Preparation method of sulfonated styrene maleic anhydride acrylic grafted polyethylene glycol monomethyl ether dispersant and application thereof in self-dispersed carbon black

Abstract

This invention discloses a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant, its preparation method, and its application in highly dispersible carbon black, belonging to the field of fine chemical technology. This invention uses RAFT polymerization to prepare a styrene-maleic anhydride-acrylic acid copolymer, followed by sulfonation treatment. The sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant is prepared by polymerizing the sulfonated styrene-maleic anhydride-acrylic acid with polyethylene glycol monomethyl ether. The dispersant prepared by this invention exhibits good dispersibility and dispersion stability, and can be well applied in complex application environments with high electrolytes and strong alkalinity (such as viscose spinning solutions). By adding the prepared dispersant during the water-cooling stage of carbon black formation, carbon black with good dispersibility is successfully prepared. The carbon black slurry prepared by this invention can achieve an ultrafine particle size of D99≤500 nm with only gentle stirring and short-term grinding.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically relating to a method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black. Background Technology

[0002] Carbon black, as a high-performance and inexpensive black pigment, is widely used in various industrial fields such as textiles, coatings, and rubber. Especially in the black spinning of viscose fibers, the addition of carbon black is crucial for achieving a durable and uniform dyeing effect. However, the inherent high specific surface area and hydrophobicity of carbon black result in strong van der Waals forces between its particles, making it prone to irreversible aggregation and the formation of hard aggregates. This poses a significant challenge to its uniform dispersion in various media.

[0003] Traditional carbon black industrial production is mainly based on the incomplete combustion or thermal cracking of hydrocarbons, followed by quenching (water cooling) to terminate the reaction and collect the products. This process results in the primary carbon black particles having a chemically inert and hydrophobic surface, essentially making them prone to agglomeration. To improve the agglomeration characteristics of carbon black and prepare a well-dispersible carbon black application system, existing technologies generally employ a "post-processing" approach to prepare carbon black slurries or masterbatches. This involves first producing powdered carbon black products, and then, before use, attempting to redisperse them in water or other solvents through high-intensity physical grinding (such as sand milling or ball milling) with the aid of chemical dispersants to create slurries or masterbatches. However, this "agglomerate first, then disperse" post-processing approach generally suffers from inherent drawbacks such as low energy efficiency, equipment damage, incomplete coating, and performance bottlenecks. For example, re-dispersing already agglomerated, hard carbon black lumps requires high-intensity grinding, resulting in enormous energy consumption. High-intensity grinding causes severe wear on equipment and may introduce metallic impurities. Adding dispersants later makes it difficult to fully penetrate and coat the already tightly aggregated primary carbon black particles. There is an upper limit to the dispersion stability, and it is prone to re-flocculation in high electrolyte systems (such as viscose spinning solutions).

[0004] To further improve the dispersibility of carbon black and enable its application in different systems, many researchers have focused on styrene-maleic anhydride copolymer-based dispersants in recent years. This copolymer has attracted widespread attention due to its amphiphilic structure and ease of modification. However, commonly used styrene-maleic anhydride copolymer-based dispersants show poor performance when directly applied to disperse carbon black. While methods such as improving its hydrophilicity or copolymerizing it with other components like acrylic acid can effectively improve its performance, problems remain regarding improving carbon black dispersibility and its application in viscose fibers, including a wide particle size distribution, large D50 particle size (typically >200 nm), and poor compatibility with viscose spinning solutions.

[0005] Therefore, there is an urgent need to find a new strategy that can solve the problem of carbon black dispersion at its source. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and a method for preparing highly dispersible carbon black using this dispersant. The dispersant prepared by the present invention exhibits excellent hydrophilicity and dispersion stability, making it suitable for strongly alkaline and high-electrolyte environments. The present invention fundamentally alters the surface physicochemical properties of carbon black by performing in-situ surface modification during the initial stage of carbon black formation—the "water-cooled cradle period"—thus preparing nano-carbon black with excellent self-dispersibility and stability in challenging application systems.

