Dual-network interpenetrating structure dust suppression material and step-by-step polymerization dust suppression method in coal seam

Abstract

The invention relates to the technical field of coal mine dust prevention and control, in particular to a dual-network interpenetrating structure dust suppression material and a step-by-step polymerization dust suppression method in a coal seam. The dust suppression material is prepared from the following raw material components: hydroxypropyl methyl cellulose, hydroxypropyl acrylate, ammonium persulfate, acrylamide, N, N '-methylene bisacrylamide, sodium hydrogen sulfite, sodium dodecyl benzene sulfonate and deionized water, and the dust suppression material with the dual-network interpenetrating structure comprises a flexible network and a rigid network, the flexible network is a grafted product of hydroxypropyl methyl cellulose and hydroxypropyl acrylate, and the rigid network is polyacrylamide. Amido groups in the rigid network can further improve the adsorbability to dust, meanwhile, the rigid network and the flexible network form a double-network interpenetrating structure, so that the material has high water-retaining property, the double effects of chemical anchoring and physical wrapping on coal are achieved, the dust production rate in the mining process is reduced, dust production is reduced from the source, and the mining efficiency is improved. And long-acting dust suppression is achieved, and dust generated in the coal crushing process is reduced.

Description

Technical Field

[0001] This invention relates to the field of coal mine dust control technology, specifically to a dust suppression material with a double-network interpenetrating structure and a method for stepwise polymerization and dust suppression in coal seams. Background Technology

[0002] High-intensity mining in coal mines easily generates a large amount of dust. The total dust concentration in a fully mechanized mining face can reach 4000 mg / m3, and the concentration of respirable dust exceeds 1000 mg / m3. High concentrations of dust not only affect the operation and service life of mechanical equipment, but also pose a risk of dust explosion.

[0003] Currently, dust control technology in mines mainly focuses on post-mining management. Chemical dust suppressants, as an effective means of dust control, have been widely used in coal mining, transportation, and storage. However, their large molecular weight and poor permeability mean that injecting chemical dust suppressants into coal seams to achieve dust reduction at the source of mining is insufficient. Furthermore, there are currently few dust suppression materials for pre-mining source control of coal seams. Existing dust suppression materials face a contradiction between permeability and consolidation strength; low molecular weight materials have good permeability but insufficient strength, while high molecular weight materials have high strength but poor permeability, thus limiting the dust suppression effect.

[0004] Therefore, there is an urgent need for a new type of dust suppression material and dust suppression method. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a dual-network interpenetrating structure dust suppression material and a stepwise polymerization method for dust suppression in coal seams. The dual-network interpenetrating structure dust suppression material includes a flexible network and a rigid network. The flexible network is a graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, and the rigid network is polyacrylamide. The amide groups in the rigid network can further improve the adsorption of dust, while forming a dual-network interpenetrating structure with the flexible network, giving the material high water retention and creating a dual effect of "chemical anchoring-physical encapsulation" on the coal, achieving long-term dust suppression and reducing dust generation during coal crushing.

[0006] The technical solution adopted is as follows: A dust suppression material with a dual-network interpenetrating structure, comprising hydroxypropyl methylcellulose, hydroxypropyl acrylate, ammonium persulfate, acrylamide, N,N'-methylenebisacrylamide, sodium bisulfite, sodium dodecylbenzenesulfonate, and deionized water, wherein the weight percentages of each raw material are 0.5-2 parts, 1-4 parts, 0.1-0.3 parts, 6-12 parts, 0.06-0.12 parts, 0.01-0.04 parts, 0.1-0.2 parts, and 100 parts of deionized water, respectively. The dual-network interpenetrating structure dust suppression material includes a flexible network and a rigid network. The flexible network is a graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, and the rigid network is polyacrylamide.

