Silicon-containing modified polycarboxylate dispersant with macromolecular large branched chain

Abstract

The invention discloses a silicon-containing modified polycarboxylate dispersant with a macromolecular large branch chain and a preparation method of the silicon-containing modified polycarboxylate dispersant, and relates to the technical field of polycarboxylate dispersant modification.The preparation method comprises the steps that allyl alcohol polyoxyethylene ether, sodium p-styrenesulfonate and acrylic acid serve as raw materials; 3-(methacryloyloxy) propyl trimethoxy silane is introduced as a silane coupling agent, and a silane graft modified polycarboxylate dispersing agent is prepared by virtue of a free radical polymerization process; wherein the dosage of each raw material is as follows: 20% of allyl alcohol polyoxyethylene ether and 3.5% of 3-(methacryloyloxy) propyltrimethoxysilane, and the molar ratio of acrylic acid to sodium p-styrenesulfonate is always 2: 1; the polycarboxylate dispersing agent achieves the purpose of enhancing the anchoring and dispersing effects of the dispersing agent, and provides reference for synthesis of a high-performance polycarboxylic acid type coal water slurry dispersing agent and preparation of high-performance coal water slurry.

Description

Technical Field

[0001] This invention relates to the field of polycarboxylate dispersant modification technology, specifically to a silicon-modified polycarboxylate dispersant with large molecular branches. Background Technology

[0002] Polycarboxylate dispersants, with their flexible and tunable molecular structure, possess outstanding advantages such as simple synthesis process, environmental friendliness, and excellent dispersion performance. Their comprehensive performance is significantly better than that of traditional dispersants, and they have been applied on a large scale in multiple industrial fields such as cement, coatings, dyes, and pesticides. In particular, they have demonstrated key value in the field of coal-water slurry preparation—not only can they be customized for specific coal types based on controllable molecular structures, but their simple synthesis process also provides a solid guarantee for industrial production and economic application.

[0003] When used as a dispersant in coal-water slurry, polycarboxylate molecules exhibit a typical comb-like structure. Their main chain carries polar active groups such as carboxyl, hydroxyl, and sulfonic acid groups, which can interact with coal particles through various mechanisms. The side chains are long-chain hydrophilic groups that, with their flexible structure, adsorb onto the surface of coal powder and form a solvation layer, constructing a three-dimensional network structure to enhance steric hindrance and ensure uniform dispersion of coal particles. Furthermore, by precisely controlling parameters such as the type and number of functional groups, and the structure and length of the side chains, their performance in adapting to the physicochemical properties of different coal types can be further optimized.

[0004] With technological advancements and increasingly stringent environmental requirements, the variety of polycarboxylate dispersants is constantly expanding. Among them, silicon-containing polycarboxylate dispersants, prepared by modifying traditional structures with silicon-containing monomers, have shown broad application potential in fields such as coal-water slurry. Unlike traditional polycarboxylate dispersants, which rely on horizontal multi-point physical adsorption through hydrophobic interactions, electrostatic interactions, and hydrogen bonds, silicon-modified products can introduce silane groups through silane coupling agents. The silanol groups generated by the hydrolysis of these groups can undergo condensation reactions with the hydroxyl groups on the surface of coal particles, forming stable Si–O–C covalent bonds to achieve chemical adsorption and significantly enhance interfacial anchoring ability. At the same time, silane coupling agents can promote intermolecular coupling of polycarboxylate molecules, increasing the "dispersant bridge" between coal particles and further improving the stability of coal-water slurry. However, it should be noted that excessive coupling agent can lead to weakened dispersion and enhanced flocculation, which may cause slurry instability. Therefore, the appropriate introduction of silicon-containing monomers is key to improving dispersion performance.

[0005] Patent CN112250799A discloses a method for preparing organosilicon-modified polycarboxylate dispersants. Using small-molecule unsaturated carboxylic acids and unsaturated polyether compounds as raw materials, the product is obtained through solution copolymerization, exhibiting advantages such as low production cost and low surface tension (20-28 mN / m). Other studies have used various polyoxyethylene ethers as macromolecular raw materials, determining the optimal feed ratio to synthesize silicon-modified dispersants that demonstrate excellent wettability and dispersion stability. Still other studies have introduced γ-methacryloyloxypropyltrimethoxysilane into the polycarboxylic acid backbone through free radical copolymerization, resulting in silane-modified water-reducing agents with significantly enhanced adsorption capacity in cement pastes, effectively reducing the system's yield stress and plastic viscosity.