[0007] To achieve the above objectives, the present invention first provides a sulfonated styrene-maleic anhydride-acrylic acid grafted polyethylene glycol monomethyl ether dispersant. The dispersant is prepared by grafting a sulfonated styrene-maleic anhydride-acrylic acid copolymer with polyethylene glycol monomethyl ether. The structures of the sulfonated styrene-maleic anhydride-acrylic acid copolymer and the dispersant are shown in Formulas I and II, respectively: Formula I, Formula II, Where x:y:z is 1~2:1~2:0.1~1, 20≤x≤40, 20≤y≤40, 10≤z≤30; x, y and z are all integers, and 10≤n≤50.

[0008] In one embodiment of the present invention, the polyethylene glycol monomethyl ether accounts for 50-200 wt% of the mass of the sulfonated styrene-maleic anhydride-acrylic acid copolymer.

[0009] This invention also provides a method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant, comprising the following steps: (1) Under nitrogen protection, styrene, maleic anhydride, acrylic acid and solvent are mixed, and RAFT chain transfer agent and initiator are added to carry out copolymerization reaction to obtain copolymer mixed solution; (2) Add a poor solvent to the copolymer mixture obtained in step (1). After the reaction, the copolymer product precipitates out. After filtration, washing, and drying, styrene-maleic anhydride-acrylic acid copolymer (SMAA) is obtained. (3) After mixing and stirring concentrated sulfuric acid and phosphorus pentoxide, add the styrene-maleic anhydride-acrylic acid copolymer obtained in step (2) to react. After the reaction is completed, add the mixture to deionized water for precipitation and filtration. Dry the product to obtain sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (4) Dissolve the SSMAA polymer obtained in step (3) in a solvent, add polyethylene glycol monomethyl ether to react, and after the reaction is completed, separate the solvent and the product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) polymer dispersant.

[0010] In one embodiment of the present invention, the solvent in step (1) is one or more of dioxane, toluene, N,N dimethylformamide, and butyl acetate, and the added mass of the solvent is 200-500 wt% of the total mass of styrene, maleic anhydride and acrylic acid.

[0011] In one embodiment of the present invention, in step (1), the molar ratio of styrene to maleic anhydride is 1~10:1~10, and the molar ratio of styrene to acrylic acid is 1~10:0.1~5, preferably 5~10:1~3.

[0012] In one embodiment of the present invention, in step (1), the RAFT chain transfer agent is one or more of 1-phenylethyl dithiophenylacetic acid (PEPDA), 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid (DDMAT), and dithiobenzoyl disulfide compound (BTBD), and the added mass of the RAFT chain transfer agent is 0.1-5 wt% of the total mass of styrene, maleic anhydride and acrylic acid.

[0013] In one embodiment of the present invention, in step (1), the initiator is azobisisobutyronitrile (AIBN) and / or benzoyl peroxide (BPO), and the added mass of the initiator is 0.1 to 5% of the total mass of styrene, maleic anhydride and acrylic acid, preferably 0.2 to 1%.

[0014] In one embodiment of the present invention, in step (1), the temperature of the copolymerization reaction is 60~90℃, preferably 60~80℃, and mechanical stirring is performed during the copolymerization reaction. The mechanical stirring reaction time is 5-10 h, and the stirring speed is 200-600 rpm.

[0015] In one embodiment of the present invention, in step (2), the undesirable solvent is one or more of methanol, ethanol, n-octane, and n-heptane, and the undesirable solvent is 100 to 500 wt% of the solvent mass in step (1).

[0016] In one embodiment of the present invention, in step (2), the drying is performed in an oven at 30~60°C.

[0017] In one embodiment of the present invention, in step (3), the concentration of the concentrated sulfuric acid is 70-98%, the amount of concentrated sulfuric acid added is 1-10 times the mass of SMAA, preferably 2-8 times, the amount of phosphorus pentoxide added is 0.1-10 wt% of the mass of concentrated sulfuric acid, the reaction temperature is 30-60℃, preferably 40-50℃, and the reaction time is 0.5-2h, preferably 1h.

[0018] In one embodiment of the present invention, in step (3), the mass of the added deionized water is 100-500 wt% of the mass of concentrated sulfuric acid.

[0019] In one embodiment of the present invention, in step (4), the solvent is one or more of dioxane, toluene, N,N dimethylformamide, and butyl acetate, and the mass of the solvent added is 100-500 wt% of the mass of SSMAA.

[0020] In one embodiment of the present invention, in step (4), the degree of polymerization of the polyethylene glycol monomethyl ether is 10-50, the amount added accounts for 50-200 wt% of the mass of the sulfonated styrene-maleic anhydride-acrylic acid copolymer, and the reaction is carried out at 100-130℃ for 2-6 h.