[0007] Preferably, the preparation process of the dust suppression material is as follows: 1) First, add 0.5 to 2 parts of hydroxypropyl methylcellulose to a reaction vessel containing 90 parts of deionized water, and stir magnetically under a constant temperature water bath until the hydroxypropyl methylcellulose is completely dissolved; 2) Purge the reaction vessel with N2 to remove oxygen; 3) Add 0.01–0.03 parts of ammonium persulfate and stir to react; 4) Add 1 to 4 parts of hydroxypropyl acrylate, and then add a total of 0.04 to 0.19 parts of ammonium persulfate in 3 portions. After the reaction, the grafted product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, i.e., flexible network, is obtained. 5) After cooling the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate to room temperature, add 6-12 parts of acrylamide; 6) After the acrylamide is completely dissolved, add 0.06 to 0.12 parts of N,N'-methylenebisacrylamide and 0.09 to 0.18 parts of sodium dodecylbenzenesulfonate. After dissolution, the dust suppression material stock solution is prepared. 7) An initiation system was prepared by dissolving 0.05–0.1 parts ammonium persulfate, 0.01–0.04 parts sodium bisulfite, and 0.01–0.02 parts sodium dodecylbenzenesulfonate in 10 parts deionized water; 8) The dust suppression material stock solution is added to the initiation system to prepare a dust suppression material with a double network interpenetrating structure.

[0008] Preferably, the selected hydroxypropyl methylcellulose is type I with a viscosity of 30 mPa·s.

[0009] Preferably, the water bath temperature in preparation processes 1)-4) is 45℃~60℃; the N2 purging time in process 2) is 10~15min; the stirring reaction time in process 3) is 20~30min; and the reaction time in process 4) is 3~4h.

[0010] Preferably, the ratio of ammonium persulfate to sodium bisulfite in the initiation system is one of 1:4, 2:3, 3:2 or 4:1.

[0011] The preparation mechanism is as follows: Ammonium persulfate undergoes thermal initiation under temperature, generating sulfate radicals that abstract hydrogen atoms from the hydroxyl groups in hydroxypropyl methylcellulose, forming macromolecular free radicals of hydroxypropyl methylcellulose. Simultaneously, the double bonds of hydroxypropyl acrylate are initiated, chemically grafting with the macromolecular free radicals to generate a flexible network: a graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate. Ammonium persulfate and sodium bisulfite form a redox system, initiating the polymerization of acrylamide at room temperature to generate long polyacrylamide chains. The diene structure of N,N'-methylenebisacrylamide reacts with the double bonds on the long polyacrylamide chains, covalently linking the long chains to form a rigid polyacrylamide network. The two interpenetrating networks constitute a double-network interpenetrating structure dust suppression material.

[0012] In the dual-network structure provided by this invention, the flexible network has an amphiphilic structure. Its numerous hydrophilic groups (such as hydroxyl and methoxy groups) improve wettability, while the hydrophobic groups adsorb onto the hydrophobic surface of coal powder via van der Waals forces. Simultaneously, its side chains can adsorb multiple dust particles, promoting dust agglomeration. The amide groups in the rigid network further enhance dust adsorption, and together with the flexible network, they form a dual-network interpenetrating structure, giving the material high water retention and high permeability.

[0013] A method for stepwise polymerization of dust suppression material in coal seams, employing a dual-network interpenetrating structure dust suppression material of this invention, includes the following steps: S1: Prepare the dust suppression material stock solution; S2: The raw material of dust suppression material is injected into the coal seam through the coal seam water injection system, allowing it to seep and diffuse in the coal seam; S3: Preparation of the initiation system; S4: After the original liquid has flowed through, the initiation system will be injected into the coal seam to allow it to permeate. S5: Under the action of the initiation system, the raw material of dust suppression material cross-links and polymerizes in the coal seam to form a double network interpenetrating structure, so as to reduce the dust generation rate during the mining process.

[0014] Preferably, in step S1, the viscosity of the dust suppression material stock solution is 10-20 mPa·s, and the penetration rate is 0.08-0.15 mm / min.

[0015] Preferably, in step S2, the seepage time of the dust suppression material raw liquid in the coal seam accounts for 50-75% of the total treatment time.

