Agricultural and forestry waste-based recoverable foam material as well as preparation method and application thereof

Abstract

The invention discloses an agricultural and forestry waste-based recoverable foam material as well as a preparation method and application thereof, and belongs to the technical field of environment-friendly materials. The composite material comprises the following components in parts by weight: 1-50 parts of biomass waste wood and bamboo fiber powder, 10-40 parts of natural inorganic powder, 10-30 parts of thermoplastic resin, 1-3 parts of an environment-friendly foaming agent and 2-5 parts of a compatilizer. The foam material prepared by the invention presents a unique three-dimensional porous network structure, has mechanical properties of light weight and high strength, ecological properties of green and environmental protection and recyclable characteristics, shows excellent environmental adaptability and engineering practicability in sand barrier engineering application, and has a wide application prospect. The problems that a traditional sand barrier material is difficult to degrade and causes secondary pollution after being discarded are thoroughly solved, meanwhile, an environment-friendly foaming technology and a green auxiliary system are adopted, the technological process is short, energy consumption is low, no three wastes are discharged, and the requirements of circular economy and clean production are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmentally friendly materials, and in particular relates to a recyclable foam material based on agricultural and forestry wastes, and a preparation method and application thereof. Background Art

[0002] Wind erosion and desertification are a major form of land degradation in arid and semi-arid regions, posing a serious threat to regional ecological and environmental security and sustainable agricultural development. Vast expanses of wind-eroded sandy lands are found in Northwest and North my country, as well as in parts of the plateau. These areas experience strong winds year-round, low vegetation cover, and fragile soil structure, making them prone to frequent sandstorms. To curb the harm posed by wind and sand, national and local governments are vigorously promoting sand prevention and control projects, extensively utilizing various technologies such as artificial sand barriers, vegetation restoration, and water conservancy projects to stabilize sand dunes, promote vegetation growth, and improve the ecological environment.

[0003] Artificial sand barriers, due to their simple construction, rapid effectiveness, and strong environmental adaptability, have become a common measure in sand fixation projects. Traditional sand barriers are typically made of wheat straw, rice straw, bamboo strips, nylon rope, plastic mesh, or metal materials. These are woven into grids, strips, or honeycomb structures and laid on the sandy surface. They reduce wind speed, intercept quick sand, and increase surface humidity, creating favorable conditions for plant growth.

[0004] However, these traditional materials have many disadvantages: wheat straw, rice straw and other plant resources are difficult to collect and are prone to rot and become ineffective; synthetic materials such as plastic and nylon are difficult to degrade and form white pollution after aging; metal sand barriers are expensive and prone to aging and cracking in extreme climates or high-salt and alkaline environments, which seriously restricts their long-term application in ecologically weak areas.

[0005] With the advancement of the "Carbon Peak and Carbon Neutrality" strategy and the deepening of the concept of sustainable development, new environmentally friendly, biodegradable and recyclable sand barrier materials have become a research hotspot. Bio-based materials, made from renewable biomass such as plant oils, natural resins, cellulose, and lignin, are considered an ideal alternative to traditional sand barrier materials due to their environmental friendliness and designability. Some biomass polymers, after chemical modification, can possess excellent mechanical properties, weather resistance, and water stability, maintaining structural stability in the harsh desert environment.

[0006] Although attempts have been made to use biomass raw materials in the preparation of sand barrier materials, key technical bottlenecks remain. For example, insufficient control of the hydrophilic and hydrophobic properties of the material interface leads to weak adhesion to sand particles; the degradation cycle is difficult to precisely control, making it impossible to match the vegetation restoration process; and the high production costs make it difficult to achieve industrialization and promotion. Therefore, the development of new bio-based sand barrier materials based on renewable resources, with good environmental adaptability and stable structural properties, is of great significance to promoting the construction of a green ecological protection system and improving the level of desert control technology. Summary of the Invention

[0007] The first technical problem to be solved by the present invention is to provide a recyclable foam material based on agricultural and forestry waste, which is lightweight, high-strength, durable, and can resist wind and sand erosion for a long time; the second technical problem to be solved by the present invention is a preparation method of a recyclable foam material based on agricultural and forestry waste, which solves the problem of uneven foaming of the biomass-inorganic hybrid system through twin-screw segmented temperature control and precise control of die head pressure; the third technical problem to be solved by the present invention is the application of the recyclable foam material in sand barriers.

