Polymer conductive microsphere and preparation method thereof

Abstract

The invention discloses a polymer conductive microsphere and a preparation method thereof, and belongs to the technical field of conductive microspheres. The polymer conductive microsphere is prepared from the following raw materials in parts by weight: 30 to 50 parts of styrene, 20 to 40 parts of divinyl benzene, 0.5 to 1.5 parts of macromolecular initiator, 2 to 6 parts of stabilizer, 4 to 6 parts of foaming agent, 10 to 12 parts of Mxene material, 80 parts of deionized water and 200 parts of methylbenzene. The preparation method comprises the following steps: reacting glycidol with 2-bromoisobutyryl bromide to prepare an intermediate 1, then grafting 4-(diethylamino) salicylaldehyde on chitosan oligosaccharide to prepare an intermediate 2, and finally reacting with the intermediate 2 in the intermediate 1 to prepare the macromolecular initiator. The polymer conductive microspheres prepared by the method have good conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive microspheres, and specifically relates to a polymer conductive microsphere and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology, the demand for high-performance conductive materials is becoming increasingly urgent. As an important conductive material, polymer conductive microspheres have broad application prospects in fields such as microelectrode connection of electronic devices and anisotropic conductive adhesives. In electronic devices, anisotropic conductive materials are the bridges for connecting microelectrodes, usually composed of conductive microspheres and adhesive resins. Among them, the uniformity, mechanical properties, and electrical conductivity of conductive microspheres are the key factors affecting the quality and performance of anisotropic conductive materials. However, there are many problems in the existing preparation methods of conductive microspheres. For example, the commonly used electroless plating method requires roughening and sensitizing treatment of polymer microspheres, which not only has a complex process, high danger, but also has cumbersome post-treatment, increasing production costs and environmental risks. In addition, the functionalization method will also have an obvious impact on the process of conductive microspheres. Therefore, developing an environmentally friendly, low-cost polymer conductive microsphere with good electrical conductivity is of great significance for meeting the demand of the development of electronic information technology for high-performance conductive materials.

[0003] Chinese Patent Invention No. CN115109277A discloses a conductive microsphere with a surface protrusion structure, a preparation method and an application thereof. The preparation method includes: carrying out a polymerization reaction on a core microsphere and a monomer in the presence of an initiator, a surfactant and a solvent to obtain a polymer-coated microsphere with a surface protrusion structure. This preparation method not only increases production costs, but also generates strongly irritating vapors during the functionalization process, endangering the environment and human health. At the same time, the electrical conductivity of the conductive microsphere is average. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a polymer conductive microsphere and a preparation method thereof.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions: A polymer conductive microsphere, comprising the following raw materials in parts by weight: Styrene: 30 - 50 parts, divinylbenzene: 20 - 40 parts, macroinitiator: 0.5 - 1.5 parts, stabilizer: 2 - 6 parts, foaming agent: 4 - 6 parts, Mxene material: 10 - 12 parts, deionized water: 80 parts, toluene: 200 parts; The macroinitiator is prepared by the following method: S1: Add dichloromethane, glycidol, triethylamine into a reactor, stir, and slowly drop 2-bromoisobutyryl bromide in an ice bath. React for 2 - 4 h, then raise the temperature to room temperature and continue to react for 8 - 10 h. After post-treatment, intermediate 1 is obtained. S2: Chitosan oligosaccharide reacts with 4-(diethylamino)salicylaldehyde under the action of the catalyst glacial acetic acid to obtain intermediate 2. S3: Add pyridine, intermediate 1, and intermediate 2 into a reactor in sequence, stir to mix evenly, raise the temperature to 80 - 120 °C, add sodium hydride, react for 4 - 6 h, and obtain the macromolecular initiator after post-treatment.

[0006] In step S1, the feeding mass ratio of dichloromethane, glycidol, and 2-bromoisobutyryl bromide is 30:(6 - 8):(8 - 10). In step S2, the feeding mass ratio of chitosan oligosaccharide and 4-(diethylamino)salicylaldehyde is 10:(3 - 4.5). In step S3, the feeding mass ratio of intermediate 1 and intermediate 2 is (3 - 4):10.

[0007] The stabilizer is one of polyethyleneimine and polyvinylpyrrolidone.

[0008] The foaming agent is one of magnesium carbonate, sodium bicarbonate, and sodium dodecyl sulfate.

