Preparation process of high polymer coal spontaneous combustion inhibitor

Abstract

The application relates to the technical field of inhibitors, and discloses a preparation process of a high-polymer coal spontaneous combustion inhibitor. The process comprises the following steps: S1, uniformly dispersing polydopamine microcapsules in deionized water, adding GMA grafted CNC, and stirring until uniform to obtain a mixed solution; S2, adding acrylic acid and acrylamide into the mixed solution prepared in step S1 in sequence, then adding a crosslinking agent and an initiator, stirring under nitrogen protection, forming a gel after reaction, immersing the gel in ethanol to replace moisture, and freeze-drying to obtain the inhibitor. The preparation process improves the thermal stability and inhibition effect of the inhibitor.

Description

Technical Field

[0001] This invention relates to the field of inhibitor technology, and in particular to a preparation process of a polymer coal self-ignition inhibitor. Background Technology

[0002] Spontaneous combustion of coal is a common safety hazard during coal mining, storage, and transportation. It not only wastes coal resources but also poses a serious threat to the environment and human health. Statistics show that approximately 80% of the coal seams mined in my country have a high tendency for spontaneous combustion, and mines mining thick coal seams almost universally experience this problem. The toxic and harmful gases produced by spontaneous combustion, such as CO and SO2, pose a serious threat to human physical and mental health and may even trigger major accidents such as gas and coal dust explosions. Furthermore, spontaneous combustion damages coal resources and the ecological environment, particularly in Northwest my country, where large-scale coalfield spontaneous combustion zones have caused extremely serious environmental problems.

[0003] Coal spontaneous combustion is a complex physicochemical process involving multiple factors such as the chemical composition and physical structure of coal, and environmental conditions. Combustible substances in coal, such as carbon, sulfur, and nitrogen, react with oxygen under specific conditions, generating heat. When this heat accumulates to a certain level, the coal temperature rises, further accelerating the chemical reaction. This self-heating process cycles continuously, ultimately leading to spontaneous combustion. The kinetic mechanism of coal spontaneous combustion includes key aspects such as heat generation and accumulation, the path and rate of heat transfer, and the distribution and changes in temperature within the coal mass.

[0004] Polymer coal spontaneous combustion inhibitors are inhibitors prepared using high molecular polymer materials. They primarily inhibit the spontaneous combustion of coal through physical and chemical actions. Polymer inhibitors typically consist of polymers, special surfactants, and a small amount of additives. These components interact to form an inhibitory system with a stable structure and excellent performance.

[0005] Although polymeric coal spontaneous combustion inhibitors have shown promising application prospects in the prevention and control of coal spontaneous combustion, existing polymeric coal spontaneous combustion inhibitors still have some problems that limit their effectiveness and promotion in practical applications. As coal temperature rises, polymeric inhibitors are prone to pyrolysis, thus losing their inhibitory effect. Simultaneously, the pyrolysis process may release combustible gases, increasing the risk of coal spontaneous combustion. For example, some polymeric inhibitors decompose at high temperatures to produce small molecule compounds. These small molecule compounds not only fail to exert their inhibitory effect but may also become combustion promoters for coal spontaneous combustion. Some polymeric inhibitors have low inhibition efficiency during coal spontaneous combustion, failing to effectively suppress the process. This may be due to insufficient bonding strength between the inhibitor and the coal surface, or the inability of the effective components in the inhibitor to fully penetrate into the coal body, resulting in limited inhibitory effect. Based on this, the present invention provides a preparation process for a polymeric coal spontaneous combustion inhibitor. Summary of the Invention

[0006] To address the problems mentioned in the background section, this invention provides a preparation process for a polymer coal self-ignition inhibitor.

[0007] The present invention adopts the following technical solution:

[0008] A preparation process for a polymer coal self-ignition inhibitor includes the following steps:

[0009] S1. Disperse polydopamine microcapsules evenly in deionized water, add GMA-grafted CNC, and stir until uniform to obtain a mixture.