[0008] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0009] The invention discloses a recyclable foam material based on agricultural and forestry wastes, which is composed of the following components by weight: biomass waste wood, 1-50 parts of bamboo fiber powder, 10-40 parts of natural inorganic powder, 10-30 parts of thermoplastic resin, 1-3 parts of environmentally friendly foaming agent and 2-5 parts of compatibilizer.

[0010] Furthermore, the fiber powder has a length of ≤200 μm.

[0011] Furthermore, the natural inorganic powder is selected from one or more of calcium carbonate and quartz sand, the mass ratio of calcium carbonate to quartz sand is 1:1 to 3:1, the mesh number of calcium carbonate is 300 to 1000 mesh, and the mesh number of quartz sand is 300 to 1000 mesh.

[0012] Furthermore, the thermoplastic resin is selected from one or more of polylactic acid, polyethylene, polypropylene, and polystyrene.

[0013] Furthermore, the environmentally friendly foaming agent is selected from one or more of low-boiling point aliphatic hydrocarbons, halogenated hydrocarbons, and sodium bicarbonate.

[0014] Furthermore, the compatibilizer is selected from one or more of maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene.

[0015] Furthermore, the method for preparing the agricultural and forestry waste-based recyclable foam material comprises the following steps:

[0016] 1) drying the biomass waste wood and bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0017] 2) adding the biomass waste wood, bamboo fiber powder, thermoplastic resin, environmentally friendly foaming agent, and compatibilizer obtained after drying in step 1) into a high-speed mixer and mixing and stirring at 60-100° C. for 10-30 minutes;

[0018] 3) The mixture obtained in step 2) is melt-blended and foamed through a twin-screw extruder, wherein the temperature of the twin-screw extruder is set to: 100-160° C. in zone 1, 130-250° C. in zone 2, and 150-280° C. in zone 3; the screw speed is 200-300 rpm; and the die pressure is 8-12 MPa;

[0019] 4) The material extruded in step 3) is cooled and shaped, and then granulated by a pelletizer or directly foamed to obtain a recyclable foam material.

[0020] Furthermore, the agricultural and forestry waste-based recyclable foam material is used in sand barriers.

[0021] Furthermore, sand barriers for windbreak and sand control include the following structural forms: upright sand barriers with a height of 0.5 to 2m and a depth of 0.2 to 0.5m buried in the sand layer; flat sand barriers with laying methods including matrix, grid or herringbone; and breathable sand barriers with a permeability coefficient of 0.3 to 0.7.

[0022] Furthermore, after the sand barrier completes its sand prevention task, the recycling steps include: physical recycling: after cleaning and crushing, it is added into new materials at a ratio of 30-50wt% for further processing; chemical recycling: depolymerization at 250-850°C and in a nitrogen atmosphere to recover monomers or oligomers.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The foam material prepared by the present invention presents a unique three-dimensional porous network structure, which has the advantages of light weight and high strength mechanical properties, durability, green and environmentally friendly ecological properties and recyclable properties, and can resist wind and sand erosion for a long time.

[0025] (2) The present invention solves the problem of uneven foaming of the biomass-inorganic hybrid system by controlling the temperature of the twin-screw segment and precisely controlling the die head pressure.

[0026] (3) The present invention adopts environmentally friendly foaming technology and green additive system, with a short process flow, low energy consumption and no three wastes discharged, which meets the requirements of circular economy and clean production.

[0027] (4) The raw materials used in this invention are bio-based, accounting for a high proportion, achieving sustainable resource utilization; and the use of local resources such as quartz sand and wood cellulose reduces transportation costs. The wood and bamboo fibers are synergistically reinforced with inorganic powders, combined with the bonding effect of thermoplastic resins, to achieve a lightweight and high-strength material.