[0009] A preparation method of polymer conductive microspheres includes the following steps: S1: Weigh by weight: styrene: 30 - 50 parts, divinylbenzene: 20 - 40 parts, macromolecular initiator: 0.5 - 1.5 parts, stabilizer: 2 - 6 parts, foaming agent: 4 - 6 parts, Mxene material: 10 - 12 parts, deionized water: 80 parts, toluene: 200 parts. S2: Add toluene, styrene, divinylbenzene, stabilizer, macromolecular initiator, and foaming agent into a reactor, introduce nitrogen, disperse by ultrasonic wave, raise the temperature to 80 - 100 °C, and react for 10 - 16 h to obtain a mixed solution A. S3: Add the Mxene material into deionized water, mix evenly by ultrasonic wave to obtain a mixed solution B. Slowly add the mixed solution A into the mixed solution B, raise the temperature to 100 - 120 °C, and react for 16 - 20 h. After post-treatment, polymer conductive microspheres are obtained.

[0010] Due to the above technical solutions, the beneficial effects of the present invention include: (1) First, the present invention prepared intermediate 1 by reacting the hydroxyl group in glycidol with the acyl bromide in 2-bromo-2-methylpropionyl bromide. Then, a Schiff base reaction was carried out between the amino group on chitosan oligosaccharide and the aldehyde group in 4-(diethylamino)salicylaldehyde to prepare intermediate 2. Finally, the epoxy group in intermediate 1 reacted with the hydroxyl group in intermediate 2 to prepare a macromolecular initiator.

[0011] (2) For the macromolecular initiator prepared by the present invention, since the matrix used is chitosan oligosaccharide, which has abundant active groups such as amino and hydroxyl groups on its molecular chain, and has good biodegradability and biocompatibility. By grafting bromine atoms onto chitosan oligosaccharide, the molecular weight of the initiator is increased. During the polymerization reaction process, the volatilization of the initiator can be reduced, the efficiency and controllability of the polymerization reaction can be improved, and the negative impact on the environment can be reduced. Introducing 4-(diethylamino)salicylaldehyde into chitosan oligosaccharide can improve the solubility of chitosan oligosaccharide in organic solvents, and it can be better dispersed in the reaction system of microspheres, thereby improving the uniformity and efficiency of the polymerization reaction, and making the particle size of the prepared polymer microspheres more uniform and controllable.

[0012] (3) The present invention adsorbs a large amount of Mxene material on the surface of conductive microspheres. The d-orbital electrons of the transition metal Ti layer in the Mxene material endow it with a high electron density near the Fermi level, making the Mxene material have good conductivity and improving the conductivity of the conductive microspheres. Specific Embodiments

[0013] The following is further illustrated with reference to embodiments, but the present invention is not limited to these embodiments.

[0014] Example 1 Preparation of Macromolecular Initiator: S1: Add 300 g of dichloromethane, 60 g of glycidol, and 80 g of triethylamine to a reactor, stir, and slowly drop 80 g of 2-bromo-2-methylpropionyl bromide in an ice bath. The dropping takes 10 min, and the reaction lasts for 2 h. Then, raise the temperature to room temperature and continue the reaction for 8 h. After the reaction is completed, wash with deionized water until neutral, let it stand for layering, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, and carry out vacuum distillation at 60 °C for 3 h to obtain intermediate 1, and its structural formula is as follows:

[0015] The nuclear magnetic resonance hydrogen spectrum data thereof are as follows: 11H NMR (500 MHz, Chloroform-d) δ 4.33–4.08 (dd, J = 11.4, 2.6 Hz, 2H), 3.70 – 3.42 (m, 1H), 3.09 (ddd, J = 125.2, 7.6, 3.1 Hz, 2H), 1.94 (d, J = 3.9 Hz, 6H). S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 30 g of 4-(diethylamino)salicylaldehyde into the reactor, stir to dissolve, heat up to 70 °C, then add 1 ml of glacial acetic acid, reflux for 5 h. After the reaction is completed, let it stand and filter, then wash three times with methanol (30 g of methanol each time), and dry in vacuum at 50 °C for 5 h to obtain Intermediate 2, with a number average molecular weight of 3560; S3: Add 350 g of pyridine, 30 g of Intermediate 1, and 100 g of Intermediate 2 into the reactor in sequence, stir evenly, heat up to 80 °C, add 6 g of sodium hydride, react for 6 h, rotary evaporate at 50 °C for 1.5 h, then add 800 ml of deionized water and stir evenly, then extract three times with n-butanol (500 ml of n-butanol each time), distill under reduced pressure at 60 °C for 1.5 h, and finally separate with a silica gel chromatographic column to obtain the macromolecular initiator, with a number average molecular weight of 4410.

