A star polymer, its preparation method and application, a dispersant and a dispersion method

Abstract

The present invention provides a star polymer, a preparation method thereof and an application thereof. The preparation method of the star polymer includes: providing a first compound having a plurality of branched chains; subjecting the active groups on at least four branched chains of the first compound to an acylation reaction with at least an acylating agent a to obtain a second compound a; subjecting the active groups on at least four branched chains of the first compound to an acylation reaction with at least an acylating agent b to obtain a second compound b; using the second compound a as an initiator to initiate a polymerization reaction of the second compound b with a compound containing an alkenyl group to obtain a star polymer. The star polymer prepared by the present invention has better dispersibility and stability compared with traditional surfactants, and has good application prospects in fields such as conductive carbon black pulping. The present invention also provides a dispersant including the above star polymer and a dispersion method using the above star polymer.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a star polymer, a preparation method and application thereof, a dispersant and a dispersion method. Background Art

[0002] Carbon black belongs to amorphous carbon and is obtained by incomplete combustion of carbon-containing substances such as petroleum through thermal decomposition. The main body of carbon black is carbon element, doped with trace amounts of hydrogen, oxygen, sulfur, ash and tar, presenting pure black fine powder particles, with small particle size and large specific surface area, and is insoluble in water, acids and alkalis.

[0003] There is a strong aggregation between carbon black particles, and it is easy to flocculate during the preparation and use of carbon black. The flocculation of carbon black easily causes damage to the grinding machine, uneven dispersion of pigments, and also affects the blackness and covering power of carbon black, and even increases the viscosity, resulting in an increase in the system resistance. This characteristic of carbon black is mainly related to the "wetting energy" being too high due to the large specific surface area of carbon black particles. Therefore, dispersants are usually added during the preparation and use of carbon black to inhibit the occurrence of the above situations. Some traditional surfactants have low molecular weight, poor dispersion performance, or weak stability, and are not suitable for dispersing substances with high requirements for dispersion performance such as carbon black. In addition, the action mechanism of traditional linear dispersants is to change the ratio of hydrophilic and hydrophobic groups in the system, increasing the content of free water in three-dimensional space. However, after long-term standing, the free water will precipitate, the water precipitation rate becomes larger, the movable range of carbon black particles becomes larger, and the sedimentation phenomenon is serious. Therefore, finding a dispersant with good dispersion effect is of great significance for the application of carbon black.

[0004] Based on this, the present application patent synthesizes a variety of high-molecular-weight nonlinear star dispersants, in order to increase the electrostatic repulsion between particles through the steric hindrance and molecular weight of the star dispersant itself in three-dimensional space, so that the carbon black particles in the system can exist stably. Summary of the Invention

[0005] To solve the above-mentioned part or all of the problems, the present invention provides the following technical solutions.

[0006] One of the purposes of the present invention is to provide a preparation method of a star polymer, including: providing a first compound having a plurality of branched chains; subjecting the active groups on at least four branched chains of the first compound to an acylation reaction with at least an acylating agent a to obtain a second compound a; subjecting the active groups on at least four branched chains of the first compound to an acylation reaction with at least an acylating agent b to obtain a second compound b; using the second compound a as an initiator to initiate a polymerization reaction between the second compound b and a compound containing an alkenyl group to obtain a star polymer.

[0007] In some embodiments, the first compound includes, but is not limited to, one or more of mannose, pyromellitic acid, glucose, galactose, sorbose, and cyclodextrin having 6 to 8 units.

[0008] In some embodiments, the acylating agent contains a double-bond-free acylating agent, and the double-bond-free acylating agent includes, but is not limited to, one or more of chloroacetyl chloride, 2-bromo-2-methylpropionyl bromide, p-chlorobenzoyl chloride, and p-chlorophenyl chloroformate.

[0009] In some embodiments, the acylating agent b includes a double-bond-containing acylating agent, and the double-bond-containing acylating agent includes, but is not limited to, one or more of allyl bromide, acryloyl chloride, acryloyl bromide, and 2-bromoethyl methacrylate.

[0010] In some embodiments, the compound containing an alkenyl group includes, but is not limited to, one or more of allyl polyoxyethylene ether, ethyl acrylate, sodium vinylphenylmethanesulfonate, sodium allylsulfonate, sodium methallylsulfonate, vinyl acetate, sodium styrenesulfonate, and methyl methacrylate.