[0028] (5) The foam material prepared by the present invention effectively reduces wind speed, intercepts quicksand, and assists in sand control and desertification prevention and control in sand barrier projects. It exhibits excellent environmental adaptability and engineering practicality, and completely solves the problem of traditional sand barrier materials being difficult to degrade and causing secondary pollution after disposal. Compared with traditional materials, the present invention reduces the cost of sand barrier preparation by 30% to 50% and extends its service life by 2 to 3 times. It has significant technical advantages and economic benefits in the fields of ecological restoration and desertification control, and provides an innovative material solution for desertification prevention and control projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the infrared spectrum of the recyclable foam material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0030] The present invention will be further illustrated below with reference to specific examples. The examples are implemented based on the technical solutions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0031] In the following examples, PLA is polylactic acid, PE is polyethylene, PP is polypropylene, PS is polystyrene, maleic anhydride grafted polyethylene is PE-g-MAH, and maleic anhydride grafted polypropylene is PP-g-MAH, all of which are commercially available industrial-grade raw materials.

[0032] In the following examples, the fiber length is ≤200 μm (mechanically crushed, homemade); the mesh size of calcium carbonate is 300-1000 mesh, and the mesh size of quartz sand is 300-1000 mesh, both of which are obtained from the Ulan Buh Desert in Inner Mongolia.

[0033] In the following examples, the recyclable foam material is processed into a sheet or grid structure by a twin-screw extrusion foaming process. The thickness of the sheet structure is 5 to 50 mm, and the mesh size of the grid structure is 10 to 50 mm.

[0034] In the following examples, the aspect ratio of the twin-screw extruder is 40:1 to 52:1.

[0035] Example 1

[0036] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0037] (1) drying 40 parts of biomass waste wood and bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0038] (2) Mix the wood fiber powder dried in step (1) with 15 parts of calcium carbonate, 15 parts of quartz sand, 25 parts of PS, 2 parts of sodium bicarbonate, and 3 parts of PE-g-MAH, put them into a high-speed mixer, and mix them at 60-100° C. for 10-30 minutes;

[0039] (3) Twin-screw extrusion temperature was 155°C in zone 1, 200°C in zone 2, and 260°C in zone 3, screw speed was 250 rpm, and die pressure was 10 MPa to achieve uniform foaming;

[0040] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.25 g / cm 3 , the compressive strength is 1.8MPa.

[0041] Figure 1 The infrared spectrum of the recyclable foam material prepared for this application shows that 3298 cm -1 The broad peak at 2918 cm is the characteristic absorption peak of -OH. -1 The peak at 1599 cm is the CH stretching vibration absorption peak of -CH3 and -CH2- in wood and bamboo powder and PS resin. -1 、1492cm -1 、1450cm -1 The characteristic absorption peak of phenylpropane skeleton of lignin in wood and bamboo powder is 1022cm -1 The peaks are characteristic absorption peaks of cellulose-COC-ether bonds contained in wood and bamboo powder. Relevant characterizations show that the main component of the recyclable foam material is wood and bamboo fiber powder.

[0042] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has circular holes with a diameter of 30mm and a ventilation rate of 30%. The entire board is paved in the sand in a grid pattern, which can effectively reduce the ground wind speed, block the movement of sand and dust, and play a role in preventing wind and sand.

[0043] Example 2

[0044] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0045] (1) drying 50 parts of biomass waste wood fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0046] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 20 parts of calcium carbonate, 10 parts of quartz sand, 20 parts of PP, 3 parts of sodium bicarbonate, and 5 parts of PP-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0047] (3) Twin-screw extrusion temperature was 160°C in zone 1, 180°C in zone 2, and 190°C in zone 3, screw speed was 300 rpm, and die pressure was 12 MPa to achieve uniform foaming;

[0048] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.18 g / cm 3 , the compressive strength is 2.1MPa.