[0021] In one embodiment of the present invention, after the dispersant is prepared, it is dispersed in a 5-20% dilute alkaline solution, wherein the solid content after dispersion is 40%-50% and the pH value is 9-11, and the dilute alkaline solution is a 5%-20% NaOH and / or KOH solution.

[0022] The present invention also provides an application of the above-mentioned sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant in the preparation of highly dispersible carbon black.

[0023] This invention also provides a method for preparing in-situ coated carbon black, comprising the following steps: (1) First, the air and coal tar are preheated. The air is heated to 800~900 ℃ by the air heater and sent into the reactor. Then the coal tar is preheated to 250~350 ℃ and sent into the reactor. The air and coal tar are used as raw materials for the reaction. (2) Natural gas and heated air are introduced into the reactor for combustion to generate a high-temperature combustion gas flow at a temperature of 1500~1800 ℃. Then, coal tar is introduced into the reactor and rapidly decomposed to generate carbon black and flue gas under high temperature conditions. The ratio of air to coal tar is 0.1~1:1; the ratio of natural gas to air is 1:10~20. (3) Cooling water is introduced into the reactor to rapidly lower its temperature and terminate the reaction; (4) When the temperature of the reactor drops to 200 °C, the mixture of dispersant and dilute alkali solution is introduced into the reactor at a mass ratio of 0.3~0.4:1 to coal tar, so that the temperature drops rapidly and the superdispersant coats the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by bag filter and granulated by dry granulation to obtain carbon black granules. (5) Add the prepared carbon black particles to deionized water, the carbon black slurry concentration is 20%, ultrasonic cavitation is performed for 20 min at a power of 80w, and a self-dispersing carbon black solution is obtained.

[0024] The present invention also provides a self-dispersing carbon black particle or self-dispersing carbon black solution prepared according to the above preparation method.

[0025] The present invention also discloses the use of the above-mentioned self-dispersing carbon black particles or self-dispersing carbon black solution in the textile field.

[0026] Beneficial effects: (1) The present invention synthesizes styrene-maleic anhydride-acrylic acid copolymer by RAFT polymerization. By sulfonating the styrene-maleic anhydride-acrylic acid copolymer and grafting the sulfonated styrene-maleic anhydride-acrylic acid copolymer with polyethylene glycol monomethyl ether, a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant is successfully synthesized. The dispersant prepared by the present invention has good dispersibility and dispersion stability and can be well applied in complex application environments with high electrolyte and strong alkalinity (such as viscose spinning solution).

[0027] (2) The present invention adds the prepared dispersant during the water cooling stage of carbon black formation, and successfully prepares carbon black with good dispersibility. The carbon black slurry prepared by the present invention can achieve an ultrafine particle size of D99 ≤ 500 nm with only gentle stirring and short-time grinding, which is far superior to the traditional process.

[0028] (3) This invention breaks away from the conventional thinking of "post-processing" and fundamentally changes the surface physicochemical properties of carbon black by performing in-situ surface modification in the initial stage of carbon black formation—the "water-cooled cradle period"—to prepare nano-carbon black with excellent self-dispersibility and stability in high-difficulty application systems. Furthermore, the preparation process saves grinding energy and equipment wear. Hard agglomeration is prevented from the source, and the dispersant coating layer on the surface of the carbon black particles is more complete and robust. Attached Figure Description

[0029] Figure 1 Optical micrographs of the dispersion of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer modified carbon black (a-b) prepared for Examples 1 and 11, styrene-maleic anhydride-acrylic acid copolymer modified carbon black (c) prepared for Comparative Example 1, and commercially available NNO modified carbon black for Comparative Example 3 in viscose spinning solution. Figure 2 The structural properties of the styrene-maleic anhydride-acrylic acid copolymer, sulfonated styrene-maleic anhydride-acrylic acid copolymer, and sulfonated styrene-maleic anhydride-acrylic acid grafted polyethylene glycol monomethyl ether dispersant in Example 1 are as follows: (a) 1 (b) 1H NMR spectrum; (c) Infrared spectrum; Figure 3 SEM images and EDS elemental analysis diagrams of sulfonated styrene-maleic anhydride-acrylic acid dispersants at different sulfonation temperatures in Examples 1, 6, and 7 are shown: (a) 40 ℃; (b) 50 ℃; (c) 60 ℃. Detailed Implementation

[0030] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0031] In the embodiments, comparative examples, and application examples of this invention, the raw materials used are all commercially available.

