction speed is fast, the construction labor intensity is low, and the project cost is low, which greatly improves the application range and efficiency of fiber composite materials. Attached Figure Description

[0038] Figure 1 for Figure 1 This is a physical image of the clamp (fixing device) used in the embodiment;

[0039] Figure 2 A photograph of the strip-shaped sand barrier (before planting) prepared in Example 1;

[0040] Figure 3 This is a physical image of how the overlapping plates are fixed using a clamp (fixing device) in Example 1;

[0041] Figure 4 A physical image of the composite sand-fixing barrier prepared in Example 1 (including planted vegetation);

[0042] Figure 5 A photograph of the checkered sand barrier (before planting) prepared in Example 3;

[0043] Figure 6 This is a physical image of how the grid-shaped sand barrier is fixed using clamps (fixing devices) in Example 3;

[0044] Figure 7 A physical image of the composite sand-fixing barrier prepared in Example 3 (including planted vegetation);

[0045] Figure 8 This is a physical image of the arc-shaped sand barrier in Example 5;

[0046] Figure 9 The image shows a physical example of the straw checkerboard sand barrier from Comparative Example 1.

[0047] Figure 10 A photograph of the composite sand barrier set up in Example 1 after six months of use;

[0048] Figure 11 A photograph of the composite sand barrier set up in Example 3 after six months of use;

[0049] Figure 12 A photograph of the straw checkerboard sand barrier set up for Comparative Example 1 after six months of use. Detailed Implementation

[0050] This invention provides a fiber composite material comprising the following raw materials in weight percentages:

[0051] Modified fibers 55-80%;

[0052] 10-20% flexibility agent;

[0053] Fertilizer slow-release agent 5-10%;

[0054] Adhesive 5~15%;

[0055] The modified fiber comprises natural fiber and a silane-based interface modifier grafted onto the surface of the natural fiber.

[0056] The raw materials for preparing the fiber composite material provided by this invention, by weight percentage, include 55-80% modified fiber, specifically 55%, 60%, 65%, 70%, 75%, or 80%. In this invention, the modified fiber includes natural fiber and a silane-based interface modifier grafted onto the surface of the natural fiber. As a specific embodiment of this invention, the natural fiber may include one or more of wood fiber, bamboo fiber, hemp fiber, and seaweed fiber, specifically wood fiber, bamboo fiber, hemp fiber, or seaweed fiber; the tree species of the wood fiber may be one or more of balsa wood, paulownia, fir, poplar, ash, and pine, specifically balsa wood, paulownia, fir, poplar, ash, or pine; the bamboo species of the bamboo fiber may be one or more of moso bamboo, bamboo fern, green bamboo, and nan bamboo, specifically moso bamboo, bamboo fern, green bamboo, or nan bamboo. In this invention, bamboo fiber has better flexibility than wood fiber. Using bamboo fiber to prepare composite materials can improve the flexibility of composite materials (boards), increase the ability to swing with the wind, increase the amplitude of board shaking, and have a better effect on windproofing and sand fixation.

[0057] In one specific embodiment of the present invention, the length of the natural fiber can be less than or equal to 500 μm, or can be 50~300 μm, 200~400 μm, 200~500 μm, or 300~500 μm; the diameter of the natural fiber can be less than or equal to 250 μm, or can be 20~150 μm, 50~200 μm, or 150~250 μm. The present invention uses natural fiber as the main raw material, which facilitates the degradation of fiber composite materials, improves their environmental friendliness, and also provides carbon sequestration performance.

[0058] As a specific embodiment of the present invention, the silane-based interface modifier includes one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, 1H,1H,2H,2H perfluorodecyltrichlorosilane, 1H,1H,2H,2H perfluorooctyltrichlorosilane, and 1H,1H,2H,2H perfluorodecyltriethoxysilane, specifically γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, 1H,1H,2H,2H perfluorodecyltrichlorosilane, 1H,1H,2H,2H perfluorooctyltrichlorosilane, or 1H,1H,2H,2H perfluorodecyltriethoxysilane.