[0049] The prepared foam material is processed into boards of a certain size, with a thickness of 5mm, a length of 1200mm, and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has circular holes with a diameter of 35mm and a permeability of 36%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0050] Example 3

[0051] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0052] (1) drying 10 parts of biomass waste wood fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0053] (2) Mix the dried wood and bamboo fiber powder from step (1) with 10 parts of calcium carbonate, 10 parts of quartz sand, 30 parts of PE, 1 part of sodium bicarbonate, and 2 parts of PE-g-MAH, put the mixture into a high-pressure mixer, and mix at 60-100° C. for 10-30 minutes;

[0054] (3) Twin-screw extrusion temperature was 100°C in zone 1, 150°C in zone 2, and 180°C in zone 3, screw speed was 200 rpm, and die pressure was 8 MPa to achieve uniform foaming;

[0055] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.35 g / cm 3 , the compressive strength is 2.5MPa.

[0056] The prepared foam material is processed into boards of a certain size, with a thickness of 10mm, a length of 1200mm and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has circular holes with a diameter of 50mm and a ventilation rate of 68%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0057] Example 4

[0058] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0059] (1) drying 30 parts of biomass waste bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0060] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 25 parts of calcium carbonate, 15 parts of quartz sand, 25 parts of PS, 2 parts of sodium bicarbonate, and 4 parts of PP-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0061] (3) Twin-screw extrusion temperature was 158°C in zone 1, 220°C in zone 2, and 270°C in zone 3, screw speed was 280 rpm, and die pressure was 11 MPa to achieve uniform foaming;

[0062] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.22 g / cm 3 , compressive strength is 2.0MPa, and the open porosity is 85%.

[0063] The prepared foam material is processed into boards of a certain size, with a thickness of 15mm, a length of 1200mm, and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has circular holes with a diameter of 40mm and a permeability of 41%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and has a wind-proof and sand-control effect.

[0064] Example 5

[0065] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0066] (1) drying 20 parts of biomass waste bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0067] (2) Mix the dried wood and bamboo fiber powder obtained in step (1) with 12 parts of calcium carbonate, 18 parts of quartz sand, 1 part of sodium bicarbonate, 28 parts of a blend of PLA and PP (mass ratio 1:1), and 3 parts of PE-g-MAH, put the mixture into a high-pressure mixer, and mix at 60-100° C. for 10-30 minutes;

[0068] (3) Twin-screw extrusion temperature was 156°C in zone 1, 176°C in zone 2, and 200°C in zone 3, screw speed was 260 rpm, and die pressure was 9 MPa to achieve uniform foaming;

[0069] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.20 g / cm 3 , the compressive strength is 1.9MPa.

[0070] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 250mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has regular triangular holes with a side length of 30mm and a ventilation rate of 30%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0071] Example 6

[0072] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0073] (1) drying 45 parts of biomass waste wood fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0074] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 30 parts of calcium carbonate, 10 parts of quartz sand, 20 parts of PE, 1.5 parts of sodium bicarbonate, and 2.5 parts of PP-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0075] (3) Twin-screw extrusion temperature was 110°C in zone 1, 162°C in zone 2, and 182°C in zone 3, the screw speed was 220 rpm, and the die pressure was 8.5 MPa to achieve uniform foaming;

[0076] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.28 g / cm 3 , the compressive strength is 2.2MPa.

[0077] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 300mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has circular holes with a diameter of 40mm and a permeability of 42%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and has a wind-proof and sand-control effect.

[0078] Example 7

[0079] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0080] (1) drying 15 parts of biomass waste bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0081] (2) Mixing the dried wood and bamboo fiber powder obtained in step (1) with 8 parts of calcium carbonate, 12 parts of quartz sand, 27 parts of PS, 2 parts of sodium bicarbonate, and 3 parts of PE-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0082] (3) Twin-screw extrusion temperature was 154°C in zone 1, 174°C in zone 2, and 184°C in zone 3, the screw speed was 240 rpm, and the die pressure was 10 MPa to achieve uniform foaming;

[0083] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.32 g / cm 3 , the compressive strength is 2.3MPa.

[0084] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1000mm and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has regular hexagonal holes with a side length of 20mm and a ventilation rate of 35%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0085] Example 8

[0086] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0087] (1) drying 25 parts of biomass waste wood fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0088] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 15 parts of calcium carbonate, 15 parts of quartz sand, 20 parts of PLA, 3 parts of sodium bicarbonate, and 5 parts of PP-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0089] (3) Twin-screw extrusion temperature was 160°C in zone 1, 200°C in zone 2, and 230°C in zone 3, screw speed was 300 rpm, and die pressure was 12 MPa to achieve uniform foaming;

[0090] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.16 g / cm 3 , compressive strength is 1.7MPa, and porosity is 90%.