[0032] Test methods Particle size distribution was measured using a Nano-ZS90 laser particle size analyzer, and the particle size at room temperature was also measured.

[0033] GPC testing: The number-average molecular weight (Mn) of the polymer is 1000 to 50000 g / mol, and the molecular weight distribution index (PDI) is 1-10. The molecular weight is determined by gel permeation chromatography using THF as the mobile phase and calibrated with polystyrene standards.

[0034] Sulfonation degree test: The sulfur distribution of the polymer is detected by EDS energy dispersive spectroscopy, and then the sulfonation degree is calculated.

[0035] Compatibility test: The carbon black agglomeration of the viscose fiber membrane was observed using an optical microscope.

[0036] Example 1 A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm.

[0037] (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0038] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0039] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in 40 mL of dioxane solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100 °C for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene-maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) polymer dispersant.

[0040] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is 40% and the pH value is 10 to obtain dispersant SSMAA-g-MPEG-1.

[0041] Example 2 The difference between Example 2 and Example 1 is that the temperature of mechanical stirring in step (1) is 90°C.

[0042] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 90 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0043] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0044] (4) The product was dried at 50℃ to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) polymer dispersant.

[0045] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-2.

[0046] Example 3 The difference between Example 3 and Example 1 is that the temperature of mechanical stirring in step (1) is 60°C.

[0047] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 60 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0048] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0049] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Take 10 g of SSMAA polymer and dissolve it in a solvent. Add 5 g of polyethylene glycol monomethyl ether 1000 and react at 100℃ for 3 h. After the reaction is completed, separate the solvent and the product by rotary evaporation to finally obtain the sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether (SSMAA-g-MPEG) copolymer dispersant.

[0050] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-3.

[0051] Example 4 The difference between Example 4 and Example 1 is that the RAFT reagent added in step (1) is 0.8387 g of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid (DDMAT).

[0052] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.8387 g of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid (DDMAT) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0053] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually heat to 50 °C. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0054] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0055] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-4.

[0056] Example 5 The difference between Example 5 and Example 1 is that the RAFT reagent added in step (1) is 0.7049 g of benzoyl dithiocarbamate (BTBD).

[0057] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.7049 g of benzoyl dithiocarbamate (BTBD) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0058] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0059] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Take 10 g of sulfonated styrene-maleic anhydride-acrylic acid copolymer and dissolve it in a solvent. Add 5 g of polyethylene glycol monomethyl ether 1000 and react at 100℃ for 3 h. After the reaction is completed, separate the solvent and the product by rotary evaporation to finally obtain sulfonated styrene-maleic anhydride-acrylic acid copolymer grafted with polyethylene glycol monomethyl ether (SSMAA-g-MPEG) dispersant.

[0060] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-5.

[0061] Example 6 The difference between Example 6 and Example 1 is that the sulfonation reaction temperature in step (3) is 40°C.

[0062] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0063] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 40 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0064] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0065] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-6.

[0066] Example 7 The difference between Example 7 and Example 1 is that the sulfonation reaction temperature in step (3) is 60°C.

[0067] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0068] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 60 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0069] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0070] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-7.

[0071] Example 8 The difference between Example 8 and Example 1 is that the amount of initiator used in step (1) is 0.1886g.

[0072] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.1886 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0073] (3) Add 50g of concentrated sulfuric acid (98%) and 0.1g of phosphorus pentoxide to a three-necked flask, stir at 0 ℃ for 30 min, then add 10g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 ℃, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0074] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0075] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-8.

[0076] Example 9 The difference between Example 9 and Example 1 is that the amount of initiator used is 0.0472g.

[0077] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0472 g of initiator AIBN were added. The reaction was mechanically stirred at 70 °C for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0078] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0079] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0080] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-9.

[0081] Example 10 The difference between Example 10 and Example 1 is that the amount of acrylic acid added in step (1) is changed to 7.2g.

[0082] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 7.2 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 °C for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0083] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0084] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0085] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is 40% and the pH value is 10 to obtain dispersant SSMAA-g-MPEG-10.