[0010] S2. Add acrylic acid and acrylamide to the mixture prepared in step S1 in sequence, followed by crosslinking agent and initiator. Stir under nitrogen protection. After reaction, a gel is formed. Immerse the gel in ethanol to replace the water. After freeze-drying, the polymer coal self-ignition inhibitor is obtained.

[0011] Furthermore, the weight ratio of the polydopamine microcapsules, deionized water, GMA-grafted CNC, acrylic acid, acrylamide, crosslinking agent, and initiator is (3-5):(50-60):(4-5):(14-16):(4-6):(0.5-0.7):(1-1.4).

[0012] Furthermore, the preparation method of the polydopamine microcapsules includes the following steps: mixing paraffin and stearic acid and stirring to form a homogeneous complex, cooling to room temperature, and pulverizing into powder for later use; dissolving the homogeneous complex powder in ethanol, adding it to an aqueous solution of sodium dodecyl sulfate, ultrasonically emulsifying to form an O / W emulsion, adding dopamine hydrochloride solution to the emulsion, stirring, centrifuging, washing, and drying to obtain the final product.

[0013] Furthermore, the weight ratio of the paraffin and stearic acid is (6-7):(3-4).

[0014] Further, the concentration of the aqueous solution of sodium dodecyl sulfate is 0.5-1 g / 100 mL; the concentration of the aqueous solution of dopamine hydrochloride is 2-3 mg / mL; and the ratio of the homogeneous complex powder, ethanol, aqueous solution of sodium dodecyl sulfate and aqueous solution of dopamine hydrochloride is (1-2) g : (10-20) mL : (100-110) mL : (85-95) mL.

[0015] Furthermore, the preparation method of the GMA-grafted CNC includes the following steps: dispersing cellulose nanocrystals (CNC) in deionized water, adding glycidyl methacrylate (GMA), reacting at 60-70°C for 6-8 hours, and obtaining the product after centrifugation and washing.

[0016] Furthermore, the ratio of the amount of cellulose nanocrystals, deionized water and glycidyl methacrylate is (5-7)g:(100-110)mL:(2-3)g.

[0017] Furthermore, the cellulose nanocrystals have a diameter of 10-20 nm and a length of 100-300 nm.

[0018] Furthermore, the crosslinking agent is N,N'-methylenebisacrylamide; and the initiator is ammonium persulfate.

[0019] Furthermore, the freeze-drying temperature is -45 to -55°C, and the time is 24-26 hours.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention utilizes polydopamine microcapsules as the core functional unit of the inhibitor, achieving a dual mechanism of phase change heat absorption and carbonization barrier to suppress coal spontaneous combustion by encapsulating paraffin / stearic acid phase change material. Paraffin and stearic acid, as phase change materials, absorb heat during coal spontaneous combustion, lowering the coal temperature. The polydopamine microcapsules, acting as an encapsulation layer, not only protect the phase change material from external environmental influences but also carbonize at high temperatures to form a barrier layer, preventing direct contact between oxygen and the coal, thus effectively inhibiting coal spontaneous combustion. The experimental results of Comparative Example 1 show a significant increase in CO concentration, verifying the importance of the microcapsules.

[0022] In this invention, GMA grafted with CNC enhances the crosslinking density of the gel network, thereby improving the thermal stability and mechanical strength of the inhibitor. Specifically, the GMA grafted with CNC forms a stronger interfacial bond with the polymer network, increasing the crosslinking points of the gel network and thus improving the overall strength and stability of the inhibitor. The experimental results of Comparative Example 2 (without CNC grafting) show an increase in CO concentration, indicating the enhancing effect of GMA grafted with CNC on the inhibitory performance.

[0023] In this invention, the choice of crosslinking agent directly affects the thermal stability of the inhibitor; N,N'-methylenebisacrylamide is superior to ethylene glycol dimethacrylate. Specifically, N,N'-methylenebisacrylamide, as a crosslinking agent, can form a more stable crosslinked structure, thus improving the thermal stability of the inhibitor. The experimental results of Comparative Example 3 show that the inhibitor using ethylene glycol dimethacrylate as a crosslinking agent has a lower initial decomposition temperature and lower carbon residue than the inhibitor using N,N'-methylenebisacrylamide.