[0011] In some embodiments, in the acylation reaction, the mass ratio of the first compound to the acylating agent a and the acylating agent b is 1:1 to 1:23.6.

[0012] In some embodiments, in the polymerization reaction, the mass ratio of the second compound b to the compound containing an alkenyl group is 1:2.2 to 1:50.4. When the content of the second compound b in the polymerization reaction is lower than this range, the compound containing an alkenyl group mainly exists in the system, resulting in poor system stability; when the content of the second compound b is higher than this range, the molecular weight distribution range is too wide, and polymer molecules of different sizes in the system will crosslink and polymerize with each other, resulting in too high system viscosity.

[0013] In some embodiments, specifically, the acylating agent a and the acylating agent b are respectively added in batches to the solvent containing the first compound to form a mixed reaction solution, and the addition time of the acylating agent a and the acylating agent b is 30 to 100 min. Adding the acylating agent a and the acylating agent b in batches can control the heat release. If added too fast and the addition time is shorter than this range, the reaction raw materials will be instantly solidified, affecting the progress of the reaction; if the reaction time exceeds this range, the reaction time is too long, the time cost is high, and the production efficiency is low.

[0014] In some embodiments, the solvent in the acylation reaction includes one or more of tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0015] In some embodiments, the temperature of the acylation reaction can be, for example, -2 to 25 °C.

[0016] In some embodiments, the time of the acylation reaction can be, for example, 3 to 48 h.

[0017] In some embodiments, the temperature of the polymerization reaction can be, for example, 60 °C to 100 °C. When the polymerization reaction temperature is lower than this range, the reaction rate is too slow and the time cost is large; when the temperature is higher than this range, the reaction is too fast, the graft molecular weight of the polymer is too high and crosslinking occurs, generating gel.

[0018] In some embodiments, the time of the polymerization reaction is 4 to 24 h.

[0019] Another object of the present invention is to provide a star polymer prepared by the above preparation method; preferably, the weight-average molecular weight of the star polymer is greater than 100 kDa, more preferably 100 kDa - 700 kDa.

[0020] Another object of the present invention is to provide the application of the star polymer in dispersing carbon black particles.

[0021] Another object of the present invention is to provide a dispersant comprising the star polymer in the above technical solution.

[0022] Another object of the present invention is to provide a dispersion method, the dispersion method comprising: uniformly dispersing carbon black particles in a dispersant in the presence of a dispersant; the dispersant comprising the star polymer in the above technical solution.

[0023] In some embodiments, the dispersion method specifically comprises: uniformly dispersing carbon black particles in a dispersant in the presence of a dispersant, and stirring at a rotation speed of 500 - 800 rpm for 3 - 10 min.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] (1) The present invention acylates a compound (the first compound) having a multi-branched main structural unit with an acylating agent, and uses the second compound a obtained from the acylation reaction as an initiator to initiate the polymerization reaction of the second compound b with a similar structure to obtain a high molecular weight non-linear star polymer; this star polymer can increase the electrostatic repulsion between particles through its own steric hindrance and molecular weight, so when it is applied to the dispersion of carbon black particles, the carbon black particles in the system can exist stably, and it has better dispersibility and stability compared with traditional low molecular weight surfactants, and has good application prospects in fields such as conductive carbon black pulping.

[0026] (2) The preparation method adopted by the present invention conducts the acylation reaction and the polymerization reaction at a lower temperature, and the synthesis steps are simple and easy to operate, and have economic and large-scale application prospects. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 is a schematic reaction flow chart for preparing star polymers in an embodiment of the present invention;

[0029] Figure 2 is the gel permeation chromatography analysis distribution diagram of Mannose-PSAS prepared in an embodiment of the present invention 1 . Detailed Embodiments

[0030] The following will describe in detail the technical solutions of the present invention in combination with specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be construed as restrictive, but only as the basis of the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in any appropriate detailed embodiment in different ways.

[0031] In view of the deficiencies of the prior art, the inventors of this case have conducted experimental research and have been able to propose the technical solutions of the present invention. It is mainly aimed at the defects of existing low-molecular-weight dispersants (such as CTAB) used in carbon black pulping experiments. The star polymers provided by the present invention can disperse carbon black in water to form a uniform and stable slurry, and all performance indicators are better than commercial CTAB.