[0016] Example 2 Preparation of macromolecular initiator: S1: Add 300 g of dichloromethane, 70 g of glycidol, and 90 g of triethylamine into the reactor, stir, and slowly add 90 g of 2-bromoisobutyryl bromide dropwise in an ice bath over 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, let it stand and separate layers, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, and distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 40 g of 4-(diethylamino)salicylaldehyde into the reactor, stir to dissolve, heat up to 60 °C, then add 2 ml of glacial acetic acid, reflux for 6 h. After the reaction is completed, let it stand and filter, then wash three times with methanol (30 g of methanol each time), and dry in vacuum at 60 °C for 4 h to obtain Intermediate 2, with a number average molecular weight of 3780; S3: Add 350 g of pyridine, 35 g of intermediate 1, and 100 g of intermediate 2 into the reactor in sequence, stir to mix evenly, heat up to 95 °C, add 8 g of sodium hydride, react for 5 h, perform rotary evaporation at 60 °C for 1 h, then add 800 ml of deionized water and stir to mix evenly, then extract three times with n-butanol (500 ml of n-butanol is used each time), perform vacuum distillation at 70 °C for 1 h, and finally separate with a silica gel chromatography column to obtain the macroinitiator, with a number-average molecular weight of 4970.

[0017] Example 3 Preparation of macroinitiator: S1: Add 300 g of dichloromethane, 80 g of glycidol, and 100 g of triethylamine into the reactor, stir, and slowly dropwise add 100 g of 2-bromoisobutyryl bromide in an ice bath. The dropping takes 15 min, react for 4 h, then raise the temperature to room temperature and continue to react for 10 h. After the reaction is completed, wash with deionized water until neutral, let it stand for layering, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, perform vacuum distillation at 80 °C for 1 h to obtain intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 45 g of 4-(diethylamino)salicylaldehyde into the reactor, stir to dissolve, heat up to 50 °C, then add 3 ml of glacial acetic acid, reflux and react for 7 h. After the reaction is completed, let it stand and perform suction filtration, then wash three times with methanol (30 g of methanol is used each time), and perform vacuum drying at 70 °C for 3 h to obtain intermediate 2, with a number-average molecular weight of 3960; S3: Add 350 g of pyridine, 40 g of intermediate 1, and 100 g of intermediate 2 into the reactor in sequence, stir to mix evenly, heat up to 105 °C, add 10 g of sodium hydride, react for 4 h, perform rotary evaporation at 70 °C for 40 min, then add 800 ml of deionized water and stir to mix evenly, then extract three times with n-butanol (500 ml of n-butanol is used each time), perform vacuum distillation at 80 °C for 40 min, and finally separate with a silica gel chromatography column to obtain the macroinitiator, with a number-average molecular weight of 5250.

[0018] Example 4 Preparation of polymer conductive microspheres: S1: Weigh: 300 g of styrene, 200 g of divinylbenzene, 5 g of macroinitiator (prepared in Example 1), 20 g of stabilizer (polyethyleneimine), 40 g of foaming agent (magnesium carbonate), 100 g of Mxene material, 800 g of deionized water, 2000 g of toluene; S2: Add toluene, styrene, divinylbenzene, stabilizer, macroinitiator, and foaming agent into the reactor, introduce nitrogen, perform ultrasonic dispersion, heat up to 80 °C, and react for 16 h to obtain the mixed solution A; S3: Dissolve the Mxene material in deionized water, mix evenly by ultrasonic treatment to obtain mixed solution B. Slowly add mixed solution A to mixed solution B, dropwise add for 10 min, heat up to 100 °C, react for 20 h, centrifuge, and then wash successively with 200 ml of deionized water, 200 ml of ethanol, and 200 ml of acetonitrile solution, and vacuum dry at 70 °C for 3 h to obtain polymer conductive microspheres.

[0019] Example 5 Preparation of polymer conductive microspheres: S1: Weigh: 400 g of styrene, 300 g of divinylbenzene, 8 g of macromolecular initiator (prepared in Example 2), 40 g of stabilizer (polyvinylpyrrolidone PVP K25), 50 g of foaming agent (sodium bicarbonate), 110 g of Mxene material, 800 g of deionized water, and 2000 g of toluene; S2: Add toluene, styrene, divinylbenzene, stabilizer, macromolecular initiator, and foaming agent to the reactor, introduce nitrogen, disperse by ultrasonic treatment, heat up to 90 °C, and react for 13 h to obtain mixed solution A; S3: Dissolve the Mxene material in deionized water, mix evenly by ultrasonic treatment to obtain mixed solution B. Slowly add mixed solution A to mixed solution B, dropwise add for 10 min, heat up to 110 °C, react for 18 h, centrifuge, and then wash successively with 200 ml of deionized water, 200 ml of ethanol, and 200 ml of acetonitrile solution, and vacuum dry at 70 °C for 3 h to obtain polymer conductive microspheres.