[0024] In this invention, the freeze-drying temperature needs to be controlled between -45 and -55°C to ensure the uniformity of the porous structure. Freeze-drying at -45 to -55°C can form a more uniform and finer porous structure, which is beneficial for the penetration and coverage of the inhibitor. The experimental results of Comparative Example 5 show that the inhibitor obtained by low-temperature freeze-drying has better performance.

[0025] In this invention, the stability of the gel network is enhanced by optimizing the ratio of acrylic acid to acrylamide. Acrylamide forms a stronger network structure with monomers such as acrylic acid through hydrogen bonds, thereby improving the stability and inhibitory performance of the inhibitor. The experimental results of Comparative Example 6 show that the inhibitor without acrylamide has poor performance. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise specified, the raw materials used in this invention are all from commercially available conventional products.

[0028] Among them, paraffin wax: CAS No.: 64742-51-4, was purchased from Jinan Dehou Chemical Co., Ltd.

[0029] Example 1

[0030] A preparation process for a polymer coal self-ignition inhibitor includes the following steps:

[0031] (1) Preparation of polydopamine microcapsules: Paraffin and stearic acid were mixed and melted at 75°C for 1 hour to form a homogeneous complex. After cooling to room temperature, the mixture was pulverized into powder for later use. The homogeneous complex powder was dissolved in ethanol and added to an aqueous solution of sodium dodecyl sulfate with a concentration of 0.7 g / 100 mL. The mixture was emulsified by sonication at 300 W for 30 min to form an O / W emulsion. The pH of the emulsion was adjusted to 8.5. An aqueous solution of dopamine hydrochloride with a concentration of 2.5 mg / mL was added to the emulsion. The mixture was stirred at 200 rpm for 24 h, centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and dried at 60°C for 24 h to obtain the product. The weight ratio of paraffin and stearic acid was 6.5:3.5. The ratio of the homogeneous complex powder, ethanol, aqueous solution of sodium dodecyl sulfate, and aqueous solution of dopamine hydrochloride was 1.5 g:15 mL:105 mL:90 mL.

[0032] (2) The preparation method of GMA-grafted CNC includes the following steps: dispersing cellulose nanocrystals (CNC) in deionized water, adding glycidyl methacrylate (GMA), reacting at 65°C for 7 hours, the ratio of cellulose nanocrystals, deionized water and glycidyl methacrylate is 6g:105mL:2.5g; centrifuging at 6000rpm for 10min, washing with deionized water, and drying at 50°C to obtain the cellulose nanocrystals; the average diameter of the cellulose nanocrystals is 15nm and the average length is 200nm.

[0033] (3) Disperse polydopamine microcapsules in deionized water and sonicate for 30 min at 200 W to achieve uniform dispersion. Add GMA-grafted CNC and stir at 300 rpm until uniform to obtain a mixture. Add acrylic acid and acrylamide to the prepared mixture in sequence, followed by crosslinking agent N,N'-methylenebisacrylamide and initiator ammonium persulfate. Stir magnetically at 60°C and 200 rpm for 3 hours under nitrogen protection. After reaction, adjust the pH of the system to 7.0 with 10% NaOH aqueous solution. After standing for 20 h, a gel is formed. Immerse the gel in ethanol to replace the water and freeze-dry at -50°C for 25 h to obtain the inhibitor. The weight ratio of polydopamine microcapsules, deionized water, GMA-grafted CNC, acrylic acid, acrylamide, crosslinking agent and initiator is 4:55:4.5:15:5:0.6:1.2.