[0032] The following will make a detailed description of the specific embodiments of the present invention in combination with the drawings. Unless otherwise specified, the experimental instruments and reagents used in the embodiments can be purchased through conventional channels. For the steps or conditions with special instructions, they can be carried out according to the conventional experimental steps or conditions described in the literature in the field.

[0033] Figure 1 is the preparation flow chart of the star polymer provided by the present invention, Figure 1 in which St represents the first compound, and the first compound has at least four or more Y functional groups, where Y represents -OH / -NH 2 ;

[0034] X 1 -R 1 -X 2 represents the acylating agent a, where R 1Represents a functional group containing an acyl group, X 1 and X 2 represent halogen groups, and the halogen groups include Br and Cl; the Y functional groups on at least four branches of the first compound St undergo an acylation reaction with the acylating agent a to form a second compound a with a star structure, and the second compound a is denoted as X 2 -R 1 -St;

[0035] represents the acylating agent b, where R 2 represents a C-C or aromatic group containing a halogen; the Y functional groups on at least four branches of the first compound St undergo an acylation reaction with the acylating agent b to form a second compound b with a star structure and similar to the structure of the first compound a, and the second compound b is denoted as CH 2 =CH-R 2 -St;

[0036] CH 2 =CH-R’ represents a compound containing an alkenyl group, where R’ represents an aliphatic C-C or an aromatic benzene ring.

[0037] Example 1

[0038] (1) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 4.766 g of chloroethyl chloroformate was added dropwise, controlling the dropping time to be 30 min to form a mixed reaction solution. The acylation reaction was carried out at 25 °C for 2.5 h, and after filtration and drying, the second compound a was obtained, denoted as C1-Mannose;

[0039] (2) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of bromoethyl methacrylate was added dropwise, controlling the dropping time to be 30 min to form a mixed reaction solution. The acylation reaction was carried out at 25 °C for 2.5 h, and after filtration and drying, the second compound b was obtained, denoted as CH 2 =CH-Mannose;

[0040] (3) 0.1 g of Cl-Mannose was added to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allyl sulfonate (SAS), and continuous stirring was accompanied. The polymerization reaction was carried out at 95 °C for 2.5 h. After the reaction ended, it was naturally cooled to room temperature to obtain a star polymer, denoted as Mannose-PSAS 1 . The reaction equation is as follows:

[0041]

[0042] Example 2

[0043] (1) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 4.766 g of chloroethyl chloroformate while controlling the dropping time to be 30 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound a, denoted as Cl-Mannose;

[0044] (2) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 6.436 g of bromoethyl methacrylate while controlling the dropping time to be 30 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0045] (3) Add 0.1 g of Cl-Mannose to an aqueous solution of 1.5 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and stir continuously. Carry out a polymerization reaction at 95 °C for 2.5 h. After the reaction is completed, naturally cool to room temperature to obtain a star polymer, denoted as Mannose-PSAS 2 .

[0046] Example 3

[0047] (1) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 4.766 g of chloroethyl chloroformate while controlling the dropping time to be 30 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound a, denoted as Cl-Mannose;

[0048] (2) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 6.436 g of bromoethyl methacrylate while controlling the dropping time to be 30 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0049] (3) Add 0.1 g of Cl-Mannose to an aqueous solution of 2.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and stir continuously. Carry out a polymerization reaction at 95 °C for 2.5 h. After the reaction is completed, naturally cool to room temperature to obtain a star polymer, denoted as Mannose-PSA 3 .

[0050] Example 4

[0051] (1) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 4.766 g of chloroethyl chloroformate while controlling the dropping time to be 60 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound a, denoted as C1-Mannose;

[0052] (2) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 6.436 g of bromoethyl methacrylate while controlling the dropping time to be 60 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0053] (3) Add 0.1 g of Cl-Mannose to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and stir continuously. Carry out a polymerization reaction at 95 °C for 2.5 h. After the reaction is completed, naturally cool to room temperature to obtain a star-shaped polymer, denoted as Mannose-PSAS 4 .