[0020] Example 6 Preparation of polymer conductive microspheres: S1: Weigh: 500 g of styrene, 400 g of divinylbenzene, 10 g of macromolecular initiator (prepared in Example 3), 60 g of stabilizer (polyvinylpyrrolidone PVP K30), 60 g of foaming agent (sodium dodecyl sulfate), 120 g of Mxene material, 800 g of deionized water, and 2000 g of toluene; S2: Add toluene, styrene, divinylbenzene, stabilizer, macromolecular initiator, and foaming agent to the reactor, introduce nitrogen, disperse by ultrasonic treatment, heat up to 100 °C, and react for 10 h to obtain mixed solution A; S3: Dissolve the Mxene material in deionized water, mix evenly by ultrasonic treatment to obtain mixed solution B. Slowly add mixed solution A to mixed solution B, dropwise add for 10 min, heat up to 120 °C, react for 16 h, centrifuge, and then wash successively with 200 ml of deionized water, 200 ml of ethanol, and 200 ml of acetonitrile solution, and vacuum dry at 70 °C for 3 h to obtain polymer conductive microspheres.

[0021] Comparative Example 1 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator added in the components is replaced with AIBN of equal weight.

[0022] Comparative Example 2 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with a macroinitiator of equal weight prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, and 90 g of triethylamine to the reactor, stir, slowly add 90 g of 2-bromoisobutyryl bromide dropwise in an ice bath for 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, let it stand and separate layers, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, and distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 24 g of 4-(diethylamino)salicylaldehyde to the reactor, stir and dissolve, raise the temperature to 60 °C, then add 2 ml of glacial acetic acid, and reflux for 6 h. After the reaction is completed, let it stand and filter by suction, then wash three times with methanol (30 g of methanol each time), and dry in vacuo at 60 °C for 4 h to obtain Intermediate 2, with a number average molecular weight of 3350; S3: Add 350 g of pyridine, 37 g of Intermediate 1, and 100 g of Intermediate 2 to the reactor in sequence, stir and mix evenly, raise the temperature to 95 °C, add 8 g of sodium hydride, react for 5 h, rotate and evaporate at 60 °C for 1 h, then add 800 ml of deionized water and stir and mix evenly, then extract three times with n-butanol (500 ml of n-butanol each time), distill under reduced pressure at 70 °C for 1 h, and finally separate by a silica gel chromatography column to obtain the macroinitiator, with a number average molecular weight of 4470.

[0023] Comparative Example 3 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with a macroinitiator of equal weight prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, and 90 g of triethylamine to the reactor, stir, slowly add 90 g of 2-bromoisobutyryl bromide dropwise in an ice bath for 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, let it stand and separate layers, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, and distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 60 g of 4-(diethylamino)salicylaldehyde into the reactor, stir to dissolve, heat up to 60 °C, then add 2 ml of glacial acetic acid, reflux for 6 h. After the reaction, let it stand and filter by suction, then wash three times with methanol (30 g of methanol each time), and dry in vacuum at 60 °C for 4 h to obtain Intermediate 2, with a number average molecular weight of 4290; S3: Add 350 g of pyridine, 29 g of Intermediate 1, and 100 g of Intermediate 2 into the reactor in sequence, stir to mix evenly, heat up to 95 °C, add 8 g of sodium hydride, react for 5 h, perform rotary evaporation at 60 °C for 1 h, then add 800 ml of deionized water and stir to mix evenly, then extract three times with n-butanol (500 ml of n-butanol each time), distill under reduced pressure at 70 °C for 1 h, and finally separate by silica gel chromatography column to obtain the macromolecular initiator, with a number average molecular weight of 5410.