[0086] Example 11 The difference between Example 11 and Example 1 is that the amount of RAFT reagent added in step (1) is changed to 0.0224 g.

[0087] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.0224 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0088] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0089] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0090] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-11.

[0091] Example 12 The difference between Example 12 and Example 1 is that the amount of concentrated sulfuric acid added in step (3) is changed to 10g.

[0092] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0093] (3) Add 10 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0094] (4) The product was dried at 50 °C to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 5 g of polyethylene glycol monomethyl ether 1000, react at 100℃ for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0095] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkali solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-12.

[0096] Example 13 The difference between Example 13 and Example 1 is that the amount of polyethylene glycol monomethyl ether 1000 added in step (5) is changed to 15g.

[0097] A method for preparing a sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant and its application in self-dispersing carbon black includes the following steps: (1) Under nitrogen protection, 40 mL of dioxane solvent, 10.4 g of styrene, 9.8 g of maleic anhydride, and 2.16 g of acrylic acid were added to a three-necked flask. The mixture was stirred for 30 min, and then 0.5934 g of 1-phenylethyl dithiophenylacetic acid ester (PEPDA) and 0.0943 g of initiator AIBN were added. The reaction was mechanically stirred at 70 ℃ for 6 h. The stirring speed was 300 rpm. (2) Add 100 mL of ethanol to the copolymer mixture solution after reaction, precipitate the copolymer product, filter and wash, and dry in a 60 ℃ oven to prepare styrene-maleic anhydride-acrylic acid copolymer (SMAA).

[0098] (3) Add 50 g of concentrated sulfuric acid (98%) and 0.1 g of phosphorus pentoxide to a three-necked flask, stir at 0 °C for 30 min, then add 10 g of styrene-maleic anhydride-acrylic acid copolymer and gradually raise the temperature to 50 °C, react for 1 h. After the reaction is complete, add the mixture to 500 mL of deionized water for precipitation and filtration.

[0099] (4) The product was dried at 50℃ to prepare sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (5) Dissolve 10 g of SSMAA polymer in a solvent, add 15 g of polyethylene glycol monomethyl ether 1000, react at 100 °C for 3 h, and after the reaction is complete, separate the solvent and product by rotary evaporation to finally obtain sulfonated styrene-maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) dispersant.

[0100] (6) Mix 5 g of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) with 12.5 g of 10% NaOH dilute alkaline solution and stir until uniform. The solid content is about 40% and the pH value is about 10, thus obtaining dispersant SSMAA-g-MPEG-13.

[0101] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the styrene-maleic anhydride-acrylic acid copolymer (SMAA) prepared in step (2) was directly mixed with 10% NaOH dilute alkaline solution and stirred evenly to obtain a dispersant.

[0102] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the sulfonated styrene-maleic anhydride-acrylic acid copolymer obtained in step (4) was directly mixed with 10% NaOH dilute alkaline solution to prepare the dispersant sulfonated styrene-maleic anhydride-acrylic acid copolymer SSMAA.

[0103] Comparative Example 3 The dispersant is a commercially available NNO dispersant.

[0104] Comparative Example 4 The dispersant is a commercially available styrene-maleic anhydride dispersant.

[0105] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the molar ratio of styrene, maleic anhydride and acrylic acid was changed to 1:1:5.

[0106] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the sulfonation treatment in steps (4) and (5) is omitted, and the styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether (SMAA-g-MPEG) copolymer after grafting polyether is directly dissolved in dilute alkaline solution to obtain the dispersant SMAA-g-MPEG.