[0054] Example 5

[0055] (1) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 4.766 g of chloroethyl chloroformate while controlling the dropping time to be 80 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound a, denoted as Cl-Mannose;

[0056] (2) Under an ice bath, dissolve 1.0 g of mannose in 9.0 g of tetrahydrofuran, and dropwise add 6.436 g of bromoethyl methacrylate while controlling the dropping time to be 80 min to form a mixed reaction solution. Carry out an acylation reaction at 25 °C for 2.5 h, filter and dry to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0057] (3) Add 0.1 g of Cl-Mannose to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and stir continuously. Carry out a polymerization reaction at 95 °C for 2.5 h. After the reaction is completed, naturally cool to room temperature to obtain a star-shaped polymer, denoted as Mannose-PSAS 5 .

[0058] Example 6

[0059] (1) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 4.766 g of chloroethyl chloroformate was added dropwise thereto, controlling the dropping time to be 90 min to form a mixed reaction solution, and the acylation reaction was carried out at 25 °C for 2.5 h. After filtration and drying, the second compound a, denoted as Cl-Mannose, was obtained;

[0060] (2) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of bromoethyl methacrylate was added dropwise thereto, controlling the dropping time to be 90 min to form a mixed reaction solution, and the acylation reaction was carried out at 25 °C for 2.5 h. After filtration and drying, the second compound b, denoted as CH 2 =CH-Mannose;

[0061] (3) 0.1 g of Cl-Mannose was added to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and continuous stirring was accompanied. The polymerization reaction was carried out at 95 °C for 2.5 h. After the reaction was completed, it was naturally cooled to room temperature to obtain a star polymer, denoted as Mannose-PSAS 6 .

[0062] Example 7

[0063] (1) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 4.766 g of chloroethyl chloroformate was added dropwise thereto, controlling the dropping time to be 60 min to form a mixed reaction solution, and the acylation reaction was carried out at 25 °C for 2.5 h. After filtration and drying, the second compound a, denoted as Cl-Mannose, was obtained;

[0064] (2) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of bromoethyl methacrylate was added dropwise thereto, controlling the dropping time to be 60 min to form a mixed reaction solution, and the acylation reaction was carried out at 25 °C for 2.5 h. After filtration and drying, the second compound b, denoted as CH 2 =CH-Mannose;

[0065] (3) 0.1 g of Cl-Mannose was added to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and continuous stirring was accompanied. The polymerization reaction was carried out at 65 °C for 2.5 h. After the reaction was completed, it was naturally cooled to room temperature to obtain a star polymer, denoted as Mannose-PSAS 7 .

[0066] Example 8

[0067] (1) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 4.766 g of chloroethyl chloroformate was added dropwise thereto while controlling the dropping time to 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, followed by filtration and drying to obtain a second compound a, denoted as Cl-Mannose;

[0068] (2) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of bromoethyl methacrylate was added dropwise thereto while controlling the dropping time to 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, followed by filtration and drying to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0069] (3) 0.1 g of Cl-Mannose was added to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allyl sulfonate (SAS), and the mixture was continuously stirred and subjected to a polymerization reaction at 75 °C for 2.5 h. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a star polymer, denoted as Mannose-PSAS 8 .

[0070] Example 9

[0071] (1) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 4.766 g of chloroethyl chloroformate was added dropwise thereto while controlling the dropping time to 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, followed by filtration and drying to obtain a second compound a, denoted as Cl-Mannose;

[0072] (2) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of bromoethyl methacrylate was added dropwise thereto while controlling the dropping time to 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, followed by filtration and drying to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0073] (3) 0.1 g of Cl-Mannose was added to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allyl sulfonate (SAS), and the mixture was continuously stirred and subjected to a polymerization reaction at 85 °C for 2.5 h. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a star polymer, denoted as Mannose-PSAS 9 .

[0074] Example 10

[0075] (1) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 7.67 g of 2-bromo-2-methylpropionyl bromide was added dropwise thereto while controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, and then filtered and dried to obtain a second compound a, denoted as C1-Mannose;

[0076] (2) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of 2-bromoethyl methacrylate was added dropwise thereto while controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, and then filtered and dried to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0077] (3) 0.1 g of Cl-Mannose was added to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and the mixture was continuously stirred and subjected to a polymerization reaction at 95 °C for 2.5 h. After the reaction was completed, the reaction mixture was naturally cooled to room temperature to obtain a star polymer, denoted as Mannose-PSAS 10 .