[0024] Comparative Example 4 A polymer conductive microsphere has the same raw material composition and process as in Example 5, except that the macromolecular initiator is replaced with an equal weight of macromolecular initiator prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, and 90 g of triethylamine into the reactor, stir, and slowly drop 90 g of 2-bromoisobutyryl bromide in an ice bath over 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction, wash with deionized water until neutral, let it stand and separate layers, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, and distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 40 g of 4-(diethylamino)salicylaldehyde into the reactor, stir to dissolve, heat up to 60 °C, then add 2 ml of glacial acetic acid, reflux for 6 h. After the reaction, let it stand and filter by suction, then wash three times with methanol (30 g of methanol each time), and dry in vacuum at 60 °C for 4 h to obtain Intermediate 2, with a number average molecular weight of 3780; S3: Add 350 g of pyridine, 20 g of Intermediate 1, and 100 g of Intermediate 2 into the reactor in sequence, stir to mix evenly, heat up to 95 °C, add 8 g of sodium hydride, react for 5 h, perform rotary evaporation at 60 °C for 1 h, then add 800 ml of deionized water and stir to mix evenly, then extract three times with n-butanol (500 ml of n-butanol each time), distill under reduced pressure at 70 °C for 1 h, and finally separate by silica gel chromatography column to obtain the macromolecular initiator, with a number average molecular weight of 4380.

[0025] Comparative Example 5 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with an equal weight of macroinitiator prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, and 90 g of triethylamine to the reactor, stir, slowly add 90 g of 2-bromoisobutyryl bromide dropwise in an ice bath, the dropping time is 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, let it stand and separate layers, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, and distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 40 g of 4-(diethylamino)salicylaldehyde to the reactor, stir to dissolve, raise the temperature to 60 °C, then add 2 ml of glacial acetic acid, reflux and react for 6 h. After the reaction is completed, let it stand and filter by suction, then wash three times with methanol (30 g of methanol is used each time), and dry in vacuo at 60 °C for 4 h to obtain Intermediate 2, and the number average molecular weight is 3780; S3: Add 350 g of pyridine, 53 g of Intermediate 1, and 100 g of Intermediate 2 to the reactor in sequence, stir and mix evenly, raise the temperature to 95 °C, add 8 g of sodium hydride, react for 6 h, rotate and evaporate at 60 °C for 1 h, then add 800 ml of deionized water and stir and mix evenly, then extract three times with n-butanol (500 ml of n-butanol is used each time), distill under reduced pressure at 70 °C for 1 h, and finally separate with a silica gel chromatographic column to obtain the macroinitiator, and the number average molecular weight is 5510.

[0026] Comparative Example 6 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with an equal weight of macroinitiator prepared by the following method: S1: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 40 g of 4-(diethylamino)salicylaldehyde to the reactor, stir to dissolve, raise the temperature to 60 °C, then add 2 ml of glacial acetic acid, reflux and react for 6 h. After the reaction is completed, let it stand and filter by suction, then wash three times with methanol (30 g of methanol is used each time), and dry in vacuo at 60 °C for 4 h to obtain Intermediate 2; S2: Add 350 g of pyridine, 35 g of 2-bromoisobutyryl bromide, and 100 g of Intermediate 2 to the reactor in sequence, stir and mix evenly, raise the temperature to 95 °C, add 8 g of sodium hydride, react for 5 h, rotate and evaporate at 60 °C for 1 h, then add 800 ml of deionized water and stir and mix evenly, then extract three times with n-butanol (500 ml of n-butanol is used each time), distill under reduced pressure at 70 °C for 1 h, and finally separate with a silica gel chromatographic column to obtain the macroinitiator.

[0027] Comparative Example 7 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with an equal weight of a macroinitiator prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, 90 g of triethylamine to the reactor, stir, slowly dropwise add 90 g of 2-bromoisobutyryl bromide in an ice bath, the dropping time is 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, stand for stratification, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 350 g of pyridine, 100 g of chitosan oligosaccharide, 35 g of Intermediate 1 to the reactor in sequence, stir and mix evenly, raise the temperature to 95 °C, add 8 g of sodium hydride, react for 5 h, after rotary evaporation at 60 °C for 1 h, add 800 ml of deionized water and stir and mix evenly, then extract with n-butanol three times (500 ml of n-butanol is used each time), distill under reduced pressure at 70 °C for 1 h, and finally separate by a silica gel chromatographic column to obtain the macroinitiator.

[0028] Comparative Example 8 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with an equal weight of a macroinitiator prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, 90 g of triethylamine to the reactor, stir, slowly dropwise add 90 g of 2-bromoisobutyryl bromide in an ice bath, the dropping time is 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, stand for stratification, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, 40 g of salicylaldehyde to the reactor, stir to dissolve, raise the temperature to 60 °C, then add 2 ml of glacial acetic acid, reflux and react for 6 h. After the reaction is completed, let it stand and filter, then wash with methanol three times (30 g of methanol is used each time), and dry in vacuo at 60 °C for 4 h to obtain Intermediate 2; S3: Add 350 g of pyridine, 35 g of Intermediate 1, 100 g of Intermediate 2 to the reactor in sequence, stir and mix evenly, raise the temperature to 95 °C, add 8 g of sodium hydride, react for 5 h, after rotary evaporation at 60 °C for 1 h, add 800 ml of deionized water and stir and mix evenly, then extract with n-butanol three times (500 ml of n-butanol is used each time), distill under reduced pressure at 70 °C for 1 h, and finally separate by a silica gel chromatographic column to obtain the macroinitiator.