[0016] Preferably, in step S3, the viscosity of the initiation system is 0.9–1 mPa·s, and the penetration rate is 0.21–0.3 mm / min.

[0017] Preferably, the cross-linking polymerization time of the dust suppression material raw liquid is at least 2 hours, and the initiation system can complete the seepage in the coal seam before initiating the cross-linking polymerization of the dust suppression material raw liquid.

[0018] The dust suppression material stock solution prepared by this invention has a significant difference in viscosity and penetration rate from the initiation system. This avoids premature polymerization reaction by the initiation system before effective diffusion is completed, while ensuring that the initiation system fully initiates the dust suppression material stock solution that has already diffused.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: To address the problem of high dust generation during coal mining and the difficulty in effectively injecting large molecular weight chemical dust suppression materials into coal seams, this invention provides a dual-network interpenetrating structure dust suppression material and a stepwise polymerization method for dust suppression within the coal seam. The dust suppression material consists of a flexible network and a rigid network, exhibiting high water retention, high permeability, and improved wettability. It achieves a dual effect of "chemical anchoring and physical encapsulation" on the coal, resulting in long-term dust suppression and reducing dust generation during coal crushing.

[0020] Based on the differences in viscosity and penetration rate between the dust suppression material concentrate and the initiation system, a stepwise polymerization strategy was adopted to achieve large-scale seepage and diffusion of the dust suppression agent concentrate within the coal seam. This prevented polymerization before effective seepage was completed. After seepage, the initiation system was ensured to fully initiate the seepage of the dust suppression material concentrate, enabling the concentrate to cross-link and polymerize within the coal seam to form a large-area double-network interpenetrating structure. This reduced the dust generation rate during mining and achieved a reduction in dust generation from the source.

[0021] The preparation method of this invention is simple, low-cost, and can be widely promoted. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the preparation process of the dust suppression material with a dual-network interpenetrating structure according to the present invention.

[0023] Figure 2 This is a schematic diagram of the diffusion of the dust suppression material raw liquid into the coal seam in Embodiment 1 of the present invention.

[0024] Figure 3 This is a schematic diagram of the cross-linking of the dust suppression material raw liquid initiated by the injection system into the coal seam in Embodiment 1 of the present invention.

[0025] Figure 4 This is a schematic diagram of the dust suppression material raw liquid polymerizing in the coal seam to form a double network interpenetrating structure in Embodiment 1 of the present invention.

[0026] In the diagram: 1. Original coal seam; 2. Dust suppression material molecules; 3. Sodium dodecylbenzenesulfonate; 4. Water molecules; 5. Initiation system; 6. Flexible network; 7. Rigid network. Detailed Implementation

[0027] The accompanying drawings are for illustrative purposes only; it should be understood that the examples mentioned below are merely for explaining the present invention, in order to facilitate the description of the present invention and simplify the description, and therefore should not be construed as limiting the present invention.

[0028] The principles and features of the present invention are described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0029] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0030] Example 1 like Figure 1 As shown, a dual-network interpenetrating structure dust suppression material comprises hydroxypropyl methylcellulose, hydroxypropyl acrylate, ammonium persulfate, acrylamide, N,N'-methylenebisacrylamide, sodium bisulfite, sodium dodecylbenzenesulfonate, and deionized water, with the following weight percentages: 1 part, 2 parts, 0.14 parts, 6 parts, 0.08 parts, 0.015 parts, 0.11 parts, and 100 parts of deionized water, respectively. The specific preparation process is as follows: 1) First, slowly add 1 part of hydroxypropyl methylcellulose to a three-necked flask containing 90 parts of deionized water, and stir magnetically under a constant temperature water bath until the hydroxypropyl methylcellulose is completely dissolved. 2) Purge the flask with N2 for 15 minutes to remove oxygen; 3) Add 0.01 parts of ammonium persulfate and stir to react for 30 minutes; 4) Add 2 parts of hydroxypropyl acrylate, and then add a total of 0.06 parts of ammonium persulfate in 3 portions. React for 4 h to prepare the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, i.e., flexible network.