[0078] Example 11

[0079] (1) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 5.83 g of p-chlorobenzoyl chloride was added dropwise thereto while controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, and then filtered and dried to obtain a second compound a, denoted as C1-Mannose;

[0080] (2) Under an ice bath, 1.0 g of mannose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of 2-bromoethyl methacrylate was added dropwise thereto while controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, and then filtered and dried to obtain a second compound b, denoted as CH 2 =CH-Mannose;

[0081] (3) 0.1 g of Cl-Mannose was added to an aqueous solution of 1.0 g of CH 2 =CH-Mannose and 10.2 g of sodium allylsulfonate (SAS), and the mixture was continuously stirred and subjected to a polymerization reaction at 95 °C for 2.5 h. After the reaction was completed, the reaction mixture was naturally cooled to room temperature to obtain a star polymer, denoted as Mannose-PSAS 11 .

[0082] Example 12

[0083] (1) Under an ice bath, 1.0 g of galactose was dissolved in 9.0 g of tetrahydrofuran, and 6.37 g of p-chlorophenyl chloroformate was added dropwise thereto, controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, and then filtered and dried to obtain a second compound a, denoted as C1-Galactose;

[0084] (2) Under an ice bath, 1.0 g of galactose was dissolved in 9.0 g of tetrahydrofuran, and 6.436 g of 2-bromoethyl methacrylate was added dropwise thereto, controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 2.5 h, and then filtered and dried to obtain a second compound b, denoted as CH 2 =CH-Galactose;

[0085] (3) 0.1 g of Cl-Galactose was added to an aqueous solution of 1.0 g of CH 2 =CH-Galactose and 10.2 g of sodium allylsulfonate (SAS), and the mixture was continuously stirred. A polymerization reaction was carried out at 95 °C for 2.5 h. After the reaction was completed, it was naturally cooled to room temperature to obtain a star polymer, denoted as Galactose-PSAS 1 .

[0086] Example 13

[0087] (1) Under an ice bath, 1.0 g of pyromellitic acid (PMA) was dissolved in 9.0 g of tetrahydrofuran, and 1.0 g of chloroethyl chloroformate was added dropwise thereto, controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 6.5 h, and then filtered and dried to obtain a second compound a, denoted as Cl-PMA;

[0088] (2) Under an ice bath, 1.0 g of mannose (PMA) was dissolved in 9.0 g of tetrahydrofuran, and 1.0 g of 2-bromoethyl methacrylate was added dropwise thereto, controlling the dropping time to be 60 min to form a mixed reaction solution, which was subjected to an acylation reaction at 25 °C for 6.5 h, and then filtered and dried to obtain a second compound b, denoted as CH 2 =CH-PMA;

[0089] (3) 0.1 g of Cl-PMA was added to an aqueous solution of 2.0 g of CH 2 =CH-Mannose and 25.9 g of ethyl acrylate (EA), and the mixture was continuously stirred. A polymerization reaction was carried out at 95 °C for 2.5 h. After the reaction was completed, it was naturally cooled to room temperature to obtain a star polymer, denoted as PMA-EA-1. The reaction equation is as follows:

[0090]

[0091] Comparative Example 1

[0092] The difference between Comparative Example 1 and Example 1 is only that: in step (2), the mass ratio of the second compound b (i.e., mannose-based vinyl monomer) to SAS is controlled to be 1:2.2.

[0093] Comparative Example 2

[0094] The difference between Comparative Example 2 and Example 1 is only that: in step (2), the mass ratio of the second compound b (i.e., mannose-based vinyl monomer) to SAS is controlled to be 1:50.4.

[0095] The above two comparative examples mainly focus on the ratio of the second compound b to SAS in the polymer system. When there is too little of the second compound b in the polymer, the system mainly consists of SAS monomers. Since it is a linear small monomer, it does not meet the actual objectives of this application, ultimately resulting in poor system stability; when there is too much of the second compound b, the molecular weight distribution range is too wide, and polymer molecules of various sizes in the system will crosslink and polymerize with each other, resulting in too high viscosity of the system.

[0096] Comparative Example 3

[0097] The difference between Comparative Example 3 and Example 1 is only that: in step (1-2), the addition times of acylating agent a and acylating agent b are not controlled, and they can be directly poured in.

