A benzimidazole polyacrylic acid copolymer superdispersant, a preparation method and application thereof

Abstract

The application discloses a kind of based on benzimidazole polyacrylic acid copolymer hyperdispersant and its preparation method and application;Its structural formula is I, raw material includes styrene 10~32 parts, methacrylic acid 7~22 parts, vinylpyrrolidone 25~75 parts, N-amino benzimidazole 13~40 parts, initiator 4~15 parts, organic solvent 25~50 parts by weight;Preparation method is: styrene, methacrylic acid, vinylpyrrolidone monomer and initiator are added in organic solvent to form mixed solution 1 and 2 respectively;Mixed solution 2 and mixed solution 1 are simultaneously dropped to carry out polymerization reaction, then N-amino benzimidazole is added to react, finally cooling and charging;The copolymer hyperdispersant is formed anchoring effect on the surface of carbon nanotube by Π-Π electron effect, and simultaneously enough steric hindrance is formed between carbon nanotube particles by random coil structure of copolymer, and good dispersibility and stability of carbon nanotube are realized.

Description

Technical Field

[0001] This invention relates to a copolymer, its preparation method and application, and particularly to a benzimidazole-based polyacrylic acid copolymer superdispersant, its preparation method and application. Background Technology

[0002] Carbon nanotubes (CNTs), as a special type of low-dimensional material, have become ideal fillers and are widely used in polymer and other matrix materials to significantly improve the mechanical, electrical, thermal, and optical properties of products. However, a prerequisite for achieving this goal is the uniform dispersion of CNTs in the matrix material. Benzimazole, as a nitrogen-containing conjugated material, has excellent adsorption effects on CNTs, but current research mainly focuses on a series of modified materials with polybenzimidazole as the main chain. The high cost and stringent structural requirements make this type of material difficult to match with production applications.

[0003] Therefore, how to provide a dispersant with good dispersion performance and stable storage of CNTs, so as to achieve uniform dispersion of CNTs in matrix materials, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] Objectives of the Invention: The first objective of this invention is to provide a benzimidazole-based polyacrylic acid copolymer-based superdispersant for improving the dispersion stability of carbon nanotubes; the second objective of this invention is to provide a method for preparing the benzimidazole-based polyacrylic acid copolymer-based superdispersant; and the third objective of this invention is to provide the application of the benzimidazole-based polyacrylic acid copolymer-based superdispersant in carbon nanotubes.

[0005] Technical solution: The benzimidazole-based polyacrylic acid copolymer superdispersant of the present invention has the following structural formula:

[0006]

[0007] Where x = 1 to 3, y = 1 to 3, z = 2 to 7.

[0008] The benzimidazole groups on the copolymer side chains can form an anchoring effect on the carbon nanotube surface through the π-π electronic effect and by combining with substituents such as benzene rings, pyrrolidone rings, and amides. At the same time, the rigid structure of benzene rings and benzimidazoles, as well as the random coil structure of the copolymer, can effectively build sufficient steric hindrance between nanoparticles, thereby achieving the stability of carbon nanotubes in pigment paste.

[0009] The raw materials of the copolymer superdispersant include, by weight, 10-32 parts styrene, 7-22 parts methacrylic acid, 25-75 parts vinylpyrrolidone, 13-40 parts N-aminobenzimidazole, 4-15 parts initiator, and 25-50 parts organic solvent.

[0010] Preferably, the initiator is composed of one or two of benzoyl peroxide, tert-butyl peroxide, and azobisisobutyronitrile. The initiator can release free radicals when heated, causing a free radical copolymerization reaction between the raw materials.

[0011] Preferably, the organic solvent is methylpyrrolidone.

[0012] The preparation method of the benzimidazole-based polyacrylic acid copolymer superdispersant of the present invention includes the following steps:

[0013] (1) Styrene, methacrylic acid, and vinylpyrrolidone are added to an organic solvent to form a mixed solution 1;

[0014] (2) Add the initiator to the organic solvent to form a mixed solution 2;

[0015] (3) Mixed solution 2 and mixed solution 1 are added dropwise simultaneously to carry out the polymerization reaction. The reaction temperature is 90-140℃ and the reaction time is 6-10 hours.