[0034] Example 2

[0035] A preparation process for a polymer coal self-ignition inhibitor includes the following steps:

[0036] (1) Preparation of polydopamine microcapsules: Paraffin and stearic acid were mixed and melted at 75°C for 1 hour to form a homogeneous complex. After cooling to room temperature, the mixture was pulverized into powder for later use. The homogeneous complex powder was dissolved in ethanol and added to an aqueous solution of sodium dodecyl sulfate with a concentration of 0.5 g / 100 mL. The mixture was emulsified by sonication at 300 W for 30 min to form an O / W emulsion. The pH of the emulsion was adjusted to 8.5. An aqueous solution of dopamine hydrochloride with a concentration of 2 mg / mL was added to the emulsion. The mixture was stirred at 200 rpm for 24 h, centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and dried at 60°C for 24 h to obtain the product. The weight ratio of paraffin to stearic acid was 6:4. The ratio of the homogeneous complex powder, ethanol, aqueous solution of sodium dodecyl sulfate, and aqueous solution of dopamine hydrochloride was 1 g: 10 mL: 100 mL: 85 mL.

[0037] (2) The preparation method of GMA-grafted CNC includes the following steps: cellulose nanocrystals are dispersed in deionized water, glycidyl methacrylate is added, and the reaction is carried out at 60°C for 6 hours. The ratio of cellulose nanocrystals, deionized water and glycidyl methacrylate is 5g:100mL:2g. After centrifugation at 6000rpm for 10min, the nanocrystals are washed with deionized water and dried at 50°C. The average diameter of the cellulose nanocrystals is 10nm and the average length is 100nm.

[0038] (3) The polydopamine microcapsules were dispersed in deionized water and ultrasonically treated for 30 min at a power of 200W to achieve uniform dispersion. GMA-grafted CNC was added and stirred at 300 rpm until uniform to obtain a mixture. Acrylic acid and acrylamide were added to the prepared mixture in sequence, followed by crosslinking agent N,N'-methylenebisacrylamide and initiator ammonium persulfate. The mixture was magnetically stirred at 60°C and 200 rpm for 3 hours under nitrogen protection. After the reaction, the pH of the system was adjusted to 7.0 with 10% NaOH aqueous solution. After standing for 20 h, a gel was formed. The gel was immersed in ethanol to replace the water and freeze-dried at -45°C for 24 h to obtain the inhibitor. The weight ratio of polydopamine microcapsules, deionized water, GMA-grafted CNC, acrylic acid, acrylamide, crosslinking agent and initiator was 3:50:4:14:4:0.5:1.

[0039] Example 3

[0040] A preparation process for a polymer coal self-ignition inhibitor includes the following steps:

[0041] (1) Preparation of polydopamine microcapsules: Paraffin and stearic acid were mixed and melted at 75°C for 1 hour to form a homogeneous complex. After cooling to room temperature, the mixture was pulverized into powder for later use. The homogeneous complex powder was dissolved in ethanol and added to an aqueous solution of sodium dodecyl sulfate with a concentration of 1 g / 100 mL. The mixture was then emulsified by sonication at 300 W for 30 min to form an O / W emulsion. The pH of the emulsion was adjusted to 8.5. An aqueous solution of dopamine hydrochloride with a concentration of 3 mg / mL was added to the emulsion. The mixture was stirred at 200 rpm for 24 hours, centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and dried at 60°C for 24 hours to obtain the product. The weight ratio of paraffin to stearic acid was 7:3. The ratio of the homogeneous complex powder, ethanol, aqueous solution of sodium dodecyl sulfate, and aqueous solution of dopamine hydrochloride was 2 g: 20 mL: 110 mL: 95 mL.

[0042] (2) The preparation method of GMA-grafted CNC includes the following steps: cellulose nanocrystals are dispersed in deionized water, glycidyl methacrylate is added, and the reaction is carried out at 70°C for 8 hours. The ratio of cellulose nanocrystals, deionized water and glycidyl methacrylate is 7g:110mL:3g. After centrifugation at 6000rpm for 10min, the nanocrystals are washed with deionized water and dried at 50°C. The average diameter of the cellulose nanocrystals is 20nm and the average length is 300nm.