[0059] As a specific embodiment of the present invention, the mass percentage of silane interface modifier in the modified fiber can be less than or equal to 5%, specifically 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 2.5%, 3.5% and 5%.

[0060] The raw materials for preparing the fiber composite material provided by the present invention, by weight percentage, include 10-20% flexibility agent, specifically 10%, 13%, 15%, 18%, or 20%. In one specific embodiment of the present invention, the flexibility agent may include polyurethane particles, polyurethane fibers, polypropylene fibers, or polyester fibers. The average particle size of the polyurethane particles may be 5-5000 μm, 5-300 μm, or 300-5000 μm; the average particle size of the polyurethane particles may specifically be 50 μm, 100 μm, or 500 μm; the length of the polyurethane fibers, polypropylene fibers, and polyester fibers may be independently 1 mm to 10 cm, and the linear density may be independently 1.0 to 2.5 dtex.

[0061] The raw materials for preparing the fiber composite material provided by this invention, by weight percentage, include 5-10% fertilizer slow-release agent, specifically 5%, 6%, 8%, or 10%. As a specific embodiment of this invention, the fertilizer slow-release agent may include one or more of sulfur-coated urea, urea-formaldehyde, isobutylene diurea, oxamide fertilizer, nitrifying ureaase inhibitor fertilizer, and resin-coated urea, specifically sulfur-coated urea, urea-formaldehyde, isobutylene diurea, oxamide fertilizer, nitrifying ureaase inhibitor fertilizer, or resin-coated urea.

[0062] The raw materials for preparing the fiber composite material provided by this invention, by weight percentage, include 5-15% adhesive, specifically 5%, 8%, 10%, 13%, or 15%. As a specific embodiment of this invention, the adhesive may include one or more of urea-formaldehyde resin adhesive, phenolic resin adhesive, melamine-modified urea-formaldehyde resin adhesive, epoxy resin adhesive, and isocyanate adhesive, specifically urea-formaldehyde resin adhesive, phenolic resin adhesive, melamine-modified urea-formaldehyde resin adhesive, epoxy resin adhesive, or isocyanate adhesive.

[0063] In one specific embodiment of the present invention, the thickness of the fiber composite material can be less than or equal to 20 mm, or it can be 2.5 to 15 mm.

[0064] The present invention also provides a method for preparing the fiber composite material described in the above technical solution, comprising the following steps:

[0065] Natural fibers and silane-based interface modifiers are first mixed and then dehydrated to obtain modified fibers;

[0066] After the adhesive is atomized and sprayed onto the surface of the modified fiber, it is mixed with a flexibility agent and a fertilizer slow-release agent to obtain a mixture.

[0067] The mixture is shaped and then hot-pressed to obtain the fiber composite material.

[0068] This invention involves a first mixing of natural fibers and a silane-based interface modifier, followed by a dehydration reaction to obtain modified fibers. In one specific embodiment, the mass ratio of the total mass of the natural fibers and the silane-based interface modifier to the mass of the silane-based interface modifier can be 100:0.5 to 5, specifically 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, or 100:5. The first mixing can be achieved by spraying the silane-based interface modifier onto the surface of the natural fibers. This invention does not have specific requirements for the spraying method; conventional methods in the art are acceptable. In one specific embodiment of the present invention, the temperature of the dehydration reaction can be 50~150℃, specifically 50℃, 80℃, 100℃, 120℃ or 150℃; the time of the dehydration reaction can be 30~150min, specifically 30min, 50min, 80min, 100min, 120min, 130min or 150min.

[0069] In this invention, the Si-OH on the surface of the silane-based interface modifier reacts with the -OH on the surface of the natural fiber at high temperature to form Si-OC bonds. After modification, the surface of the natural fiber is linked to the hydrophobic functional groups of the silane-based interface modifier through chemical bonds, which improves the hydrophobic properties of the natural fiber and prevents it from softening and breaking when exposed to rain in the desert.