[0091] The prepared foam material is processed into boards of a certain size, with a thickness of 10mm, a length of 1200mm, and a width of 250mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has regular hexagonal holes with a side length of 30mm and a ventilation rate of 45%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and has a wind-proof and sand-control effect.

[0092] Example 9

[0093] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0094] (1) drying 25 parts of biomass waste wood and bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0095] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 20 parts of calcium carbonate, 20 parts of quartz sand, 25 parts of PP, 1 part of sodium bicarbonate, and 3 parts of PE-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0096] (3) Twin-screw extrusion temperature was 155°C in zone 1, 180°C in zone 2, and 210°C in zone 3, screw speed was 250 rpm, and die pressure was 10 MPa to achieve uniform foaming;

[0097] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.23 g / cm 3 , the compressive strength is 1.9MPa.

[0098] The prepared foam material is processed into boards of a certain size, with a thickness of 15mm, a length of 1000mm and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has circular holes with a diameter of 50mm and a ventilation rate of 47%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0099] Example 10

[0100] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0101] (1) Drying 20 parts of biomass waste wood fiber powder and 15 parts of bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0102] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 18 parts of calcium carbonate, 12 parts of quartz sand, 25 parts of PS, 2.5 parts of sodium bicarbonate, and 4 parts of PP-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0103] (3) Twin-screw extrusion temperature was 157°C in zone 1, 240°C in zone 2, and 280°C in zone 3, with a screw speed of 270 rpm and a die pressure of 11 MPa to achieve uniform foaming;

[0104] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.21 g / cm 3 , the compressive strength is 2.0MPa.

[0105] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has square holes with a side length of 30mm and a permeability of 33%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and has a wind-proof and sand-control effect.

[0106] Example 11

[0107] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0108] (1) drying 12 parts of biomass waste bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0109] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 10 parts of calcium carbonate, 10 parts of quartz sand, 2 parts of low-boiling-point halogenated hydrocarbons, 28 parts of a PLA and PE blend (mass ratio 2:1), and 3 parts of PE-g-MAH, and placing the mixture in a high-pressure mixer and mixing at 60-100° C. for 10-30 minutes;

[0110] (3) Twin-screw extrusion temperature was 153°C in zone 1, 173°C in zone 2, and 210°C in zone 3, screw speed was 230 rpm, and die pressure was 9 MPa to achieve uniform foaming;

[0111] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.30 g / cm 3 , the compressive strength is 2.4MPa.

[0112] The prepared foam material is processed into boards of a certain size, with a thickness of 30mm, a length of 1200mm and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has prismatic holes with a side length of 30mm and a ventilation rate of 40%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0113] Example 12

[0114] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0115] (1) drying 15 parts of biomass waste wood fiber powder and 15 parts of biomass waste bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0116] (2) mixing the dried wood and bamboo fiber powder obtained in step (1) with 22 parts of calcium carbonate, 8 parts of quartz sand, 20 parts of PP, 2 parts of sodium bicarbonate, and 4 parts of PP-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0117] (3) Twin-screw extrusion temperature was 159°C in zone 1, 179°C in zone 2, and 210°C in zone 3, with a screw speed of 290 rpm and a die pressure of 11.5 MPa to achieve uniform foaming;

[0118] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.17 g / cm 3 , the compressive strength is 1.8MPa.

[0119] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 300mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has holes with a diameter of 50mm and a permeability of 48%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0120] Example 13

[0121] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0122] (1) drying 22 parts of biomass waste bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0123] (2) Mix the dried wood and bamboo fiber powder from step (1) with 14 parts of calcium carbonate, 16 parts of quartz sand, 28 parts of PS, 1.2 parts of sodium bicarbonate, and 3 parts of PE-g-MAH, put the mixture into a high-pressure mixer, and mix at 60-100° C. for 10-30 minutes;

[0124] (3) Twin-screw extrusion temperature was 151°C in zone 1, 245°C in zone 2, and 275°C in zone 3, with a screw speed of 210 rpm and a die pressure of 8.5 MPa to achieve uniform foaming;

[0125] (4) The extrudate obtained in step (3) is cooled and shaped, and then granulated by a pelletizer to obtain organic-inorganic hybrid recyclable foam material particles, the density of which is 0.33 g / cm 3 , the compressive strength is 2.3MPa.