[0006] Despite the significant potential of silicon-containing polycarboxylate dispersants, their research and application in the field of coal-water slurry are still in the initial stage and require systematic exploration. Summary of the Invention

[0007] The purpose of this invention is to provide a silicon-modified polycarboxylate dispersant with large molecular branches to solve the problems that existing polycarboxylate dispersants have limited interfacial anchoring ability for coal particles, and that silicon-containing polycarboxylate dispersants are difficult to fully adapt to the performance and environmental protection requirements of coal-water slurry.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] According to the first aspect of this disclosure, a silicon-modified polycarboxylate dispersant with large molecular branches is also proposed, the structural formula of which is:

[0010] .

[0011] According to a second aspect of this disclosure, a method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches is also provided, comprising the following steps:

[0012] S1. Take a 250mL four-necked flask, wash it and let it dry. At room temperature, add isopropanol, allyl alcohol polyoxyethylene ether, sodium styrene sulfonate and purified water to the 250mL four-necked flask.

[0013] S2. Take a 50mL beaker and put acrylic acid, mercaptopropionic acid, 3-(methacryloyloxy)propyltrimethoxysilane and purified water into the beaker. Add a magnetic stir bar and stir with a magnetic stirrer until completely dissolved. Transfer to a clean and dry dropper bottle for later use.

[0014] S3. Weigh out the initiator ammonium persulfate and sodium bisulfite, dissolve them in pure water, and set aside.

[0015] S4. Place the four-necked flask containing the reagent into an oil bath, reflux it, and add 3.3 mL of ammonium persulfate solution as an initiator to start the reaction. Control the solution in the dropping bottle to be evenly added to the flask.

[0016] After the phase reaction was completed, the solution was kept at a constant temperature for another 1 hour to obtain a slightly yellow, transparent, homogeneous solution.

[0017] S5. Transfer the slightly yellow transparent homogeneous solution to a 250 mL round-bottom flask, connect it to a rotary evaporator, and rotary evaporate until the droplet rate in the Soxhlet extractor drops to <1 drop / 5 min, to obtain a viscous slightly yellow transparent substance.

[0018] By regulating alkaline hydrolysis, the siloxane groups are hydrolyzed and condensed to form a three-dimensional network structure, ultimately yielding an orange-yellow homogeneous viscous product, which is the prepared silicon-modified polycarboxylate dispersant.

[0019] Furthermore, in step S1, the allyl alcohol polyoxyethylene ether has a molecular weight of 1000 and is used in an amount of 20% by mass.

[0020] Furthermore, the sodium styrene sulfonate in step S1 and the acrylic acid in step S2 are in a molar ratio of 1:2.

[0021] Furthermore, in step S2, the 3-(methacryloyloxy)propyltrimethoxysilane is a silane coupling agent, and its dosage is 3.5% by mass.

[0022] Furthermore, in step S3, the ammonium persulfate solution serves as an initiator, accounting for 4% by mass.

[0023] Furthermore, in step S3, the sodium bisulfite solution serves as an initiator, accounting for 3% by mass.

[0024] Furthermore, in step S4, the temperature inside the four-necked flask is heated to 70°C in an oil bath.

[0025] Furthermore, in step S4, when adding 3.3 mL of initiator solution to start the reaction, the solution in the dropping bottle is controlled to be evenly added to the flask. 200 μL of initiator ammonium persulfate solution is added every 4 min, and 200 μL of sodium bisulfite solution is added every 5 min, with both added over 2 h.

[0026] Further, in step S5, the alkaline water is a sodium hydroxide solution with a concentration of 10 mol / L, and the pH is titrated to 9-10.

[0027] Compared with existing technologies, this invention provides a silicon-modified polycarboxylate dispersant with large molecular branches. Using acrylic acid, sodium styrene sulfonate, allyl alcohol polyoxyethylene ether, and 3-(methacryloyloxy)propyltrimethoxysilane as raw materials, it is green and clean. The amount of silicon-containing polycarboxylate dispersant added is 0.3% of the dry coal, exhibiting good pseudoplastic characteristics. Its effect is superior to the widely used sodium naphthalene sulfonate formaldehyde condensate dispersant, and its product is easy to purify. The overall synthesis method is simple, and the reaction conditions are easy to control. The added silane coupling agent enhances the adsorption of the dispersant, significantly improving the slurry preparation efficiency and quality of coal-water slurry, providing a new technical solution for the efficient and clean utilization of coal resources. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0029] Figure 1 The diagram shows the structural formula of the silicon-modified polycarboxylate dispersant provided in the embodiments of the present invention. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] The raw materials and reagents used in this invention are: allyl alcohol polyoxyethylene ether; acrylic acid; sodium styrene sulfonate; 3-(methacryloyloxy)propyltrimethoxysilane; isopropanol; ammonium persulfate; sodium bisulfite; mercaptopropionic acid; and sodium hydroxide.