[0070] After obtaining the modified fibers, the present invention atomizes the adhesive and sprays it onto the surface of the modified fibers, then mixes it with a flexibility agent and a fertilizer slow-release agent to obtain a mixture. In one specific embodiment of the present invention, the atomization pressure can be 1~10 MPa, specifically 1 MPa, 3 MPa, 5 MPa, 8 MPa, or 10 MPa. The present invention's atomization and spraying of the adhesive onto the surface of the modified fibers can improve the uniformity of adhesive dispersion, ensuring the adhesive is evenly sprayed onto the fiber surface, which is beneficial for improving interfacial adhesion performance and reducing the amount of adhesive used.

[0071] The present invention has no special requirements for the second mixing method, as long as it can be mixed evenly.

[0072] After obtaining the mixture, the present invention heat-presses the mixture after molding to obtain the fiber composite material. In one specific embodiment of the present invention, the molding can be performed by laying the mixture using a fiber laying machine to obtain a blank; the thickness of the blank can be 3-50 cm, 5-40 cm, or even 10-30 cm.

[0073] In one specific embodiment of the present invention, the hot pressing temperature can be 100~180℃, specifically 100℃, 120℃, 140℃, 150℃, 160℃ or 180℃; the holding time of the hot pressing can be 0.5~5min, specifically 0.5min, 1min, 2min, 3min, 4min or 5min.

[0074] The present invention also provides the application of the fiber composite material described in the above technical solution or the fiber composite material prepared by the preparation method described in the above technical solution in the preparation of sand barriers.

[0075] The present invention also provides a composite sand-fixing barrier, comprising a sand barrier and psammophytic plants;

[0076] The material used for the sand barrier is the fiber composite material described in the above technical solution or the fiber composite material prepared by the preparation method described in the above technical solution.

[0077] As a specific embodiment of the present invention, the desert plants may include one or more of Haloxylon ammodendron, Nitraria tangutorum, Caragana korshinskii, Caragana chinensis, Calligonum mongolicum, and Artemisia scoparia, specifically Haloxylon ammodendron, Nitraria tangutorum, Caragana korshinskii, Caragana chinensis, Calligonum mongolicum, or Artemisia scoparia; the desert plants can grow into desert plants by sowing desert plant seeds.

[0078] In one specific embodiment of the present invention, the sand barrier may be in the form of strips, squares, or arcs. When the sand barrier is strip-shaped, the desert plants are planted in the intervals between adjacent strips, or desert plant seeds are sown along the board barrier. When the sand barrier is square-shaped, the desert plants are planted in the middle area of ​​the square grid, or desert plant seeds are sown along the board barrier. When the sand barrier is arc-shaped, the desert plants are planted in the intervals between adjacent arc strips.

[0079] In one specific embodiment of the present invention, when the sand barrier is a strip-type sand barrier, the preparation method of the sand barrier may include the following steps:

[0080] The fiber composite material is first cut to obtain a first plate;

[0081] After the first plate is overlapped, it is buried in the sand and laid to form a strip;

[0082] The first overlapping part is fixed by using a first clamp with gaps.

[0083] In one specific embodiment of the present invention, the height of the first board can be 20-40cm, the length of the first board can be 1-3m, and the depth of the first board buried in the sand can be 5-15cm; the height of the first board buried in the sand above the sand can be 15-25cm, specifically 20cm; the spacing between adjacent strips can be 1-5m; and the overlap length of the first overlap can be 2-5cm. In another specific embodiment of the present invention, the material of the first clamping plate can be particleboard; the present invention does not have a special limitation on the size of the gap in the first clamping plate, and it can be designed according to the thickness of the first board; the first fixing can be achieved by inserting the overlap portion formed by the first overlap into the gap, with the first clamping plate perpendicular to the first board, and the first clamping plate can be buried in the sand to further improve the fixation of the strips.