[0043] (3) Polydopamine microcapsules were dispersed in deionized water and ultrasonically treated for 30 min at 200 W to achieve uniform dispersion. GMA-grafted CNC was added and stirred at 300 rpm until uniform to obtain a mixture. Acrylic acid and acrylamide were added to the prepared mixture in sequence, followed by crosslinking agent N,N'-methylenebisacrylamide and initiator ammonium persulfate. The mixture was magnetically stirred at 60°C and 200 rpm for 3 hours under nitrogen protection. After the reaction, the pH of the system was adjusted to 7.0 with 10% NaOH aqueous solution. After standing for 20 h, a gel was formed. The gel was immersed in ethanol to replace the water and freeze-dried at -55°C for 26 h to obtain the inhibitor. The weight ratio of polydopamine microcapsules, deionized water, GMA-grafted CNC, acrylic acid, acrylamide, crosslinking agent and initiator was 5:60:5:16:6:0.7:1.4.

[0044] Example 4

[0045] A preparation process for a polymer coal self-ignition inhibitor includes the following steps:

[0046] (1) Preparation of polydopamine microcapsules: Paraffin and stearic acid were mixed and melted at 75°C for 1 hour to form a homogeneous complex. After cooling to room temperature, the mixture was pulverized into powder for later use. The homogeneous complex powder was dissolved in ethanol and added to an aqueous solution of sodium dodecyl sulfate with a concentration of 0.5 g / 100 mL. The mixture was emulsified by sonication at 300 W for 30 min to form an O / W emulsion. The pH of the emulsion was adjusted to 8.5. An aqueous solution of dopamine hydrochloride with a concentration of 3 mg / mL was added to the emulsion. The mixture was stirred at 200 rpm for 24 h, centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and dried at 60°C for 24 h to obtain the product. The weight ratio of paraffin to stearic acid was 6:4. The ratio of the homogeneous complex powder, ethanol, aqueous solution of sodium dodecyl sulfate, and aqueous solution of dopamine hydrochloride was 1 g: 10 mL: 110 mL: 95 mL.

[0047] (2) The preparation method of GMA-grafted CNC includes the following steps: cellulose nanocrystals are dispersed in deionized water, glycidyl methacrylate is added, and the reaction is carried out at 70°C for 6 hours. The ratio of cellulose nanocrystals, deionized water and glycidyl methacrylate is 5g:110mL:3g. After centrifugation at 6000rpm for 10min, the nanocrystals are washed with deionized water and dried at 50°C. The average diameter of the cellulose nanocrystals is 10nm and the average length is 300nm.

[0048] (3) Polydopamine microcapsules were dispersed in deionized water and ultrasonically treated for 30 min at 200 W to achieve uniform dispersion. GMA-grafted CNC was added and stirred at 300 rpm until uniform to obtain a mixture. Acrylic acid and acrylamide were added to the prepared mixture in sequence, followed by crosslinking agent N,N'-methylenebisacrylamide and initiator ammonium persulfate. The mixture was magnetically stirred at 60°C and 200 rpm for 3 hours under nitrogen protection. After the reaction, the pH of the system was adjusted to 7.0 with 10% NaOH aqueous solution. After standing for 20 h, a gel was formed. The gel was immersed in ethanol to replace the water and freeze-dried at -55°C for 24 h to obtain the inhibitor. The weight ratio of polydopamine microcapsules, deionized water, GMA-grafted CNC, acrylic acid, acrylamide, crosslinking agent and initiator was 3:60:4:16:4:0.7:1.

[0049] Comparative Example 1

[0050] Based on Example 1, adjustments were made, but unlike Example 1, no polydopamine microcapsules were added in Comparative Example 1.

[0051] Comparative Example 2

[0052] Based on Example 1, adjustments were made. Unlike Example 1, Comparative Example 2 used unmodified cellulose nanocrystals (i.e., ungrafted glycidyl methacrylate).

[0053] Comparative Example 3

[0054] Based on Example 1, adjustments were made. Unlike Example 1, in step 3 of Comparative Example 3, the crosslinking agent was replaced with ethylene glycol dimethacrylate (instead of N,N'-methylenebisacrylamide).

[0055] Comparative Example 4

[0056] Based on Example 1, adjustments were made, but unlike Example 1, Comparative Example 4 did not add a CNC grafted with GMA.