[0032] By using allyl alcohol polyoxyethylene ether as an ether macromonomer, sodium styrene sulfonate as a rigid framework building unit, acrylic acid as an anionic functional monomer, and 3-(methacryloyloxy)propyltrimethoxysilane as a silane coupling agent, a silicon-modified polycarboxylate dispersant was successfully constructed using a free radical polymerization process.

[0033] This invention provides a method for preparing a silicon-modified polycarboxylate dispersant, characterized in that the method comprises:

[0034] Example 1

[0035] Example 1 illustrates the preparation method of the silicon-modified polycarboxylate dispersant of the present invention and the silicon-modified polycarboxylate dispersant prepared by the method.

[0036] The silicon-modified polycarboxylate dispersant of this embodiment is polymerized from the following components, with a total raw material mass of 35g and the amounts of each component as follows:

[0037] Allyl alcohol polyoxyethylene ether has a molecular weight of 1000 and is used at a mass percentage of 20%.

[0038] Acrylic acid:sodium styrene sulfonate in a molar ratio of 2:1;

[0039] 3-(methacryloyloxy)propyltrimethoxysilane is a silane coupling agent, used at a mass percentage of 3.5%.

[0040] The ratio of ammonium persulfate to sodium bisulfite was always maintained at 4:3, with ammonium persulfate accounting for 4% of the initiator by mass and sodium bisulfite accounting for 3% of the initiator by mass.

[0041] As a preferred embodiment, the preparation method of the coal-water slurry dispersant provided by the present invention includes the following steps:

[0042] Step 1: Take a 250 mL four-necked flask, wash it and let it dry. At room temperature, add isopropanol, allyl alcohol polyoxyethylene ether, sodium styrene sulfonate and purified water to the 250 mL four-necked flask.

[0043] Step 2: Take a 50 mL beaker and put acrylic acid, mercaptopropionic acid, 3-(methacryloyloxy)propyltrimethoxysilane and purified water into the beaker. Add a magnetic stir bar and stir with a magnetic stirrer until completely dissolved. Transfer to a clean and dry dropper bottle for later use.

[0044] Step 3: Weigh out the initiator ammonium persulfate and sodium bisulfite, dissolve them in purified water, and set aside for later use;

[0045] Step 4: Connect the experimental apparatus and place the four-necked flask containing the reagents into an oil bath (temperature controlled at 70℃). Reflux the solution and add 3.3 mL of ammonium persulfate solution as the initiator to begin the reaction. Control the solution in the dropping bottle to be added evenly to the flask (the solution in the dropping bottle should be added completely over 2 hours). Add 200 μL of ammonium persulfate solution every 4 minutes and 200 μL of sodium bisulfite solution every 5 minutes, both over 2 hours. After the initial reaction is complete, continue to maintain the temperature for 1 hour to obtain a slightly yellow, transparent, homogeneous solution.

[0046] Step 5: Transfer the liquid obtained in Step 4 to a 250 mL round-bottom flask, connect it to a rotary evaporator, and evaporate until the droplet rate in the Soxhlet extractor drops to <1 drop / 5 min, obtaining a viscous, slightly yellow, transparent substance. Subsequently, alkaline hydrolysis (titration of pH to 9-10 with 10 mol / L NaOH solution) is used to induce the hydrolysis and condensation of siloxane groups to form a three-dimensional network structure, ultimately obtaining an orange-yellow homogeneous viscous product, which is the prepared silicon-modified polycarboxylate dispersant.

[0047] Example 2

[0048] In Example 2, except that the reaction dropping time in step four was changed from 2 h to 1 h, the same raw material composition and dosage as in Example 1 were used to prepare the coal-water slurry dispersant of Example 2.

[0049] Example 3

[0050] In Example 3, except that the reaction dripping time in step four was changed from 2 h to 4 h, the same raw material composition and dosage as in Example 1 were used to prepare the coal-water slurry dispersant of Example 3.

[0051] Example 4

[0052] In Example 4, except that the amount of ammonium persulfate initiator in step three is 3% (the ratio of ammonium persulfate to sodium bisulfite is always maintained at 4:3), the same raw material components and methods as in Example 1 are used to prepare the coal-water slurry dispersant of Example 4.

