Replaceable polyaniline filler for conductive coating and preparation method thereof

Abstract

The invention relates to a replaceable polyaniline filler for a conductive coating and a preparation method thereof, and the preparation method comprises the following preparation steps: S1, acidifying toluene diisocynate: mixing a toluene diisocynate kettle bottom material with acid to obtain an acidified toluene diisocynate system; s2, synthesizing a conductive polymer: slowly dropwise adding an oxidizing agent into the acidified toluene diisocyanate system in the step S1, and reacting to obtain conductive polymer slurry; and S3, cleaning, drying and grinding the conductive polymer slurry obtained in the step S2 to obtain conductive polymer powder, namely the replaceable polyaniline filler for the conductive coating. Compared with the prior art, the preparation method provided by the invention has the advantages that the process is simple, the raw materials are easy to obtain, the waste generated by synthesizing TDI in the industry can be treated in a green and environment-friendly manner, the waste is turned into wealth, and the conductivity of the synthesized polymer is not weaker than that of polyaniline.

Description

Technical Field

[0001] The invention relates to the technical field of conductive materials, in particular to a replaceable polyaniline filler for conductive coatings and a preparation method thereof. Background Art

[0002] As a conductive polymer, polyaniline (PANI) is widely used in shielding materials, conductive materials, optoelectronic display materials and other fields, and provides a possibility for the development of new environmentally friendly excellent coatings on light alloy surfaces. Polyaniline has excellent environmental stability, simple synthesis method, easy raw materials and unique doping mechanism. Therefore, researchers combine it with traditional organic resins to obtain polyaniline anti-corrosion coatings with excellent corrosion resistance, thereby achieving multiple protection for light alloy substrates.

[0003] However, due to the strong rigidity of the polyaniline molecular chain skeleton and the strong interaction between molecules, its solubility is poor, so the prepared coating is prone to problems such as poor solubility and easy agglomeration, and its practical application is relatively limited. Therefore, it is very necessary to find a material that can replace conductive polyaniline. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a replaceable polyaniline filler for conductive coatings and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a method for preparing a replaceable polyaniline filler for conductive coatings, comprising the following steps:

[0007] S1, acidified toluene diisocyanate (TDI): mixing toluene diisocyanate kettle bottom material with acid to obtain an acidified toluene diisocyanate system;

[0008] S2, synthesis of conductive polymer: slowly adding an oxidant to the acidified toluene diisocyanate system in step S1, and reacting to obtain conductive polymer slurry;

[0009] S3, washing, drying and grinding the conductive polymer slurry obtained in step S2 to obtain conductive polymer powder, which is a substitute for polyaniline filler for conductive coatings.

[0010] In some specific embodiments, in step S1, the toluene diisocyanate kettle bottoms are derived from tar waste generated by industrial synthesis of toluene diisocyanate using the phosgene method.

[0011] In some specific embodiments, in step S1, the acid is selected from any one or more of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0012] Preferably, the acid is selected from any one or more of 1 mol / L hydrochloric acid, 1 mol / L sulfuric acid, and 1 mol / L phosphoric acid.

[0013] In some specific embodiments, in step S1, the molar ratio of the toluene diisocyanate kettle bottoms to the acid is 1:1.

[0014] In some specific embodiments, in step S2, the temperature when the oxidant is added dropwise is 45°C to 65°C, and the oxidant is added dropwise for 3 to 4 hours.

[0015] In some specific embodiments, in step S2, the oxidant is a hydrogen peroxide solution with a mass fraction of 15%.

[0016] In some specific embodiments, in step S2, the mass ratio of the oxidant to the acidified toluene diisocyanate system is 2:11.

[0017] In some specific embodiments, in step S2, the reaction temperature is increased from the temperature when the oxidant is added to 90°C, the heating rate is 30°C to 40°C / h, and the temperature is kept for 1 hour.

[0018] In some specific embodiments, in step S3, the cleaning is to use deionized water to clean the conductive polymer slurry until it becomes neutral.