[0029] Comparative Example 9 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with an equal weight of a macroinitiator prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, and 90 g of triethylamine to the reactor, stir, slowly add 90 g of dichloroacetyl chloride dropwise in an ice bath, the dropping time is 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, stand for liquid separation, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, and distill under reduced pressure at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan oligosaccharide, and 40 g of 4-(diethylamino)salicylaldehyde to the reactor, stir and dissolve, raise the temperature to 60 °C, then add 2 ml of glacial acetic acid, reflux and react for 6 h. After the reaction is completed, let it stand and filter by suction, then wash three times with methanol (30 g of methanol is used each time), and dry in vacuo at 60 °C for 4 h to obtain Intermediate 2; S3: Add 350 g of pyridine, 35 g of Intermediate 1, and 100 g of Intermediate 2 to the reactor in sequence, stir and mix evenly, raise the temperature to 95 °C, add 8 g of sodium hydride, react for 5 h, after rotary evaporation at 60 °C for 1 h, add 800 ml of deionized water and stir and mix evenly, then extract three times with n-butanol (500 ml of n-butanol is used each time), distill under reduced pressure at 70 °C for 1 h, and finally separate by a silica gel chromatographic column to obtain the macroinitiator.

[0030] Comparative Example 10 A polymer conductive microsphere, the raw material composition and process are basically the same as those in Example 5, the difference is that the macroinitiator is replaced with an equal weight of a macroinitiator prepared by the following method: S1: Add 200 g of N,N-dimethylacetamide / lithium chloride solvent (150 g of N,N-dimethylacetamide, 50 g of lithium chloride), 40 g of chitosan, and 90 g of 4-(diethylamino)salicylaldehyde to the reactor, stir and dissolve, raise the temperature to 60 °C, then add 2 ml of glacial acetic acid, reflux and react for 6 h. After the reaction is completed, let it stand and filter by suction, then wash three times with methanol (30 g of methanol is used each time), and dry in vacuo at 60 °C for 4 h to obtain Intermediate 3; S2: Add 350 g of pyridine, 35 g of 2-bromo-2-methylpropanoyl bromide, and 100 g of Intermediate 3 into the reactor in sequence, stir to mix evenly, heat up to 95 °C, add 8 g of sodium hydride, react for 5 h, perform rotary evaporation at 60 °C for 1 h, then add 800 ml of deionized water and stir to mix evenly. Then extract with n-butanol three times (500 ml of n-butanol each time), perform vacuum distillation at 70 °C for 1 h, and finally separate by silica gel chromatography column to obtain the macroinitiator.

[0031] Comparative Example 11 A polymer conductive microsphere has the same raw material composition and process as in Example 5, except that the macroinitiator is replaced with an equal weight of macroinitiator prepared by the following method: S1: Add 300 g of dichloromethane, 70 g of glycidol, and 90 g of triethylamine into the reactor, stir, and slowly drop 90 g of 2-bromo-2-methylpropanoyl bromide in an ice bath. The dropping time is 12 min, react for 3 h, then raise the temperature to room temperature and continue to react for 9 h. After the reaction is completed, wash with deionized water until neutral, let it stand and separate layers, remove the aqueous phase, dry the organic phase with 50 g of anhydrous magnesium sulfate for 4 h, filter, perform vacuum distillation at 70 °C for 2 h to obtain Intermediate 1; S2: Add 300 g of N,N-dimethylacetamide / lithium chloride solvent (225 g of N,N-dimethylacetamide, 75 g of lithium chloride), 100 g of chitosan, and 40 g of 4-(diethylamino)salicylaldehyde into the reactor, stir to dissolve, heat up to 60 °C, then add 2 ml of glacial acetic acid, and reflux and react for 6 h. After the reaction is completed, let it stand and perform suction filtration, then wash with methanol three times (30 g of methanol each time), and perform vacuum drying at 60 °C for 4 h to obtain Intermediate 4; S3: Add 350 g of pyridine, 35 g of Intermediate 1, and 100 g of Intermediate 4 into the reactor in sequence, stir to mix evenly, heat up to 95 °C, add 8 g of sodium hydride, react for 5 h, perform rotary evaporation at 60 °C for 1 h, then add 800 ml of deionized water and stir to mix evenly. Then extract with n-butanol three times (500 ml of n-butanol each time), perform vacuum distillation at 70 °C for 1 h, and finally separate by silica gel chromatography column to obtain the macroinitiator.