[0053] Example 5

[0054] In Example 5, except that the amount of ammonium persulfate initiator in step three is 5% (the ratio of ammonium persulfate to sodium bisulfite is always maintained at 4:3), the same raw material components and methods as in Example 1 are used to prepare the coal-water slurry dispersant of Example 5.

[0055] Example 6

[0056] In Example 6, except that the oil bath temperature parameter in step four is 60°C, the same amount of raw material components as in Example 1 are used to prepare the coal-water slurry dispersant of Example 6.

[0057] The specific steps are shown in Table 1 below:

[0058] Table 1

[0059]

[0060] Comparative Example

[0061] In the comparative example, NSF was used as a dispersant to prepare coal-water slurry.

[0062] The basic parameters of the polycarboxylate-based coal-water slurry dispersants in the examples and comparative examples are compared in Table 2 below:

[0063] Table 2

[0064]

[0065] In summary, this invention designs a silicon-containing polycarboxylate dispersant and uses it as an additive in the preparation of Shaanxi coal water-coal slurry, comparing the slurry-forming effects of slurries with different dispersants. By adding a silane coupling agent (KH-570), the anchoring and dispersing effects of the dispersant are strengthened, providing valuable reference for the production of high-performance dispersants and the preparation of high-performance water-coal slurry in the process of synthesizing polycarboxylate-type water-coal slurry dispersants. With the increasing demands on the performance of water-coal slurry, silicon-containing polycarboxylate dispersants are expected to be further optimized through molecular design and synthesis processes to develop products with superior performance and greater adaptability. Meanwhile, under increasingly stringent environmental protection requirements, the development of green and biodegradable silicon-containing polycarboxylate dispersants is also an important future development direction.

[0066] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A silicon-modified polycarboxylate dispersant with large molecular branches, characterized in that, Its structural formula is: 。 2. A method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches, characterized in that, Includes the following steps: S1. Take a 250 mL four-necked flask, wash it and let it dry. At room temperature, add isopropanol, allyl alcohol polyoxyethylene ether, sodium styrene sulfonate and purified water to the 250 mL four-necked flask. S2. Take a 50 mL beaker and put acrylic acid, mercaptopropionic acid, 3-(methacryloyloxy)propyltrimethoxysilane and purified water into the beaker. Add a magnetic stir bar and stir with a magnetic stirrer until completely dissolved. Transfer to a clean and dry dropper bottle for later use. S3. Weigh out the initiator ammonium persulfate and sodium bisulfite, dissolve them in pure water, and set aside. S4. Place the four-necked flask containing the reagent into an oil bath, reflux it, and add 3.3 mL of ammonium persulfate solution as an initiator to start the reaction. Control the solution in the dropping bottle to be evenly added to the flask. After the phase reaction was completed, the mixture was kept at a constant temperature for another 1 h to obtain a slightly yellow, transparent, homogeneous solution. S5. Transfer the slightly yellow transparent homogeneous solution to a 250 mL round-bottom flask, connect it to a rotary evaporator, and rotary evaporate until the droplet rate in the Soxhlet extractor drops to <1 drop / 5 min, to obtain a viscous slightly yellow transparent substance. By regulating alkaline hydrolysis, the siloxane groups are hydrolyzed and condensed to form a three-dimensional network structure, ultimately yielding an orange-yellow homogeneous viscous product, which is the prepared silicon-modified polycarboxylate dispersant.

3. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, In step S1, the allyl alcohol polyoxyethylene ether has a molecular weight of 1000 and is used in an amount of 20% by mass.

4. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, The sodium styrene sulfonate in step S1 and the acrylic acid in step S2 are in a molar ratio of 1:

2.

5. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, In step S2, the 3-(methacryloyloxy)propyltrimethoxysilane is a silane coupling agent, and its dosage is 3.5% by mass.

6. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, In step S3, the ammonium persulfate solution is used as an initiator, accounting for 4% by mass.

7. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, In step S3, the sodium bisulfite solution is used as an initiator, accounting for 3% by mass.

8. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, In step S4, the temperature inside the four-necked flask is heated to 70°C in an oil bath.

9. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, In step S4, when 3.3 mL of initiator solution is added to start the reaction, the solution in the dropping bottle is controlled to be evenly added to the flask. 200 μL of initiator ammonium persulfate solution is added every 4 min, and 200 μL of sodium bisulfite solution is added every 5 min. Both are added in 2 h.

10. The method for preparing a silicon-modified polycarboxylate dispersant with large molecular branches according to claim 2, characterized in that, In step S5, the alkaline water is a sodium hydroxide solution with a concentration of 10 mol / L, and the pH is titrated to 9-10.

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