[0016] (4) Reduce the temperature in step (3) to 50-80°C and slowly add N-aminobenzimidazole. React for 24-72 hours. After the reaction is complete, cool and load the material.

[0017] Preferably, in step (1) or (2), the mixed solution is formed by stirring to make the solution uniform, the stirring rate is 300-600 r / min, and the stirring time is 20-40 min.

[0018] Preferably, in step (3), the dripping time is 2 to 4 hours.

[0019] Preferably, in step (4), the time for adding N-aminobenzimidazole is 25 to 40 minutes.

[0020] The present invention relates to the application of benzimidazole-based polyacrylic acid copolymer in carbon nanotubes.

[0021] Preferably, the application in carbon nanotubes is: its application in the preparation of carbon nanotube color pastes.

[0022] The application method is as follows: add benzimidazole-based acrylic acid copolymer superdispersant and carbon nanotubes to methylpyrrolidone solvent, disperse, and grind to obtain carbon nanotube color paste product.

[0023] Preferably, the mass ratio of the benzimidazole acrylic acid copolymer superdispersant, carbon nanotubes and methylpyrrolidone solvent is 1-3:1-2:95-98.

[0024] Invention Mechanism: This invention uses benzimidazole as a modifying raw material and grafts it onto a copolymer composed of styrene, methacrylate, and vinylpyrrolidone. The benzimidazole groups on the copolymer side chains can bind to substituents such as benzene rings, pyrrolidone rings, and amides through the π-π electronic effect, forming an anchoring effect on the surface of carbon nanotubes. At the same time, the rigid structure of benzene rings and benzimidazole, as well as the random coil structure of the copolymer, can effectively build sufficient steric hindrance between carbon nanoparticles, thereby achieving the stability of carbon nanotubes in pigment pastes.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) Based on the benzimidazole polyacrylic acid copolymer superdispersant, it forms an anchoring effect on the surface of carbon nanotubes through the Π-Π electronic effect, and at the same time, it forms sufficient steric hindrance between carbon nanotube particles through the random coil structure of the copolymer, thus achieving good dispersibility and stability of carbon nanotubes; (2) The preparation method of the copolymer is simple and easy to industrialize; (3) When the copolymer superdispersant is applied to the dispersion of carbon nanotubes, the resulting CNTs pigment paste has uniform fineness and good storage stability. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the embodiments.

[0027] Example 1

[0028] The method for preparing the benzimidazole-modified polyacrylic acid copolymer superdispersant of the present invention includes the following steps:

[0029] (1) Accurately weigh 10.4 parts of styrene, 7.2 parts of methacrylic acid, 75 parts of vinylpyrrolidone, and 15 parts of organic solvent methylpyrrolidone, and stir at 300 r / min for 40 min to obtain mixed solution 1;

[0030] (2) Dissolve 4 parts of the initiator azobisisobutyronitrile in 10 parts of the organic solvent methylpyrrolidone to obtain mixed solution 2;

[0031] (3) Mixed solution 1 and mixed solution 2 were added dropwise simultaneously at 90°C. The addition was completed within 3 hours, and the polymerization reaction was maintained at this temperature for 6 hours until the reaction was complete.

[0032] (4) When the temperature drops to 50°C, slowly add 13.3 parts of N-aminobenzimidazole over 30 minutes and continue the reaction for 24 hours. Gradually cool and load the material to obtain the benzimidazole-modified polyacrylic acid copolymer superdispersant.

[0033] Example 2

[0034] The method for preparing the benzimidazole-modified polyacrylic acid copolymer superdispersant of the present invention includes the following steps:

[0035] (1) Accurately weigh 31.2 parts of styrene, 10.8 parts of methacrylic acid, 55 parts of vinylpyrrolidone, and 40 parts of organic solvent methylpyrrolidone, and stir at 300 r / min for 40 min to obtain mixed solution 1;

[0036] (2) Then, 7.5 parts of the initiator benzoyl peroxide were dissolved in 15 parts of the organic solvent methylpyrrolidone to obtain mixed solution 2;

[0037] (3) Mixed solution 1 and mixed solution 2 were added dropwise simultaneously at 110℃. The addition was completed within 2.5 hours, and the polymerization reaction was maintained at this temperature for 8 hours until the reaction was complete.