[0031] 5) After cooling the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate to room temperature, add 6 parts of acrylamide; 6) After the acrylamide is completely dissolved, add 0.08 parts of N,N'-methylenebisacrylamide and 0.1 parts of sodium dodecylbenzenesulfonate. After dissolution, the dust suppression material stock solution is prepared. 7) An initiation system was prepared by dissolving 0.06 parts ammonium persulfate, 0.015 parts sodium bisulfite, and 0.01 parts sodium dodecylbenzenesulfonate in 10 parts deionized water; 8) By adding the initiation system to the dust suppression material stock solution, a dust suppression material with a double network interpenetrating structure can be prepared.

[0032] The viscosities of the prepared dust suppression material stock solution and the initiation system were 13.5 mPa·s and 0.95 mPa·s, respectively, and the penetration rates were 0.12 mm / min and 0.25 mm / min, respectively.

[0033] The dust suppression material concentrate and the initiation system are injected into the coal seam separately using a stepwise polymerization method, specifically as follows: like Figure 2 As shown, the prepared dust suppression material raw liquid is first injected into coal seam 1 through the coal seam water injection system, and the seepage time is set to 3h. The dust suppression material molecules 2 seep and diffuse rapidly in the coal seam. Sodium dodecylbenzenesulfonate 3 can improve the seepage rate and seepage range of the material in coal seam 1.

[0034] like Figure 3 , 4 As shown, after the seepage is completed, the initiation system 5 is injected into the coal seam. Due to its lower viscosity and faster seepage rate compared to the original dust suppression material liquid, the initiation system 5 can complete the seepage in the coal seam before the original dust suppression material liquid crosslinks and polymerizes. After 1.5 hours, the initiation system initiates the original dust suppression material liquid that has completed seepage and diffusion in the coal seam. The original liquid polymerizes in the coal seam to form a double-network interpenetrating structure of flexible network 6 and rigid network 7, which forms a dual effect of "chemical anchoring-physical wrapping" on the coal, achieving long-term dust suppression and reducing dust generation during coal mining and crushing.

[0035] Example 2 A dual-network interpenetrating structure dust suppression material is prepared from hydroxypropyl methylcellulose, hydroxypropyl acrylate, ammonium persulfate, acrylamide, N,N'-methylenebisacrylamide, sodium bisulfite, sodium dodecylbenzenesulfonate, and deionized water. The weight percentages of each component are 0.5 parts, 1 part, 0.16 parts, 10 parts, 0.06 parts, 0.02 parts, 0.11 parts, and 100 parts of deionized water, respectively. The specific preparation steps are as follows: 1) First, slowly add 0.5 parts of hydroxypropyl methylcellulose to a three-necked flask containing 90 parts of deionized water, and stir magnetically under a constant temperature water bath until the hydroxypropyl methylcellulose is completely dissolved. 2) Purge the flask with N2 for 15 minutes to remove oxygen; 3) Add 0.03 parts of ammonium persulfate and stir to react for 30 minutes; 4) Add 1 part of hydroxypropyl acrylate, and then add a total of 0.05 parts of ammonium persulfate in 3 portions. React for 4 h to prepare the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, i.e., flexible network.

[0036] 5) After cooling the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate to room temperature, add 10 parts of acrylamide; 6) After the acrylamide is completely dissolved, add 0.06 parts of N,N'-methylenebisacrylamide and 0.1 parts of sodium dodecylbenzenesulfonate. After dissolution, the dust suppression material stock solution is prepared. 7) An initiation system was prepared by dissolving 0.08 parts ammonium persulfate, 0.02 parts sodium bisulfite, and 0.01 parts sodium dodecylbenzenesulfonate in 10 parts deionized water; 8) By adding the initiation system to the dust suppression material stock solution, a dust suppression material with a double network interpenetrating structure can be prepared.

[0037] The viscosities of the prepared dust suppression material stock solution and the initiation system were 10.2 mPa·s and 0.98 mPa·s, respectively, and the penetration rates were 0.14 mm / min and 0.26 mm / min, respectively.