[0084] In one specific embodiment of the present invention, when the sand barrier is a grid-type sand barrier, the preparation method of the sand barrier may include the following steps:

[0085] The fiber composite material is then cut a second time to obtain a second sheet.

[0086] After the second board is overlapped a second time, it is buried in the sand and laid to form a grid.

[0087] The second overlapping part is secured by a second clamp with gaps.

[0088] In one specific embodiment of the present invention, the height of the second board can be 10-30cm, the length of the second board can be 1-3m, and the depth of the second board buried in the sand can be less than or equal to 10cm; the height of the second board buried in the sand above the sand can be 5-20cm, specifically 5cm, 10cm, 15cm, or 20cm; the size of the grid can be 1×1m to 3×3m; the overlap length of the second overlap can be 2-5cm. In another specific embodiment of the present invention, the material of the second clamping plate can be particleboard; the second clamping plate can be buried in the sand to further improve the fixation of the grid; the second fixing can be achieved by using screws to fix the second clamping plate and the second board. Before fixing the screws, holes need to be drilled. The holes formed by drilling can be circular or square, the diameter of the circular holes can be 3-15mm, and the side length of the square holes can be 5-15mm.

[0089] In one specific embodiment of the present invention, when the sand barrier is an arc-shaped sand barrier, the method for preparing the sand barrier may include the following steps:

[0090] The fiber composite material is then cut a third time to obtain a third sheet;

[0091] The third plate is finished by a third overlap to form a rounded single unit;

[0092] The arc-shaped unit is buried in the sand to form an arc-shaped sand barrier.

[0093] In one specific embodiment of the present invention, the height of the third board can be 20-40cm, the length of the third board can be 1-3m, and the overlap length of the third overlap can be 2-5cm. In another specific embodiment of the present invention, the material of the third splice for the third overlap can be particleboard; the present invention does not have a special limitation on the size of the gap in the third splice, and it can be designed according to the thickness of the third board. In another specific embodiment of the present invention, the depth of the arc-shaped single unit buried in the sand can be 5-15cm; the height of the first board buried in the sand above the sand can be 15-25cm, specifically 20cm; the distance between the outer walls of adjacent arc-shaped single units can be 1.0-3.0m.

[0094] Figure 1 The image shows a physical copy of the first, second, or third clamping plate used in the embodiment.

[0095] This invention uses natural fibers as raw materials, modifies the interface between natural fibers and silane-based interface modifiers, and then mixes them evenly with adhesives, flexibility agents, and fertilizer slow-release agents. The mixture is then hot-pressed at high temperature to form a plate-type composite material based on natural fibers. A drilling machine is used to drill through the plate-type composite material, which is then sawn into custom-sized small panels. These panels are then laid on the desert to form strip, grid, or arc-shaped sand barriers. Finally, psammophytic plants are planted in the intervals between the strip and arc-shaped sand barriers or in the grid-shaped sand barriers, forming a composite sand barrier structure using the plate-type sand barrier structure and plants. This invention combines mechanical sand barriers with psammophytic plants for windbreak and sand fixation, overcoming the problem of secondary pollution caused by the non-degradable nature of plastic plate sand barriers and reducing costs. The grid, strip, or arc-shaped configuration method used in this invention effectively protects the sand and prevents sand erosion. The method is simple, the effect is obvious, and the fertilizer slow-release agent is slowly released during the daily degradation of the sand barrier, promoting plant growth. The composite sand-fixing barrier provided by this invention shortens the time required for plants to achieve effective sand fixation, improves the survival rate of plants, and enhances the sand-fixing effect.