[0032] Comparative Example 12 A conductive microsphere with a surface protrusion structure prepared by using the raw material composition, ratio, and method of Example 1 of the Chinese invention patent with the publication number CN115109277A.

[0033] The preparation method of the Mxene material used in this application is as follows: Add 2 g of lithium fluoride and 40 mL of 9 mol / L hydrochloric acid into a polytetrafluoroethylene beaker, stir for 30 min to mix evenly, slowly add 2 g of MAX-Ti3AlC2 to the mixed solution, heat up to 35 °C, and magnetically stir at 400 rpm for 24 h; centrifuge the reaction solution to remove the supernatant and add 20 ml of deionized water, and ultrasonicate to obtain multi-layered Ti3C2Tx. Repeat centrifugation and addition of deionized water for ultrasonication to adjust the pH of the reaction solution to 5, then add 5 ml of ethanol, place it in a high-power ultrasonic machine (750 W) and ultrasonicate for 10 min, and centrifuge at 10000 rpm for 10 min to obtain monolayer MXene material.

[0034] The polyethyleneimine used in this application has a molecular weight Mn = 10000; the MAX-Ti3AlC2 has a specification of 200 mesh and is purchased from Jilin Yiyi Technology Co., Ltd.; chitosan oligosaccharide is produced by Zhejiang Jinke Pharmaceutical Co., Ltd., with a purity of 99% and a number-average molecular weight of 2750; chitosan is produced by Zhejiang Jinke Pharmaceutical Co., Ltd., with a purity of 99% and an average molecular weight of 25000 daltons.

[0035] Use a rectangular mold and use an infrared tablet press to press the conductive microspheres into tablets to make samples with a cross-sectional area of 6 cm 2 and a length of 3 cm. Use a four-probe surface impedance analyzer to measure the surface resistance value of the conductive microspheres, and then calculate the conductivity; use a Malvern dynamic light scattering instrument to measure the particle size distribution and calculate the average particle size and coefficient of variation C.V. The test results are shown in Table 1.

[0036] Table 1

[0037] It can be seen from Table 1 that the coefficient of variation of the particle size of the polymer conductive microspheres prepared in Examples 4, 5, and 6 is less than 2.4%, and the conductivity is greater than 4.7×10 3 S / m, showing excellent conductivity.

[0038] For Comparative Example 1, which is a comparative example with AIBN as the initiator added, it can be seen from the data in Table 1 that the conductivity is 9.5×10 2 S / m, the average particle size is 8.61 μm, and the conductivity performance is poor.

[0039] Comparative Examples 2-5 are comparative examples different from Example 5. The difference is that the grafting rates of 4-(diethylamino)salicylaldehyde and Intermediate 1 on chitosan oligosaccharide are different. It can be seen from the data in Table 1 that the increase or decrease in the grafting of the two grafting compounds has a greater impact on the coefficient of variation of the microspheres. The grafted 4-(diethylamino)salicylaldehyde can improve the solubility of the macromolecular initiator in organic solvents. When the grafting amount is small, the solubility of the macromolecular initiator is poor, resulting in a poor effect of the polymerization reaction and poor conductivity performance of the prepared conductive microspheres.

[0040] Comparative Example 6 is a comparative example different from Example 5. The difference is that the intermediate 1 prepared in step S1 of the preparation process of the macromolecular initiator is replaced with 2-bromoisobutyryl bromide. It can be seen from the data in Table 1 that the conductivity is 3.1×10 3 S / m, the average particle size is 4.57 μm, and the coefficient of variation of the microspheres is relatively large.

[0041] Comparative Example 7 is a comparative example different from Example 5. The difference is that 4-(diethylamino)salicylaldehyde is not added during the preparation process of the macromolecular initiator. It can be seen from the data in Table 1 that the conductivity is 2.9×10 3 S / m, and the average particle size is 5.24 μm.

[0042] Comparative Example 8 is a comparative example different from Example 5. The difference is that 4-(diethylamino)salicylaldehyde in step S2 of the preparation process of the macromolecular initiator is replaced with salicylaldehyde. It can be seen from the data in Table 1 that the conductivity is 3.3×10 3 S / m, the average particle size is 4.01 μm, and the coefficient of variation of the microspheres is relatively large.