[0107] Figure 2 The materials used in Example 1 are styrene-maleic anhydride-acrylic acid copolymer, sulfonated styrene-maleic anhydride-acrylic acid copolymer, and sulfonated styrene-maleic anhydride-acrylic acid grafted polyethylene glycol monomethyl ether dispersant. 1 In the ¹H NMR and IR spectra of styrene-maleic anhydride-acrylic acid copolymer (SMAA), the multiplet at δ = 6.5–7.6 ppm corresponds to aromatic protons on the benzene ring of the styrene side group. The signal at δ = 3.47 ppm is attributed to the methylene proton of the maleic anhydride unit in the copolymer. The signals at δ = 1.27 and 2.21 ppm correspond to methylene (-CH₂-) and methylene (-CH-) protons on the main chain, respectively. Furthermore, the broad peak at δ = 12.3 ppm originates from the carboxyl hydrogen of the acrylic acid unit. In the spectrum of sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA), the characteristic peak of the benzene ring at δ = 6.5–7.6 ppm becomes broader and blunter. This is because the introduction of strongly electron-withdrawing sulfonic acid groups alters the electronic environment of the benzene ring. Simultaneously, the strongly polar groups enhance the interactions between molecular chains, leading to signal overlap. The signals at δ = 12.3, 3.47, 1.27, and 2.21 ppm also became smoother. In the spectrum of the copolymer grafted with polyethylene glycol monomethyl ether (SSMAA-g-MPEG), a very strong peak appeared at δ = 3.5–3.7 ppm. This peak is attributed to the numerous repeating methylene (-CH2CH2O-) protons on the polyethylene glycol monomethyl ether backbone. Simultaneously, a new broad peak appeared at δ = 4.1–4.3 ppm. This peak corresponds to the methylene protons (-CH2-OC=O-) near the ester group. This result strongly demonstrates that polyethylene glycol monomethyl ether has been successfully grafted onto the polymer backbone via chemical bonds.

[0108] The evolution of functional groups in the copolymer was detected by FT-IR spectroscopy. In the spectrum of styrene-maleic anhydride-acrylic acid copolymer (SMAA), the 1850 cm⁻¹... -1 and 1780 cm -1 The characteristic double peak at [location] is attributed to the symmetric and asymmetric stretching vibrations of the carbonyl group in the acid anhydride. The skeletal vibrations of the benzene ring appear at 1600 cm⁻¹. -1 and 1493 cm -1 After sulfonation, at 1127 cm -1 and 1034 cm -1 The new absorption band at this point corresponds to the S=O stretching vibration, confirming the successful introduction of the sulfonic acid group into the benzene ring. Simultaneously, the intensity of the anhydride peak significantly decreases, indicating partial hydrolysis. After grafting polyethylene glycol monomethyl ether, the spectrum of sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether shows a value at 1077 cm⁻¹. -1 There is a major peak at 1722 cm⁻¹, corresponding to the COC stretching vibration of the polyether chain. Additionally, there is a peak at 1722 cm⁻¹. -1 A new peak appears at 2859 cm⁻¹ (ester C=O). -1 The enhanced peak at this point is due to the CH stretching vibration of the methylene group in the polyethylene glycol monomethyl ether chain, which verifies that polyethylene glycol monomethyl ether was successfully chemically grafted through esterification.

[0109] Application examples A method for preparing self-dispersing carbon black includes the following steps (the carbon black is prepared using a conventional furnace method): (1) First, the air and coal tar are preheated. The air is heated to 850°C by the air heater and sent into the reactor. Then the coal tar is preheated to 300°C and sent into the reactor. The air and coal tar are used as raw materials for the reaction. (2) Natural gas and heated air are introduced into the reactor for combustion to generate a high-temperature combustion gas flow at a temperature of 1600 ℃. Then, coal tar is introduced into the reactor and rapidly decomposed to generate carbon black and flue gas under high temperature conditions. The ratio of air to coal tar is 0.5:1, and the ratio of natural gas to air is 1:15.

[0110] (3) Pass cooling water (room temperature water) into the reactor to rapidly lower its temperature and terminate the reaction; (4) When the temperature of the reactor drops to 200 °C, the dispersant solution of the example or comparative example is introduced into the reactor at a mass ratio of 0.33:1 to coal tar, so that the temperature drops rapidly and the superdispersant coats the carbon black surface. The cooled carbon black and flue gas are separated and collected by bag filter and granulated by dry granulation to obtain carbon black granules. (5) The carbon black particles were added to deionized water to obtain a carbon black slurry with a concentration of 20%. The slurry was ultrasonically cavitated for 20 min at a power of 80W to obtain a self-dispersing carbon black solution.

[0111] (6) The self-dispersing carbon black solution and viscose spinning solution (9 wt%) were mixed evenly at a ratio of 1:100. The mixture was then coated using a coater and immersed in a coagulation bath to form a viscose fiber membrane. The coagulation bath consisted of sulfuric acid, zinc sulfate, and sodium sulfate. The concentrations of sulfuric acid, zinc sulfate, and sodium sulfate were 10 wt%, 12 wt%, and 2 wt%, respectively. The solution temperature was 50℃.