[0096] Existing methods of afforestation for desertification control take a long time to form protective forests. In areas with shifting sand dunes, the sand is constantly moving, easily blowing down or burying planted shrubs and tree seedlings, resulting in low survival rates. This invention combines mechanical sand-fixing technology with afforestation for desertification control. Mechanical sand barriers stabilize shifting sand, preventing wind erosion that leads to low plant survival rates. The system also absorbs and retains rainwater, slowing down the rate of water evaporation from the sand and reducing soil erosion.

[0097] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0098] All examples used Dengkou County in the Ulan Buh Desert of Inner Mongolia as the test site for sand barrier laying.

[0099] Example 1

[0100] Using poplar wood fibers with a length of 50-300 μm and a diameter of 20-150 μm as the main raw material, γ-aminopropyltriethoxysilane (silane interface modifier) ​​was atomized and sprayed onto the surface of the poplar wood fibers, and then placed in an oven at 100℃ for dehydration reaction for 30 min to obtain modified wood fibers; wherein the mass ratio of poplar wood fibers to γ-aminopropyltriethoxysilane was 99:1;

[0101] Urea-formaldehyde resin adhesive was atomized under a pressure of 5 MPa and sprayed onto the surface of modified wood fiber. It was then uniformly mixed with polyurethane particles with an average particle size of 50 μm and sulfur-coated urea to obtain a mixture.

[0102] The mixed materials were laid into a 5cm thick fiber mat (prepared material) using a fiber laying machine. The prepared material was then placed in a high-temperature hot press and hot-pressed at 150℃ for 5 minutes to obtain a wood fiber composite material with a thickness of 2.5mm. The raw materials for preparation, by mass percentage, included 70% modified poplar fiber, 15% urea-formaldehyde resin adhesive, 10% polyurethane particles, and 5% sulfur-coated urea.

[0103] Wood fiber composite material is sawn into boards 30cm high and 1m long. Two boards are buried in the sand with an overlap of 10cm and an overlap area of ​​3cm. A piece of oriented strand board with a gap is used as a fixing device. The overlap part is inserted into the gap. The fixing device is perpendicular to the wood fiber composite board. In this way, boards are continuously laid at both ends to form a strip sand barrier with a length of 50m. Multiple sand barriers are laid again in the same way in an area 1.5m away from this strip sand barrier (the spacing between adjacent strips) to form a strip sand barrier.

[0104] The fixing device is inserted into the sand to fix the wood fiber composite board in the sand. The desert plant Haloxylon ammodendron is planted in the interval area of ​​the strip-shaped sand barrier, and the strip-shaped sand barrier structure and desert plants are used to form a composite sand-fixing barrier.

[0105] Example 2

[0106] Bamboo fiber composite materials were prepared according to the method of Example 1, except that bamboo fibers (derived from moso bamboo) with a length of 200-400 μm and a diameter of 50-200 μm were used as the main raw material; γ-glycidyl etheroxypropyltrimethoxysilane was used as a silane interface modifier; and isocyanate adhesive was used as the adhesive; the raw materials, by mass percentage, included 60% modified bamboo fiber, 10% isocyanate adhesive, 20% polyurethane particles, and 10% sulfur-coated urea.

[0107] The composite sand-fixing barrier was prepared according to the method in Example 1, except that the spacing between adjacent strips was 2m.

[0108] Example 3

[0109] Using eucalyptus fibers with a length of 200-500 μm and a diameter of 150-250 μm as the main raw material, γ-glycidoxypropyltrimethoxysilane (a silane interface modifier) ​​was atomized and sprayed onto the surface of the wood fibers. The fibers were then placed in an oven and dehydrated at 100°C for 30 min to obtain modified wood fibers. The mass ratio of eucalyptus fibers to γ-glycidoxypropyltrimethoxysilane was 98.5:1.5.

[0110] The phenolic resin adhesive was atomized under a pressure of 5 MPa and sprayed onto the surface of modified wood fiber. Then it was uniformly mixed with polyurethane particles with an average particle size of 100 μm and sulfur-coated urea to obtain a mixture.