[0098] Comparative Example 4

[0099] The difference between Comparative Example 4 and Example 1 is only that: in step (1-2), the addition times of acylating agent a and acylating agent b are controlled to be 100 min.

[0100] The above two comparative examples mainly control the acylation reaction time. Since the acylation reaction is an exothermic reaction, it is preferably carried out at low temperature, and the feeding rate of raw materials is controlled to control the heat release. If the feeding is too fast, the raw materials, acid-binding agent, and catalyst will be instantaneously solidified, affecting the progress of the reaction; if the feeding time is too slow, it does not affect the progress of the reaction, but the time cost is high, resulting in unnecessary waste of resources.

[0101] Comparative Example 5

[0102] The difference between Comparative Example 5 and Example 1 is only that: in step (3), the polymerization reaction temperature is controlled to be 60 °C.

[0103] Comparative Example 6

[0104] The difference between Comparative Example 6 and Example 1 is only that: in step (3), the polymerization reaction temperature is controlled to be 100 °C.

[0105] The above two comparative examples mainly control the polymerization reaction temperature. Generally, in a polymerization reaction, the reaction rate is related to the reaction temperature. If the temperature is too low, the reaction is too slow; if the temperature is too high, the reaction is too fast, and the graft molecular weight of the polymer is too high, resulting in crosslinking and the formation of gel.

[0106] Using the Mannose-PSAS prepared in Examples 1-3 1 、Mannose-PSAS 2 、Mannose-PSAS 3 as dispersants to prepare carbon black slurries, and using commercial CTAB as a dispersant to prepare carbon black slurries, respectively test the relevant properties, and the test results are shown in Table 1.

[0107] Table 1 Properties of carbon black slurries prepared with the star polymers prepared in Examples 1-3 and CTAB as dispersants

[0108]

[0109]

[0110] Note: In the carbon black slurry, the carbon black particles account for 20% of the total mass of the slurry; the dosage of the dispersant is 4.0% - 5.0% of the total mass of the slurry; the mass ratio of deionized water is 1 - (20% - dispersant dosage ratio).

[0111] As can be seen from Table 1, compared with the commercial carbon black dispersant CTAB, the slurry prepared with the star polymer provided by the present invention as a carbon black dispersant has a lower slurry viscosity, and the viscosity increase after standing for 20 h is not large, indicating good stability. Comparing Examples 1-3, it can be seen that the addition amount of the second compound b (mannosyl vinyl monomer) is inversely proportional to the slurry stability.

[0112] Figure 2 is the gel permeation chromatography (GPC) distribution diagram of Mannose-PSAS prepared in Example 1 of the present invention 1 , as Figure 2 shown, the GPC distribution diagram is mainly concentrated within the retention time of 10 - 12 min, indicating that the reactant monomers have been completely converted into high molecular weight products, and the weight average molecular weight Mw is about 635 kDa. (Test conditions: Waters 1515 series gel permeation chromatography, the chromatographic column is composed of a 6*40 mm guard column, Ultrahydragel 250 and Ultrahydragel 500 columns in series, using 0.1 g / L NaNO 3 aqueous solution as the mobile phase, the flow rate is set at 1.0 mL / min, the injection volume is 20 μl, and the test temperature is 35°C. Using polyoxyethylene (33,600 - 868,000 Da) as the GPC analysis standard sample for calibration and analysis)

[0113] The present invention acylates a compound (the first compound) having a multi-branched main structural unit with an acylating agent, and uses the second compound a obtained from the acylation reaction as an initiator to initiate the polymerization reaction of a second compound b having a similar structure to obtain a high molecular weight non-linear star polymer; this star polymer can increase the electrostatic repulsion between particles through its own steric hindrance and molecular weight. Therefore, when it is applied to the dispersion of carbon black particles, the carbon black particles in the system can be stably present, and it has better dispersibility and stability compared with traditional low molecular weight surfactants, and has good application prospects in fields such as conductive carbon black pulping.

[0114] All aspects, embodiments, features and examples of the present invention should be considered illustrative in all respects and are not intended to limit the present invention, the scope of which is defined only by the claims. Without departing from the spirit and scope of the claimed invention, those skilled in the art will appreciate other embodiments, modifications and uses.