[0043] Comparative Example 9 is a comparative example different from Example 5. The difference is that 2-bromoisobutyryl bromide in step S2 of the preparation process of the macromolecular initiator is replaced with dichloroacetyl chloride. It can be seen from the data in Table 1 that the conductivity is 3.7×10 3 S / m, and the average particle size is 4.63 μm.

[0044] Comparative Examples 10 and 11 are comparative examples different from Example 5. The difference is that chitosan oligosaccharide in the preparation process of the macromolecular initiator is replaced with chitosan. It can be seen from the data in Table 1 that the particle size distribution uniformity is not as good as that of this application, and the electrical conductivity is also not as good as that of this application.

[0045] Comparative Example 12 is a conductive microsphere with a surface protrusion structure prepared by using the raw material composition, ratio and method of Example 1 of the Chinese invention patent with the publication number CN115109277A. It can be seen from the data in Table 1 that the conductivity is 2.2×10 3 S / m, and the electrical conductivity is poor.

[0046] Table 2 shows the conductivity, average particle size and coefficient of variation of the examples obtained by changing the addition amount of the macromolecular initiator on the basis of Example 5.

[0047] Table 2

[0048] It can be seen from the data in Table 2 that highly conductive microspheres with different particle sizes can be prepared by controlling the addition amount of the initiator.

[0049] As described above, it is only the preferred embodiment of the present invention and is not used to limit the present invention. However, for those of ordinary skill in the art, within the scope of the technical solution of the present invention, any slight changes, modifications, and equivalent variations made by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any changes, modifications, and equivalent variations made to the above embodiments based on the essential technology of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A polymer conductive microsphere, characterized in that, It includes raw materials in the following parts by weight: Styrene: 30 - 50 parts, divinylbenzene: 20 - 40 parts, macroinitiator: 0.5 - 1.5 parts, stabilizer: 2 - 6 parts, foaming agent: 4 - 6 parts, Mxene material: 10 - 12 parts, deionized water: 80 parts, toluene: 200 parts; The macroinitiator is prepared by the following method: S1: Add dichloromethane, epichlorohydrin, and triethylamine into a reactor, stir, slowly drop 2 - bromoisobutyryl bromide in an ice bath, react for 2 - 4 h, then raise the temperature to room temperature and continue to react for 8 - 10 h, and perform post - treatment to obtain intermediate 1; S2: Chitosan reacts with 4 - (diethylamino)salicylaldehyde under the action of the catalyst glacial acetic acid to obtain intermediate 2; S3: Add pyridine, intermediate 1, and intermediate 2 into the reactor in sequence, stir and mix evenly, raise the temperature to 80 - 105 °C, add sodium hydride, react for 4 - 6 h, and perform post - treatment to obtain the macroinitiator.

2. The polymer conductive microsphere according to claim 1, characterized in that, In step S1, the feeding mass ratio of dichloromethane, epichlorohydrin, and 2 - bromoisobutyryl bromide is 30:(6 - 8):(8 - 10).

3. The polymer conductive microsphere according to claim 1, characterized in that, In step S2, the feeding mass ratio of chitosan and 4 - (diethylamino)salicylaldehyde is 10:(3 - 4.5).

4. A polymer conductive microsphere according to claim 1, characterized in that, In step S3, the feeding mass ratio of intermediate 1 and intermediate 2 is (3 - 4):

10.

5. A polymer conductive microsphere according to claim 1, characterized in that, The stabilizer is one of polyethyleneimine and polyvinylpyrrolidone.

6. The polymer conductive microsphere according to claim 1, characterized in that, The foaming agent is one of magnesium carbonate, sodium bicarbonate, and sodium dodecyl sulfate.

7. A method for preparing the polymer conductive microspheres according to any one of claims 1-6, characterized in that, It includes the following steps: S1: Weigh by parts by weight: styrene: 30 - 50 parts, divinylbenzene: 20 - 40 parts, macroinitiator: 0.5 - 1.5 parts, stabilizer: 2 - 6 parts, foaming agent: 4 - 6 parts, Mxene material: 10 - 12 parts, deionized water: 80 parts, toluene: 200 parts; S2: Add toluene, styrene, divinylbenzene, stabilizer, macroinitiator, and foaming agent into a reactor, introduce nitrogen, perform ultrasonic dispersion, raise the temperature to 80 - 100 °C, and react for 10 - 16 h to obtain a mixed solution A; S3: Add the Mxene material into deionized water, perform ultrasonic mixing to obtain a mixed solution B, slowly add the mixed solution A into the mixed solution B, raise the temperature to 100 - 120 °C, react for 16 - 20 h, and perform post - treatment to obtain polymer conductive microspheres.

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