[0111] The mixed materials were laid into a 5cm thick fiber mat (prepared material) using a fiber laying machine. The prepared material was then placed in a high-temperature hot press and hot-pressed at 150℃ for 5 minutes to obtain a wood fiber composite material with a thickness of 2.5mm. The raw materials for preparation, by mass percentage, included 70% modified wood fiber, 15% phenolic resin adhesive, 10% polyurethane particles, and 5% sulfur-coated urea.

[0112] Wood fiber composite material is sawn into boards 20cm high and 102cm long. Two boards are overlapped and buried in the sand for 10cm, with an overlap area of ​​2cm. A piece of oriented strand board with a gap is used as a fixing device. The overlapped part is inserted into the gap. The fixing device is perpendicular to the wood fiber composite board. In this way, boards are continuously laid at both ends to form a strip sand barrier with a length of 50m. The fixing devices are spaced 100cm apart. Further, multiple sand barriers are laid in the same way in an area 1m away from this strip sand barrier, thus forming multiple strip sand barriers spaced 1m apart.

[0113] A 1m long wood fiber composite board is laid perpendicular to the strip-shaped sand barrier in the interval area of ​​the strip-shaped sand barrier, and overlapped with the fixing device of the strip-shaped sand barrier. Finally, the fixing device is fixed to the vertically laid board at the overlap with screws (drilled with round holes with a diameter of 5mm), so that the natural fiber composite board is fixed in the sand in a grid pattern, with the grid size being 1m×1m.

[0114] Plant the desert plant Haloxylon ammodendron in the middle area of ​​the grid-shaped sand barrier, and use the grid-shaped sand barrier structure and desert plants to form a composite sand-fixing barrier.

[0115] Example 4

[0116] Bamboo fiber composite material was prepared according to the method of Example 2, except that the raw materials included 60% modified bamboo fiber, 15% urea-formaldehyde resin adhesive, 20% polyurethane particles, and 5% sulfur-coated urea.

[0117] The composite sand barrier was prepared according to the method in Example 3, except that the bamboo fiber composite material was sawn into boards with a height of 20cm and a length of 202cm. Two boards were buried in the sand with an overlap of 10cm and an overlap area of ​​2cm. A piece of oriented strand board with a gap was used as a fixing device. The overlap part was inserted into the gap. The fixing device was perpendicular to the bamboo fiber composite material board. Following this method, boards were continuously laid at both ends to form a strip sand barrier with a length of 50m. The fixing devices were spaced 200cm apart. Further, multiple sand barriers were laid again in the same way in an area 2m away from this strip sand barrier, thus forming multiple strip sand barriers spaced 2 meters apart.

[0118] Bamboo fiber composite material boards with a length of 2m are laid perpendicular to the strip-shaped sand barriers in the interval area of ​​the strip-shaped sand barriers, and are overlapped with the fixing device of the strip-shaped sand barriers. Finally, the fixing device is fixed to the vertically laid bamboo fiber composite material boards at the overlap part using screws (with 5mm diameter round holes). In this way, the natural fiber composite material boards are fixed in the sand in a grid pattern, with the grid size being 2m×2m.

[0119] Plant the desert plant Haloxylon ammodendron in the middle area of ​​the grid-shaped sand barrier, and use the grid-shaped sand barrier structure and desert plants to form a composite sand-fixing barrier.

[0120] Example 5

[0121] Wood fiber composite materials were prepared according to the method of Example 1, except that cedar wood fibers with a length of 300~500μm and a diameter of 150~250μm were used as the main raw materials.

[0122] Wood fiber composite material was sawn into boards 20cm high and 300cm long. The boards were then fixed by overlapping them end-to-end. A piece of oriented strand board with gaps was used as a fixing device to secure the overlapping area, leaving a 2cm overlap to form an arc-shaped sand barrier. The bottom of the arc-shaped sand barrier was buried 10cm into the sand. Following this method, arc-shaped sand barriers were formed by fixing the boards and then laid out in parallel in the desert. Multiple arc-shaped sand barriers were then laid out again in the same way, 2m away from the outer wall of the original arc-shaped sand barrier, thus forming multiple arc-shaped sand barriers. The distance between the outer walls of adjacent arc-shaped sand barriers was 2m.