[0038] (4) Lower the temperature to 60°C and slowly add 16.7 parts of N-aminobenzimidazole over 30 minutes, and continue the reaction for 36 hours. Gradually cool and load the material to obtain benzimidazole-modified polyacrylic acid copolymer superdispersant.

[0039] Example 3

[0040] The method for preparing the benzimidazole-modified polyacrylic acid copolymer superdispersant of the present invention includes the following steps:

[0041] (1) Accurately weigh 31.2 parts of styrene, 7.2 parts of methacrylic acid, 25 parts of vinylpyrrolidone, and 35 parts of organic solvent methylpyrrolidone, and stir at 300 r / min for 40 min to obtain mixed solution 1;

[0042] (2) Then, 5 parts of the initiator azobisisobutyronitrile and 3 parts of tert-butyl peroxide were dissolved in 15 parts of the organic solvent methylpyrrolidone to obtain mixed solution 2.

[0043] (3) Mixed solution 1 and mixed solution 2 are added dropwise at 100°C and the addition is completed within 2 hours. The temperature is gradually increased to 130°C and the polymerization reaction is carried out continuously for 10 hours until the reaction is completed.

[0044] (4) Lower the temperature to 70°C and slowly add 13.3 parts of N-aminobenzimidazole over 30 minutes, and continue the reaction for 36 hours. Gradually cool and load the material to obtain the benzimidazole-modified polyacrylic acid copolymer superdispersant.

[0045] Example 4

[0046] The method for preparing the benzimidazole-modified polyacrylic acid copolymer superdispersant of the present invention includes the following steps:

[0047] (1) Accurately weigh 31.2 parts of styrene, 21.6 parts of methacrylic acid, 60 parts of vinylpyrrolidone, and 25 parts of organic solvent methylpyrrolidone, and stir at 300 r / min for 40 min to obtain mixed solution 1;

[0048] (2) Then, 5 parts of the initiator azobisisobutyronitrile and 3 parts of benzoyl peroxide were dissolved in 15 parts of the organic solvent methylpyrrolidone to obtain mixed solution 2;

[0049] (3) Mixed solution 1 and mixed solution 2 are added dropwise at 90°C and the addition is completed within 4 hours. The temperature is gradually increased to 110°C and the polymerization reaction is carried out continuously for 10 hours until the reaction is completed.

[0050] (4) The temperature was lowered to 80°C, and 39.9 parts of N-aminobenzimidazole were slowly added dropwise over 30 minutes. The reaction was continued for 72 hours. The mixture was gradually cooled and loaded to obtain a benzimidazole-modified polyacrylic acid copolymer superdispersant.

[0051] Example 5

[0052] The method for preparing the benzimidazole-modified polyacrylic acid copolymer superdispersant of the present invention includes the following steps:

[0053] (1) Accurately weigh 31.2 parts of styrene, 14.4 parts of methacrylic acid, 55 parts of vinylpyrrolidone, and 25 parts of organic solvent methylpyrrolidone, and stir at 300 r / min for 40 min to obtain mixed solution 1;

[0054] (2) Then, 8 parts of the initiator benzoyl peroxide and 7 parts of tert-butyl peroxide were dissolved in 25 parts of the organic solvent methylpyrrolidone to obtain mixed solution 2;

[0055] (3) Mixed solution 1 and mixed solution 2 are added dropwise at 120°C. The addition is completed within 4 hours, and the polymerization reaction is maintained at this temperature for 10 hours until the reaction is complete.

[0056] (4) The temperature was lowered to 80°C, and 26.7 parts of N-aminobenzimidazole were slowly added dropwise over 30 minutes. The reaction was continued for 72 hours. The mixture was gradually cooled and loaded to obtain a benzimidazole-modified polyacrylic acid copolymer superdispersant.