[0126] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 200mm. Half of the width is inserted into the sand and the other half is exposed above the sand and dust. The upper part has regular pentagonal holes with a side length of 30mm and a ventilation rate of 40%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0127] Example 14

[0128] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0129] (1) drying 19 parts of biomass waste wood fiber powder and 19 parts of biomass waste bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %;

[0130] (2) mixing the wood and bamboo fiber powder dried in step (1) with 24 parts of calcium carbonate, 16 parts of quartz sand, 22 parts of PLA, 2.2 parts of low-boiling-point halogenated hydrocarbons, and 3 parts of PP-g-MAH, placing the mixture in a high-pressure mixer, and mixing at 60-100° C. for 10-30 minutes;

[0131] (3) Twin-screw extrusion temperature was 156°C in zone 1, 176°C in zone 2, and 186°C in zone 3, the screw speed was 260 rpm, and the die pressure was 10 MPa to achieve uniform foaming;

[0132] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.24 g / cm 3 , the compressive strength is 1.9MPa.

[0133] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 200mm. The bottom edge is serrated, with half of the width inserted into the sand and half exposed above the sand and dust. The upper part has 30mm long holes and a ventilation rate of 30%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and plays a role in preventing wind and sand.

[0134] Example 15

[0135] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0136] (1) 18 parts of biomass waste bamboo fiber powder were dried at 105-110° C. to a moisture content of ≤2 wt %;

[0137] (2) Mix the dried wood and bamboo fiber powder from step (1) with 16 parts of calcium carbonate, 14 parts of quartz sand, 1.5 parts of sodium bicarbonate, 28 parts of PE, and 3 parts of PE-g-MAH, put the mixture into a high-pressure mixer, and mix at 60-100° C. for 10-30 minutes;

[0138] (3) Twin-screw extrusion temperature was 154°C in zone 1, 174°C in zone 2, and 184°C in zone 3, the screw speed was 240 rpm, and the die pressure was 9.5 MPa to achieve uniform foaming;

[0139] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.26 g / cm 3 , the compressive strength is 2.1MPa.

[0140] The prepared foam material is processed into boards of a certain size, with a thickness of 20mm, a length of 1200mm and a width of 200mm. The bottom edge is comb-shaped, with half of the width inserted into the sand and half exposed above the sand and dust. The upper part has holes with a diameter of 30mm and a permeability of 30%. The entire board is paved in the sand in a grid pattern, which effectively reduces the ground wind speed, blocks the movement of sand and dust, and has a wind-proof and sand-control effect.

[0141] Comparative Example 1

[0142] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0143] (1) 18 parts of biomass waste bamboo fiber powder were dried at 105-110° C. to a moisture content of ≤2 wt %;

[0144] (2) Mixing the dried wood and bamboo fiber powder obtained in step (1) with 16 parts of calcium carbonate, 14 parts of quartz sand, 2 parts of sodium bicarbonate, and 28 parts of PE, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0145] (3) The twin-screw extrusion temperature was 154°C in zone 1, 174°C in zone 2, and 184°C in zone 3. The screw speed was 240 rpm and the die pressure was 9.5 MPa. However, the foaming was not uniform.

[0146] (4) The extrudate of step (3) is subjected to a twin-screw extrusion foaming process and cooled and shaped to obtain an organic-inorganic hybrid recyclable foam material having a density of 0.31 g / cm 3 , the compressive strength is 1.8MPa, the pore uniformity is poor, the material surface is rough, and the pore sizes are different.