[0112] Table 1. Properties of dispersants and carbon black prepared in the examples and comparative examples.

[0113] Note: √ indicates that the carbon black is evenly dispersed in the viscose spinning solution without obvious agglomeration; Δ indicates that there is a small amount of carbon black agglomeration; × indicates that there is obvious carbon black agglomeration.

[0114] The test results of Examples 1-3 show that the reaction temperature has a significant impact on the polymer molecular weight. Excessively high temperatures accelerate the polymerization rate but decrease the degree of polymerization. Conversely, excessively low temperatures result in a slow reaction and difficulty in increasing the degree of polymerization. Experiments revealed that the optimal reaction temperature for the polymerization of maleic anhydride, styrene, and acrylic acid is below 90°C, and more preferably 60-80°C. Examples 1, 4, and 5 demonstrate that different RAFT reagents have a significant impact on the polydispersity index. A comparison of Examples 1, 6, and 7 shows that as the sulfonation temperature increases, the degree of sulfonation gradually increases, but the yield gradually decreases. The SEM images and EDS elemental analysis diagrams of the sulfonated styrene-maleic anhydride-acrylic acid dispersants in Examples 1, 6, and 7 are shown below. Figure 3As shown, to balance the yield and degree of sulfonation, the sulfonation reaction temperature is preferably 40-60℃. A comparison of Examples 1, 8, and 9 shows that the amount of initiator has a significant impact on the molecular weight; excessive initiator dosage intensifies the free radical polymerization rate. Reducing the initiator dosage slows the reaction and lowers the molecular weight; the preferred initiator dosage is 0.2-1% of the total amount of the three monomers. Examples 10 and Comparative Example 5 show that the copolymer molecular weight decreases significantly with increasing acrylic acid content. This is due to the enhanced chain transfer effect of acrylic acid and the reduced chain growth efficiency caused by the disruption of alternating structures. Example 11 shows that when the RAFT reagent is reduced, the polydispersity index of the copolymer increases, leading to a wider distribution. Example 12 shows that when the amount of concentrated sulfuric acid is reduced, the degree of sulfonation decreases, and the carbon black dispersion effect is slightly worse. Example 13 shows that when the amount of grafted polyethylene glycol monomethyl ether 1000 is excessive, the amount of polyether in the grafted copolymer is large. Bridging occurs during carbon black dispersion, leading to increased particle size. Compared with comparative examples 1-3 and 6, the unsulfonated dispersant exhibits poor hydrophilicity and suboptimal self-dispersibility. Commercially available dispersants also show poor compatibility with viscose spinning solutions, making them difficult to disperse uniformly in strongly alkaline spinning solutions.

[0115] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant, characterized in that, The dispersant is prepared by grafting sulfonated styrene-maleic anhydride-acrylic acid copolymer with polyethylene glycol monomethyl ether. The structures of the sulfonated styrene-maleic anhydride-acrylic acid copolymer and the dispersant are shown in Formulas I and II, respectively. Formula I, Formula II, Where x:y:z is 1~2:1~2:0.1~1, 20≤x≤40, 20≤y≤40, 10≤z≤30; x, y and z are all integers, and 10≤n≤50.

2. The sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant according to claim 1, characterized in that, The polyethylene glycol monomethyl ether accounts for 50-200 wt% of the sulfonated styrene-maleic anhydride-acrylic acid copolymer.

3. A method for preparing the sulfonated styrene-maleic anhydride-acrylic acid-grafted polyethylene glycol monomethyl ether dispersant according to claim 1 or 2, characterized in that, Includes the following steps: (1) Under nitrogen protection, styrene, maleic anhydride, acrylic acid and solvent are mixed, and RAFT chain transfer agent and initiator are added to carry out copolymerization reaction to obtain copolymer mixed solution; (2) Add a poor solvent to the copolymer mixture obtained in step (1). After the reaction, the copolymer product precipitates out. After filtration, washing, and drying, styrene-maleic anhydride-acrylic acid copolymer (SMAA) is obtained. (3) After mixing and stirring concentrated sulfuric acid and phosphorus pentoxide, add the styrene-maleic anhydride-acrylic acid copolymer obtained in step (2) to react. After the reaction is completed, add the mixture to deionized water for precipitation and filtration. Dry the product to obtain sulfonated styrene-maleic anhydride-acrylic acid copolymer (SSMAA). (4) Dissolve the SSMAA polymer obtained in step (3) in a solvent, add polyethylene glycol monomethyl ether to react, and after the reaction is completed, separate the solvent and the product by rotary evaporation to finally obtain sulfonated styrene maleic anhydride acrylic acid grafted polyethylene glycol monomethyl ether copolymer (SSMAA-g-MPEG) polymer dispersant.