[0038] The dust suppression material concentrate and the initiation system are injected into the coal seam separately using a stepwise polymerization method, specifically as follows: First, the prepared dust suppression material raw liquid is injected into coal seam 1 through the coal seam water injection system, and the seepage time is set to 5h. The dust suppression material molecules 2 seep and diffuse rapidly in the coal seam. Sodium dodecylbenzenesulfonate 3 can improve the seepage rate and seepage range of the material in coal seam 1.

[0039] After the seepage is completed, the initiation system 5 is injected into the coal seam. Due to its lower viscosity and faster seepage rate compared to the original dust suppression material, the initiation system can complete the seepage in the coal seam before the original dust suppression material is cross-linked and polymerized. After 3 hours, the initiation system initiates the original dust suppression material that has completed seepage and diffusion in the coal seam. The original material polymerizes in the coal seam to form a double-network interpenetrating structure of flexible network 6 and rigid network 7, which forms a dual effect of "chemical anchoring-physical wrapping" on the coal, achieving long-term dust suppression and reducing dust generation during coal mining and crushing.

[0040] Example 3 A dual-network interpenetrating structure dust suppression material is prepared from hydroxypropyl methylcellulose, hydroxypropyl acrylate, ammonium persulfate, acrylamide, N,N'-methylenebisacrylamide, sodium bisulfite, sodium dodecylbenzenesulfonate, and deionized water. The weight percentages of each component are 2 parts, 3 parts, 0.24 parts, 8 parts, 0.12 parts, 0.02 parts, 0.17 parts, and 100 parts of deionized water, respectively. The specific preparation steps are as follows: 1) First, slowly add 2 parts of hydroxypropyl methylcellulose to a three-necked flask containing 90 parts of deionized water, and stir magnetically under a constant temperature water bath until the hydroxypropyl methylcellulose is completely dissolved. 2) Purge the flask with N2 for 15 minutes to remove oxygen; 3) Add 0.06 parts of ammonium persulfate and stir to react for 30 minutes; 4) Add 3 parts of hydroxypropyl acrylate, and then add a total of 0.1 parts of ammonium persulfate in 3 portions. React for 4 h to prepare the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, i.e., flexible network.

[0041] 5) After cooling the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate to room temperature, add 8 parts of acrylamide; 6) After the acrylamide is completely dissolved, add 0.12 parts of N,N'-methylenebisacrylamide and 0.15 parts of sodium dodecylbenzenesulfonate. After dissolution, the dust suppression material stock solution is prepared. 7) An initiation system was prepared by dissolving 0.08 parts ammonium persulfate, 0.02 parts sodium bisulfite, and 0.02 parts sodium dodecylbenzenesulfonate in 10 parts deionized water; 8) By adding the initiation system to the dust suppression material stock solution, a dust suppression material with a double network interpenetrating structure can be prepared.

[0042] The viscosities of the prepared dust suppression material stock solution and the initiation system were 18.9 mPa·s and 0.99 mPa·s, respectively, and the penetration rates were 0.082 mm / min and 0.21 mm / min, respectively.

[0043] The dust suppression material concentrate and the initiation system are injected into the coal seam separately using a stepwise polymerization method, specifically as follows: First, the prepared dust suppression material raw liquid is injected into coal seam 1 through the coal seam water injection system, and the seepage time is set to 8 hours. The dust suppression material molecules 2 seep and diffuse rapidly in the coal seam. Sodium dodecylbenzenesulfonate 3 can improve the seepage rate and seepage range of the material in coal seam 1.

[0044] After the seepage is completed, the initiation system 5 is injected into the coal seam. Due to its lower viscosity and faster seepage rate compared to the original dust suppression material, the initiation system can complete the seepage in the coal seam before the original dust suppression material is cross-linked and polymerized. After 4 hours, the initiation system initiates the original dust suppression material that has completed seepage and diffusion in the coal seam. The original material polymerizes in the coal seam to form a double-network interpenetrating structure of flexible network 6 and rigid network 7, which forms a dual effect of "chemical anchoring-physical wrapping" on the coal, achieving long-term dust suppression and reducing dust generation during coal mining and crushing.