[0057] Comparative Example 5

[0058] Based on Example 1, adjustments were made. Unlike Example 1, the freeze-drying temperature in step 3 of Comparative Example 5 was adjusted to -30°C.

[0059] Comparative Example 6

[0060] Based on Example 1, adjustments were made. Unlike Example 1, in Comparative Example 6, acrylamide was not added in step 3; only acrylic monomer was used. The other steps were the same.

[0061] Comparative Example 7

[0062] Based on Example 1, adjustments were made. Unlike Example 1, the ratio of paraffin to stearic acid in step 1 of Comparative Example 7 was changed to 8:2 (originally 6.5:3.5).

[0063] Experimental example: The polymer coal self-ignition inhibitors prepared in Examples 1-4 and Comparative Examples 1-7 were tested as follows.

[0064] Preparation of coal samples: First, take lignite with an average particle size of 30 mesh and dry it to constant weight at a temperature of 50℃ for later use.

[0065] Preparation of inhibited coal sample: Take 9g of polymer coal self-ignition inhibitor, dissolve it in a 30mL volumetric flask to prepare a dilution solution, then measure 12mL of the dilution solution and add it to 30g of dried lignite sample and stir evenly. Dry the sample at 50℃ and test it after the coal sample reaches constant weight.

[0066] 1. Resistance performance test:

[0067] The inhibition performance test method of polymer-based coal self-ignition inhibitor is as follows: Weigh 25g of coal sample into a sample tube, check the airtightness of the system, and then place it in a programmed temperature riser. Dry air is introduced into the sample tube at a flow rate of 100mL / min. The programmed temperature riser is heated to 100℃ at a rate of 2.5℃ / min, and then sampled every 10min until the total time reaches 150min. The CO content generated by the coal sample is determined by WT-80-CO analysis produced by Shanghai Yiren Electric Co., Ltd. The average CO concentration is used to reflect the inhibition performance of the polymer-based inhibitor.

[0068] Blank control: 25g of dried lignite was weighed and tested using the same inhibition performance method as described above. The measured CO concentration was 122ppm.

[0069] Comparison with existing technology: 25g of dried lignite was weighed and tested using the same inhibition performance method as described above, except that the inhibitor was replaced with the existing commercial inhibitor FR-757. The measured CO concentration was 85ppm.

[0070] 2. Thermogravimetric analysis

[0071] Instrument: Thermogravimetric analyzer (TGA, TA Instruments Q50);

[0072] Parameter settings: The amount of each inhibited coal sample used is 10mg (±0.01mg), under nitrogen atmosphere, the flow rate is set to 50mL / min, the heating rate is 10℃ / min, and the heating range is 25-700℃;

[0073] The residual carbon rate is calculated as follows: Residual carbon rate (%) = Remaining mass at 700℃ / Initial sample mass × 100%;

[0074] The test results are shown in Table 1:

[0075] Table 1: Effect Test

[0076] Example 1 46 325 42.5 Example 2 49 320 39.7 Example 3 56 312 38.9 Example 4 53 316 39.4 Comparative Example 1 82 280 28.3 Comparative Example 2 68 305 36.1 Comparative Example 3 61 315 38.9 Comparative Example 4 75 290 31.7 Comparative Example 5 59 312 39.8 Comparative Example 6 72 298 33.6 Comparative Example 7 65 298 34.2

[0077] The above data show that Example 1 (46 ppm) is significantly superior to the blank control (122 ppm) and the prior art control (85 ppm), indicating its excellent inhibitory effect. The CO concentration in Comparative Example 1 increased to 82 ppm, indicating that the microcapsules delay the exothermic reaction of coal oxidation by encapsulating the paraffin / stearic acid phase change material. The CO concentration in Comparative Example 2 increased to 68 ppm, indicating that GMA grafting enhances the interfacial bonding between the CNC and the polymer network, improving the inhibitor coverage efficiency. The CO concentration in Comparative Example 5 (58 ppm) is slightly higher than that in Example 1, indicating that low-temperature freeze-drying forms a more uniform porous structure, enhancing the inhibitor permeability. The CO concentration in Comparative Example 6 (72 ppm) indicates that acrylamide enhances the gel network through hydrogen bonding, improving the inhibitor stability.