[0057] Performance testing

[0058] The benzimidazole-modified polyacrylic acid copolymer superdispersant obtained in Examples 1-5 of this invention, a commercially available dispersant, polyvinylpyrrolidone, carbon nanotubes, and methylpyrrolidone were dissolved at a weight ratio of 1.5:1:98, and ultrasonically dispersed for 6 hours under ultrasonic conditions. Then, the mixture was ground in a ball mill for 12 hours to obtain the carbon nanotube color paste. The particle size distribution of the carbon nanotubes in the color paste was tested using a dispersibility tester, and the test results are shown in Table 1.

[0059] Table 1. Test Results of Examples and Comparative Data

[0060]

[0061] Table 1 shows that the benzimidazole-modified polyacrylic acid copolymer superdispersants prepared in Examples 1-5, when used to prepare carbon nanotube color pastes, produced stable color pastes that did not separate after 720 hours of storage. Testing revealed that the carbon nanotube particle size distribution in the color pastes did not change significantly over time, which was significantly better than that of polyvinylpyrrolidone and commercially available dispersants.

Claims

1. A benzimidazole-based polyacrylic acid copolymer superdispersant, characterized in that, The raw materials for the copolymer superdispersant, by weight, include 10-32 parts styrene, 7-22 parts methacrylic acid, 25-75 parts vinylpyrrolidone, 13-40 parts N-aminobenzimidazole, 4-15 parts initiator, and 25-50 parts organic solvent; the preparation method includes the following steps: (1) Styrene, methacrylic acid, and vinylpyrrolidone are added to an organic solvent to form a mixed solution 1; (2) Add the initiator to the organic solvent to form a mixed solution 2; (3) Mixed solution 2 and mixed solution 1 are added dropwise simultaneously to carry out the polymerization reaction. The reaction temperature is 90~140℃ and the reaction time is 6~10 hours. (4) Reduce the temperature in step (3) to 50~80℃ and slowly add N-aminobenzimidazole. React for 24~72 hours. After the reaction is complete, cool and load the material.

2. The benzimidazole-based polyacrylic acid copolymer superdispersant according to claim 1, wherein the initiator is composed of one or two of benzoyl peroxide, tert-butyl peroxide, and azobisisobutyronitrile.

3. The benzimidazole-based polyacrylic acid copolymer superdispersant according to claim 1, wherein the organic solvent is methylpyrrolidone.

4. A method for preparing a benzimidazole-based polyacrylic acid copolymer superdispersant as described in any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Styrene, methacrylic acid, and vinylpyrrolidone are added to an organic solvent to form a mixed solution 1; (2) Add the initiator to the organic solvent to form a mixed solution 2; (3) Mixed solution 2 and mixed solution 1 are added dropwise simultaneously to carry out the polymerization reaction. The reaction temperature is 90~140℃ and the reaction time is 6~10 hours. (4) Reduce the temperature in step (3) to 50~80℃ and slowly add N-aminobenzimidazole. React for 24~72 hours. After the reaction is complete, cool and load the material.

5. The preparation method of the benzimidazole-based polyacrylic acid copolymer superdispersant according to claim 4, characterized in that, In step (3), the dripping time is 2 to 4 hours.

6. The application of the benzimidazole-based polyacrylic acid copolymer hyperdispersant as described in any one of claims 1 to 3 in carbon nanotubes.

7. The application according to claim 6, characterized in that, The application in carbon nanotubes is as follows: its application in the preparation of carbon nanotube color pastes.

8. The application according to claim 7, characterized in that, The application method is as follows: add benzimidazole-based acrylic acid copolymer superdispersant and carbon nanotubes to methylpyrrolidone solvent, disperse, and grind to obtain carbon nanotube color paste product.

9. The application according to claim 8, characterized in that, The application method is as follows: the mass ratio of the benzimidazole acrylic acid copolymer superdispersant, carbon nanotubes and methylpyrrolidone solvent is 1~3:1~2:95~98.

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