[0045] Example 4 A dual-network interpenetrating structure dust suppression material is prepared from hydroxypropyl methylcellulose, hydroxypropyl acrylate, ammonium persulfate, acrylamide, N,N'-methylenebisacrylamide, sodium bisulfite, sodium dodecylbenzenesulfonate, and deionized water. The weight percentages of each component are 1 part, 4 parts, 0.2 parts, 8 parts, 0.1 parts, 0.015 parts, 0.16 parts, and 100 parts of deionized water, respectively. The specific preparation steps are as follows: 1) First, slowly add 1 part of hydroxypropyl methylcellulose to a three-necked flask containing 90 parts of deionized water, and stir magnetically under a constant temperature water bath until the hydroxypropyl methylcellulose is completely dissolved. 2) Purge the flask with N2 for 15 minutes to remove oxygen; 3) Add 0.05 parts of ammonium persulfate and stir to react for 30 minutes; 4) Add 4 parts of hydroxypropyl acrylate, and then add a total of 0.09 parts of ammonium persulfate in 3 portions. React for 4 h to prepare the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, i.e., flexible network.

[0046] 5) After cooling the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate to room temperature, add 8 parts of acrylamide; 6) After the acrylamide is completely dissolved, add 0.1 parts of N,N'-methylenebisacrylamide and 0.14 parts of sodium dodecylbenzenesulfonate. After dissolution, the dust suppression material stock solution is prepared. 7) An initiation system was prepared by dissolving 0.06 parts ammonium persulfate, 0.015 parts sodium bisulfite, and 0.02 parts sodium dodecylbenzenesulfonate in 10 parts deionized water; 8) By adding the initiation system to the dust suppression material stock solution, a dust suppression material with a double network interpenetrating structure can be prepared.

[0047] The viscosities of the prepared dust suppression material stock solution and the initiation system were 15.9 mPa·s and 0.94 mPa·s, respectively, and the penetration rates were 0.09 mm / min and 0.22 mm / min, respectively.

[0048] The dust suppression material concentrate and the initiation system are injected into the coal seam separately using a stepwise polymerization method, specifically as follows: First, the prepared dust suppression material raw liquid is injected into coal seam 1 through the coal seam water injection system, and the seepage time is set to 6 hours. The dust suppression material molecules 2 seep and diffuse rapidly in the coal seam. Sodium dodecylbenzenesulfonate 3 can improve the seepage rate and seepage range of the material in coal seam 1.

[0049] After the seepage is completed, the initiation system is injected into the coal seam. Due to its lower viscosity and faster seepage rate compared to the original dust suppression material, the initiation system can complete the seepage in the coal seam before the original dust suppression material crosslinks and polymerizes. After 3 hours, the initiation system initiates the original dust suppression material that has completed seepage and diffusion in the coal seam. The original material polymerizes in the coal seam to form a double-network interpenetrating structure with flexible and rigid networks interpenetrating each other. This forms a dual effect of "chemical anchoring and physical wrapping" on the coal, achieving long-term dust suppression and reducing dust generation during coal mining and crushing.

[0050] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A dust suppression material with a dual-network interpenetrating structure, characterized in that, The raw materials include hydroxypropyl methylcellulose, hydroxypropyl acrylate, ammonium persulfate, acrylamide, N,N'-methylenebisacrylamide, sodium bisulfite, sodium dodecylbenzenesulfonate, and deionized water, with the following weight percentages: 0.5–2 parts, 1–4 parts, 0.1–0.3 parts, 6–12 parts, 0.06–0.12 parts, 0.01–0.04 parts, 0.1–0.2 parts, and 100 parts of deionized water. The dual-network interpenetrating structure dust suppression material includes a flexible network and a rigid network. The flexible network is a graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, and the rigid network is polyacrylamide.