[0123] Comparative Example 1

[0124] In early March 2024, a multi-functional three-dimensional sand-fixing vehicle developed by Beijing Forestry University was used to lay straw checkerboard sand barriers (made of wheat straw). The straw checkerboard sand barriers had a side length of 1m, with the loose straw inserted into the sand layer by about 15cm and protruding 25cm above the ground. The direction of the straw sand barriers was perpendicular to the prevailing wind direction of the planting area.

[0125] Comparative Example 2

[0126] Using bare sand as a comparison, no sand barriers are set up on the sand.

[0127] Figure 2 This is a photograph of a 1.5-meter-spaced strip sand barrier (before planting) prepared in Example 1. The plants in the picture are native sandy vegetation. Figure 3 A photograph of a clamp (fixing device) used to secure overlapping boards; Figure 4 A photograph of the composite sand-fixing barrier prepared in Example 1 (including plants, taken in July). Figure 5 A photograph of the checkered sand barrier (before planting) prepared in Example 3; Figure 6 A photograph of the clamp (fixing device) used to fix the grid-shaped sand barrier in Example 3; Figure 7 The image shows the actual composite sand-fixing barrier prepared in Example 3 (including plants, taken in July). Figure 8 A photograph of the actual arc-shaped sand-fixing barrier prepared in Example 5; Figure 9 This is a physical image of the straw checkerboard sand barrier shown in Comparative Example 1.

[0128] The sand fixation and sand prevention performance of Examples 1-5 and Comparative Examples 1-2 was tested using field measurements with a sand collector and a wind speed profiler, as well as wind tunnel simulation experiments. The results are listed in Table 1.

[0129] Table 1. Sand fixation performance of Examples 1-5 and Comparative Examples 1-2

[0130]

[0131] As shown in Table 1, the composite sand-fixing barrier provided by this invention can fix moisture in sand, reduce near-surface wind speed and sand transport rate, and increase the content of organic matter and total nitrogen in sand, thus achieving good sand-fixing and sand-prevention effects. This invention uses wood and bamboo fibers to manufacture sand barriers, which have natural degradable and environmentally friendly properties. During their natural growth, wood and bamboo absorb a large amount of carbon dioxide through photosynthesis, playing a role in carbon fixation. When used to make sand barriers, they can effectively fix carbon in the desert. Among them, the bamboo fiber used in Example 2 has better flexibility than the wood fiber used in Example 1, which can improve the flexibility of the composite material (board), increase the ability to swing with the wind, increase the amplitude of board shaking, and have a better windproof and sand-fixing effect. Example 4 increases the content of polyurethane particles compared to Example 1, which improves the flexibility of the fiber composite board, increases the ability to swing with the wind, increases the amplitude of board shaking, and has a better windproof and sand-fixing effect.

[0132] By using field measurements with a sand collector and a wind speed profiler, as well as wind tunnel simulation experiments, compared with Comparative Example 2, Example 3 showed that the sand-raising wind speed could be reduced by about 68%, calculated as (68-0)×100%÷68=68%; the sand transport rate could be reduced by 80.76%, calculated as (2.386-0.459)×100%÷2.386=80.76%; and the organic matter content of the sand increased by 2%, calculated as (2.34-0.35)×100%÷2.34=85.04%.

[0133] The following are the results of comparing the effectiveness of sand barriers set up in Examples 1 and 3 and Comparative Example 1 after six months:

[0134] Example 1: After more than half a year, it still has a good effect on windbreak and sand fixation, and has not collapsed; Figure 10 A photograph of the composite sand barrier after six months of use in Example 1. Figure 10 (This is a picture from January, so the plants are withered and yellow.)