4. The preparation method according to claim 3, characterized in that, The solvent in step (1) is one or more of dioxane, toluene, N,N dimethylformamide, and butyl acetate. The added mass of the solvent is 200-500 wt% of the total mass of styrene, maleic anhydride, and acrylic acid. The molar ratio of styrene to maleic anhydride is 1-10:1-10, and the molar ratio of styrene to acrylic acid is 1-10:0.1-5.

5. The preparation method according to claim 3, characterized in that, In step (1), the RAFT chain transfer agent is one or more of 1-phenylethyl dithiophenylacetic acid (PEPDA), 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid (DDMAT), and dithiobenzoyl disulfide (BTBD). The added mass of the RAFT chain transfer agent is 0.1-5 wt% of the total mass of styrene, maleic anhydride, and acrylic acid. The initiator is azobisisobutyronitrile (AIBN) and / or benzoyl peroxide (BPO). The added mass of the initiator is 0.1-5% of the total mass of styrene, maleic anhydride, and acrylic acid. The temperature of the copolymerization reaction is 60-90°C.

6. The preparation method according to claim 3, characterized in that, In step (2), the undesirable solvent is one or more of methanol, ethanol, n-octane, and n-heptane, and the undesirable solvent is 100-500 wt% of the solvent in step (1). The drying is carried out in an oven at 30-60°C.

7. The preparation method according to claim 3, characterized in that, In step (3), the concentration of the concentrated sulfuric acid is 70-98%, the amount of concentrated sulfuric acid added is 1-10 times the mass of SMAA, the amount of phosphorus pentoxide added is 0.1-10 wt% of the mass of concentrated sulfuric acid, the reaction temperature is 30-60℃, the reaction time is 0.5-2h, and the mass of deionized water added is 100-500 wt% of the mass of concentrated sulfuric acid.

8. The preparation method according to claim 3, characterized in that, The solvent mentioned in step (4) is one or more of dioxane, toluene, N,N dimethylformamide, and butyl acetate. The added mass of the solvent is 100-500 wt% of the mass of SSMAA. The dispersant is dispersed in a 5-20% dilute alkaline solution, wherein the solid content after dispersion is 40%-50%, the pH value is 9-11, and the dilute alkaline solution is a 5%-20% NaOH and / or KOH solution.

9. A method for preparing in-situ coated carbon black, characterized in that, Includes the following steps: (1) First, air preheating and coal tar preheating are carried out. The air is heated to 800~900 ℃ by an air heater and sent into the reactor. The coal tar is then preheated to 250-350 ℃ and then fed into the reactor, where air and coal tar are used as reaction raw materials. (2) Natural gas and heated air are introduced into the reactor for combustion to generate a high-temperature combustion gas flow at a temperature of 1500~1800 ℃. Then, coal tar is introduced into the reactor and rapidly decomposed to generate carbon black and flue gas under high temperature conditions. The ratio of air to coal tar is 0.1~1:1; the ratio of natural gas to air is 1:10~20. (3) Cooling water is introduced into the reactor to rapidly lower its temperature and terminate the reaction; (4) When the temperature of the reactor drops to 200 °C, the mixture of the dispersant and dilute alkali solution described in claim 1 or 2 is introduced into the reactor at a mass ratio of 0.3 to 0.4:1 with coal tar, so that the temperature drops rapidly and the super-dispersant coats the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter and granulated by dry granulation to obtain carbon black granules. (5) Add the prepared carbon black particles to deionized water, the carbon black slurry concentration is 20%, ultrasonic cavitation is performed for 20 min at a power of 80w, and a self-dispersing carbon black solution is obtained.

10. The use of the self-dispersing carbon black particles or self-dispersing carbon black solution prepared by the preparation method according to claim 9 in the textile field.

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