2. The dust suppression material with a double-network interpenetrating structure according to claim 1, characterized in that, The preparation process of the dust suppression material is as follows: 1) First, add 0.5 to 2 parts of hydroxypropyl methylcellulose to a reaction vessel containing 90 parts of deionized water, and stir magnetically under a constant temperature water bath until the hydroxypropyl methylcellulose is completely dissolved; 2) Purge the reaction vessel with N2 to remove oxygen; 3) Add 0.01–0.03 parts of ammonium persulfate and stir to react; 4) Add 1 to 4 parts of hydroxypropyl acrylate, and then add a total of 0.04 to 0.19 parts of ammonium persulfate in 3 portions. After the reaction, the grafted product of hydroxypropyl methylcellulose and hydroxypropyl acrylate, i.e., flexible network, is obtained. 5) After cooling the graft product of hydroxypropyl methylcellulose and hydroxypropyl acrylate to room temperature, add 6-12 parts of acrylamide; 6) After the acrylamide is completely dissolved, add 0.06 to 0.12 parts of N,N'-methylenebisacrylamide and 0.09 to 0.18 parts of sodium dodecylbenzenesulfonate. After dissolution, the dust suppression material stock solution is prepared. 7) An initiation system was prepared by dissolving 0.05–0.1 parts ammonium persulfate, 0.01–0.04 parts sodium bisulfite, and 0.01–0.02 parts sodium dodecylbenzenesulfonate in 10 parts deionized water; 8) The dust suppression material stock solution is added to the initiation system to prepare a dust suppression material with a double network interpenetrating structure.

3. The dust suppression material with a dual-network interpenetrating structure according to claim 2, characterized in that, The selected hydroxypropyl methylcellulose is type I with a viscosity of 30 mPa·s.

4. The dust suppression material with a dual-network interpenetrating structure according to claim 2, characterized in that, In preparation processes 1)-4), the water bath temperature is 45℃~60℃; in process 2), the N2 purging time is 10~15min; in process 3), the stirring reaction time is 20~30min; and in process 4), the reaction time is 3~4h.

5. The dust suppression material with a double-network interpenetrating structure according to claim 2, characterized in that, The ratio of ammonium persulfate to sodium bisulfite in the initiation system is one of 1:4, 2:3, 3:2 or 4:

1.

6. A method for stepwise polymerization of dust suppression material in a coal seam, employing a double-network interpenetrating structure dust suppression material as described in any one of claims 1-5, characterized in that... Includes the following steps: S1: Prepare the dust suppression material stock solution; S2: The raw material of dust suppression material is injected into the coal seam through the coal seam water injection system, allowing it to seep and diffuse in the coal seam; S3: Preparation of the initiation system; S4: After the original liquid has flowed through, the initiation system will be injected into the coal seam to allow it to permeate. S5: Under the action of the initiation system, the raw material of dust suppression material cross-links and polymerizes in the coal seam to form a double network interpenetrating structure, so as to reduce the dust generation rate during the mining process.

7. A method for stepwise polymerization of dust suppression material in a coal seam according to claim 6, characterized in that, In step S1, the viscosity of the dust suppression material stock solution is 10-20 mPa·s, and the penetration rate is 0.08-0.15 mm / min.

8. A method for stepwise polymerization of dust suppression material in a coal seam according to claim 6, characterized in that, In step S2, the seepage time of the dust suppression material raw liquid in the coal seam accounts for 50-75% of the total treatment time.

9. A method for stepwise polymerization of dust suppression material in a coal seam according to claim 6, characterized in that, In step S3, the viscosity of the initiation system is 0.9–1 mPa·s, and the penetration rate is 0.21–0.3 mm / min.

10. A method for stepwise polymerization of dust suppression material in a coal seam according to claim 6, characterized in that, The cross-linking polymerization time of the dust suppression material raw liquid is at least 2 hours, and the initiation system can complete the seepage in the coal seam before initiating the cross-linking polymerization of the dust suppression material raw liquid.

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