[0115] In addition, the inventors of this case also referred to the foregoing embodiments and conducted tests with other raw materials, process operations and process conditions described in this specification, and all obtained relatively ideal results.

[0116] Although the present invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions and / or additions can be made without departing from the spirit and scope of the present invention, and elements of the embodiments can be replaced with substantial equivalents. Additionally, many modifications can be made without departing from the scope of the present invention to adapt a particular situation or material to the teachings of the present invention. Therefore, the present invention is not intended to be limited to the specific embodiments disclosed for carrying out the present invention, but is intended to cover all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated, any use of the terms first, second, etc. does not denote any order or importance, but the terms first, second, etc. are used to distinguish one element from another.

Claims

1. A method for preparing a star polymer, characterized in that: comprising: providing a first compound having a plurality of branched chains; adding acylating agent a in batches to a solvent containing the first compound to form a mixed reaction solution, wherein the mass ratio of the first compound to acylating agent a is 1:1 to 1:23.6, and the addition time of acylating agent a is 30 to 100 min; subjecting the active groups on at least four branched chains of the first compound to an acylation reaction with acylating agent a at -2 to 25 °C to obtain a second compound a; adding acylating agent b in batches to a solvent containing the first compound to form a mixed reaction solution, wherein the mass ratio of the first compound to acylating agent b is 1:1 to 1:23.6, and the addition time of acylating agent b is 30 to 100 min; subjecting the active groups on at least four branched chains of the first compound to react with acylating agent b at least at -2 to 25 °C to obtain a second compound b; using the second compound a as an initiator to initiate the polymerization reaction of the second compound b with a compound containing an alkenyl group at 60 °C to 100 °C, and the mass ratio of the second compound b to the compound containing an alkenyl group is 1:2.2 to 1:50.4 to obtain a star polymer; wherein, the first compound is selected from one or more of mannose, pyromellitic acid, glucose, galactose, sorbose, and cyclodextrin having 6 to 8 units; the acylating agent a is a double-bond-free acylating agent, and the double-bond-free acylating agent is selected from one or more of chloroacetyl chloride, 2-bromo-2-methylpropionyl bromide, 2-chloro-2-methylpropionyl chloride, p-chlorobenzoyl chloride, chloroethyl chloroformate, and p-chlorophenyl chloroformate; the acylating agent b is a double-bond-containing acylating agent, and the double-bond-containing acylating agent is selected from one or more of allyl bromide, acryloyl chloride, acryloyl bromide, and 2-bromoethyl methacrylate.

2. The preparation method according to claim 1, characterized in that: the compound containing an alkenyl group includes one or more of allyl polyoxyethylene ether, ethyl acrylate, sodium vinylphenylmethanesulfonate, sodium allylsulfonate, sodium methallylsulfonate, vinyl acetate, sodium styrenesulfonate, and methyl methacrylate.

3. The preparation method of the star polymer according to claim 1, characterized in that: the first compound includes mannose, the acylating agent a includes chloroethyl chloroformate, the acylating agent b includes 2-bromoethyl methacrylate, and the compound containing an alkenyl group includes one or more of sodium allylsulfonate, ethyl acrylate, and sodium styrenesulfonate.

4. The preparation method of the star polymer according to claim 1, characterized in that: the solvent includes one or more of tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide.

5. The preparation method of the star polymer according to claim 1, characterized in that: the reaction time of the first compound with acylating agent a for the acylation reaction is 3 to 48 h, and the reaction time of the first compound with acylating agent b is 3 to 48 h.

6. The preparation method of the star polymer according to claim 1, characterized in that: The time of the polymerization reaction is 4 to 24 h.

7. A star polymer, which is characterized in that: it is prepared by the method described in any one of claims 1-6.

8. The star polymer according to claim 7, which is characterized in that: the weight-average molecular weight of the star polymer is greater than 100 kDa.

9. The star polymer according to claim 8, which is characterized in that: the weight-average molecular weight of the star polymer is 100 kDa - 700 kDa.

10. Use of the star polymer according to any one of claims 7-9 in dispersing carbon black particles.

11. A dispersant, which is characterized in that: it comprises the star polymer according to any one of claims 7-9.

12. A dispersion method, comprising: uniformly dispersing carbon black particles in a dispersant in the presence of a dispersant; which is characterized in that the dispersant contains the star polymer according to any one of claims 7-9.

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