[0147] Comparative Example 2

[0148] A method for preparing a recyclable foam material based on agricultural and forestry wastes comprises the following steps:

[0149] (1) 18 parts of biomass waste bamboo fiber powder were dried at 105-110° C. to a moisture content of ≤2 wt %;

[0150] (2) Mixing the dried wood and bamboo fiber powder obtained in step (1) with 16 parts of calcium carbonate, 14 parts of quartz sand, 2 parts of sodium bicarbonate, and 3 parts of PE-g-MAH, placing the mixture in a high-pressure mixer, and mixing the mixture at 60-100° C. for 10-30 minutes;

[0151] (3) The twin-screw extrusion temperature was 154°C in zone 1, 174°C in zone 2, and 184°C in zone 3. The screw speed was 240 rpm and the die pressure was 9.5 MPa. No foaming was possible.

[0152] (4) After the extrudate in step (3) is cooled and shaped through a twin-screw extrusion foaming process, no organic-inorganic hybrid recyclable foam material can be obtained, and the material becomes an irregular slag shape.

[0153] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A recyclable foam material based on agricultural and forestry waste, characterized in that: The composition by weight is as follows: 1-50 parts of biomass waste wood and bamboo fiber powder, 10-40 parts of natural inorganic powder, 10-30 parts of thermoplastic resin, 1-3 parts of environmentally friendly foaming agent, and 2-5 parts of compatibilizer.

2. The agricultural and forestry waste-based recyclable foam material according to claim 1, characterized in that: The fiber powder has a length of ≤200 μm.

3. The agricultural and forestry waste-based recyclable foam material according to claim 1, characterized in that: The natural inorganic powder is selected from one or more of calcium carbonate and quartz sand, the mass ratio of calcium carbonate to quartz sand is 1:1 to 3:1, the mesh number of calcium carbonate is 300 to 1000 meshes, and the mesh number of quartz sand is 300 to 1000 meshes.

4. The agricultural and forestry waste-based recyclable foam material according to claim 1, characterized in that: The thermoplastic resin is selected from one or more of polylactic acid, polyethylene, polypropylene and polystyrene.

5. The agricultural and forestry waste-based recyclable foam material according to claim 1, characterized in that: The environmentally friendly foaming agent is selected from one or more of low-boiling point aliphatic hydrocarbons, halogenated hydrocarbons, and sodium bicarbonate.

6. The agricultural and forestry waste-based recyclable foam material according to claim 1, characterized in that: The compatibilizer is selected from one or more of maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene.

7. The method for preparing a recyclable foam material based on agricultural and forestry waste according to any one of claims 1 to 6, characterized in that: The following steps are involved: 1) drying the biomass waste wood and bamboo fiber powder at 105-110° C. to a moisture content of ≤2 wt %; 2) adding the biomass waste wood, bamboo fiber powder, natural inorganic powder, thermoplastic resin, environmentally friendly foaming agent, and compatibilizer obtained from step 1) into a high-speed mixer and mixing and stirring at 60-100° C. for 10-30 minutes; 3) The mixture obtained in step 2) is melt-blended and foamed through a twin-screw extruder, wherein the temperature of the twin-screw extruder is set to: 100-160° C. in zone 1, 130-250° C. in zone 2, and 150-280° C. in zone 3; the screw speed is 200-300 rpm; and the die pressure is 8-12 MPa; 4) The material extruded in step 3) is cooled and shaped, and then granulated by a pelletizer or directly foamed to obtain foamable particles or recyclable foam material.

8. Use of the agricultural and forestry waste-based recyclable foam material according to claim 1 in sand barriers.

9. The use of the agricultural and forestry waste-based recyclable foam material in sand barriers according to claim 8, characterized in that: Sand barriers for wind and sand control include the following structural forms: upright sand barriers with a height of 0.5 to 2m and a depth of 0.2 to 0.5m buried in the sand layer; flat sand barriers with laying methods including matrix, grid or herringbone; and breathable sand barriers with a permeability coefficient of 0.3 to 0.

7.

10. The use of the agricultural and forestry waste-based recyclable foam material in sand barriers according to claim 8, characterized in that: After the sand barrier completes its sand prevention task, the recycling steps include: physical recycling: after cleaning and crushing, it is added into new materials at a ratio of 30-50wt% for further processing; chemical recycling: depolymerization at 250-850℃ and nitrogen atmosphere to recover monomers or oligomers.

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