[0135] Example 3: After more than half a year, it still has a good effect on windbreak and sand fixation, and has not collapsed; Figure 11 A photograph of the composite sand barrier after six months of use in Example 3. Figure 11 (This is a picture from January, so the plants are withered and yellow.)

[0136] Comparative Example 1: After more than half a year, due to excessive wind, the straw checkerboard sand barrier collapsed severely and had almost no ability to prevent wind and fix sand. Figure 12 A photograph of the straw checkerboard sand barrier set up for Comparative Example 1 after six months of use.

[0137] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A composite sand-fixing barrier, characterized in that, Including sand barriers and psammophytic plants; The sand barriers can take the form of strips, squares, or arcs; When the sand barrier is in the form of strips, the psammophytic plants are planted in the areas between adjacent strips; When the sand barrier is in the form of a grid, the psammophytic plants are planted in the middle area of ​​the grid of the sand barrier; When the sand barrier is in the form of an arc, the sand-loving plants are planted in the area between adjacent arcs; The sand barrier material is a fiber composite material, which comprises the following raw materials in weight percentage: Modified fibers 55-80%; 10-20% flexibility agent; Fertilizer slow-release agent 5-10%; Adhesive 5~15%; The modified fiber comprises natural fiber and a silane-based interface modifier grafted onto the surface of the natural fiber; the natural fiber has a length of less than or equal to 500 μm and a diameter of less than or equal to 250 μm; the silane-based interface modifier comprises one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, 1H,1H,2H,2H perfluorodecyltrichlorosilane, 1H,1H,2H,2H perfluorooctyltrichlorosilane, and 1H,1H,2H,2H perfluorodecyltriethoxysilane. The adhesive is a urea-formaldehyde resin adhesive, a phenolic resin adhesive, a melamine-modified urea-formaldehyde resin adhesive, an epoxy resin adhesive, or an isocyanate adhesive.

2. The composite sand-fixing barrier according to claim 1, characterized in that, The natural fibers include one or more of wood fiber, bamboo fiber, hemp fiber, and seaweed fiber.

3. The composite sand-fixing barrier according to claim 1, characterized in that, The flexibility agent includes polyurethane particles, polyurethane fibers, polypropylene fibers, or polyester fibers.

4. The composite sand-fixing barrier according to claim 1, characterized in that, The slow-release fertilizer includes one or more of the following: sulfur-coated urea, urea-formaldehyde, isobutylene diurea, oxamide fertilizer, nitrulase inhibitor fertilizer, and resin-coated urea.

5. The composite sand-fixing barrier according to any one of claims 1 to 4, characterized in that, The preparation method of the fiber composite material includes the following steps: Natural fibers and silane-based interface modifiers are first mixed and then dehydrated to obtain modified fibers; After the adhesive is atomized and sprayed onto the surface of the modified fiber, it is mixed with a flexibility agent and a fertilizer slow-release agent to obtain a mixture. The mixture is shaped and then hot-pressed to obtain the fiber composite material.

6. The composite sand-fixing barrier according to claim 5, characterized in that, The temperature of the dehydration reaction is 50~150℃, and the time of the dehydration reaction is 30~150min.

7. The composite sand-fixing barrier according to claim 5, characterized in that, The atomization pressure is 1~10MPa.

8. The composite sand-fixing barrier according to claim 5, characterized in that, The thickness of the formed blank is 3~50cm.

9. The composite sand-fixing barrier according to claim 5, characterized in that, The hot pressing temperature is 100~180℃, and the hot pressing holding time is 0.5~5min.

10. The composite sand-fixing barrier according to claim 1, characterized in that, The psammophytes include one or more of the following: Haloxylon ammodendron, Nitraria tangutorum, Caragana korshinskii, Caragana sinica, Calligonum mongolicum, and Artemisia argyi.

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