[0078] Furthermore, Example 1 exhibited the highest initial decomposition temperature, while Comparative Example 1 showed the lowest, indicating that the polydopamine microcapsules and GMA-grafted CNC synergistically enhanced thermal stability. Comparative Example 3 had an initial decomposition temperature of 315°C and a residual carbon rate of 38.9%, demonstrating that the crosslinking effect of N,N'-methylenebisacrylamide was superior to that of ethylene glycol dimethacrylate. Comparative Example 7 had an initial decomposition temperature of 298°C and a residual carbon rate of 34.2%, indicating that an excessively high paraffin content led to a decrease in microcapsule encapsulation efficiency and premature release of the phase change material. Moreover, Example 1 showed significantly higher temperatures than the other groups, while Comparative Example 1 had the lowest, further validating the carbonized framework and CNC reinforcement effect of the polydopamine microcapsules.

[0079] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0080] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A preparation process for a polymer coal self-ignition inhibitor, characterized in that, Includes the following steps: S1. Disperse polydopamine microcapsules evenly in deionized water, add GMA-grafted CNC, and stir until uniform to obtain a mixture. S2. Add acrylic acid and acrylamide to the mixture prepared in step S1 in sequence, then add crosslinking agent and initiator, stir under nitrogen protection, and a gel is formed after reaction. Immerse the gel in ethanol to replace water, and freeze dry to obtain the polymer coal self-ignition inhibitor. The weight ratio of the polydopamine microcapsules, deionized water, GMA-grafted CNC, acrylic acid, acrylamide, crosslinking agent, and initiator is (3-5):(50-60):(4-5):(14-16):(4-6):(0.5-0.7):(1-1.4); the crosslinking agent is N,N'-methylenebisacrylamide. The preparation method of the polydopamine microcapsules includes the following steps: paraffin and stearic acid are mixed and melted to form a homogeneous complex, cooled to room temperature, and pulverized into powder for later use; the homogeneous complex powder is dissolved in ethanol, added to an aqueous solution of sodium dodecyl sulfate, and ultrasonically emulsified to form an O / W emulsion; dopamine hydrochloride solution is added to the emulsion, and after stirring, centrifugation, washing, and drying, the product is obtained; the weight ratio of paraffin and stearic acid is (6-7):(3-4).

2. The preparation process of a polymer coal self-ignition inhibitor according to claim 1, characterized in that, The concentration of the sodium dodecyl sulfate aqueous solution is 0.5-1 g / 100 mL; the concentration of the dopamine hydrochloride solution is 2-3 mg / mL; the ratio of the homogeneous complex powder, ethanol, sodium dodecyl sulfate aqueous solution and dopamine hydrochloride aqueous solution is (1-2) g : (10-20) mL : (100-110) mL : (85-95) mL.

3. The preparation process of a polymer coal self-ignition inhibitor according to claim 1, characterized in that, The preparation method of the GMA-grafted CNC includes the following steps: dispersing cellulose nanocrystals in deionized water, adding glycidyl methacrylate, reacting at 60-70℃ for 6-8 hours, and obtaining the product after centrifugation and washing.

4. The preparation process of a polymer coal self-ignition inhibitor according to claim 3, characterized in that, The ratio of the amount of cellulose nanocrystals, deionized water and glycidyl methacrylate is (5-7) g: (100-110) mL: (2-3) g.

5. The preparation process of a polymer coal self-ignition inhibitor according to claim 3, characterized in that, The cellulose nanocrystals have a diameter of 10-20 nm and a length of 100-300 nm.

6. The preparation process of a polymer coal self-ignition inhibitor according to claim 1, characterized in that, The initiator is ammonium persulfate.

7. The preparation process of a polymer coal self-ignition inhibitor according to claim 1, characterized in that, The freeze-drying temperature is -45~-55℃, and the time is 24-26h.