[0019] The second technical solution of the present invention is to provide a replaceable polyaniline filler for conductive coatings, which is obtained based on the preparation method described in one of the above technical solutions.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The preparation method provided by the present invention has a simple process, readily available raw materials, and can be used to treat waste generated by industrial synthesis of TDI in an environmentally friendly manner.

[0022] (2) The raw materials of the present invention are turned into valuable materials, and the conductivity of the synthesized polymer is not inferior to that of polyaniline, and can replace polyaniline filler. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Electron micrographs of the polymer fillers prepared in Examples 1 to 3 (B, C, D) and Comparative Example 1 (A). DETAILED DESCRIPTION

[0024] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0025] In the following examples and comparative examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0026] Embodiment 1:

[0027] A method for preparing a replaceable polyaniline filler for conductive coatings comprises the following steps:

[0028] (1) Acidified TDI kettle bottom material

[0029] An equal amount of TDI kettle bottoms was mixed and stirred with 1 mol / L hydrochloric acid to obtain acidified TDI kettle bottoms, which was then placed in a four-necked flask for later use.

[0030] (2) Synthesis of Conductive Polymers

[0031] At 50°C, a 15% by mass hydrogen peroxide solution was slowly added dropwise to a solution containing acidified TDI kettle bottom material, and the dropping speed was controlled. The mass ratio of the peroxide solution to the acidified toluene diisocyanate system was 2:11, so that the dropping time of the hydrogen peroxide solution was 3.5 hours. After the hydrogen peroxide solution was added dropwise, the temperature was slowly increased to 90°C at a heating rate of 35°C / h and kept for 1 hour, cooled, and discharged to obtain a conductive polymer slurry.

[0032] (3) Preparation of Conductive Polymer Powder

[0033] The prepared conductive polymer slurry is washed with deionized water until it becomes neutral, dried, and ground to obtain conductive polymer powder.

[0034] Embodiment 2:

[0035] A method for preparing a replaceable polyaniline filler for conductive coatings.

[0036] (1) Acidified TDI kettle bottom material

[0037] An equal amount of TDI kettle bottoms was mixed and stirred with 1 mol / L sulfuric acid to prepare acidified TDI kettle bottoms, which was then placed in a four-necked flask for later use.

[0038] (2) Synthesis of Conductive Polymers

[0039] At 50°C, a 15% by mass hydrogen peroxide solution was slowly added dropwise to a solution containing acidified TDI kettle bottom material, and the dropping speed was controlled. The mass ratio of the peroxide solution to the acidified toluene diisocyanate system was 2:11, so that the dropping time of the hydrogen peroxide solution was 3.5 hours. After the hydrogen peroxide solution was added dropwise, the temperature was slowly increased to 90°C at a heating rate of 35°C / h and kept for 1 hour, cooled, and discharged to obtain a conductive polymer slurry.

[0040] (3) Preparation of Conductive Polymer Powder

[0041] The prepared conductive polymer slurry is washed with deionized water until it becomes neutral, dried, and ground to obtain conductive polymer powder.

[0042] Embodiment 3:

[0043] A method for preparing a replaceable polyaniline filler for conductive coatings.

[0044] (1) Acidified TDI kettle bottom material

[0045] An equal amount of TDI kettle bottoms was mixed and stirred with 1 mol / L phosphoric acid to prepare acidified TDI kettle bottoms, which was then placed in a four-necked flask for later use.

[0046] (2) Synthesis of Conductive Polymers

[0047] At 50°C, a 15% by mass hydrogen peroxide solution was slowly added dropwise to a solution containing acidified TDI kettle bottom material, and the dropping speed was controlled. The mass ratio of the peroxide solution to the acidified toluene diisocyanate system was 2:11, so that the dropping time of the hydrogen peroxide solution was 3.5 hours. After the hydrogen peroxide solution was added dropwise, the temperature was slowly increased to 90°C at a heating rate of 35°C / h and kept for 1 hour, cooled, and discharged to obtain a conductive polymer slurry.

[0048] (3) Preparation of Conductive Polymer Powder

[0049] The prepared conductive polymer slurry is washed with deionized water until it becomes neutral, dried, and ground to obtain conductive polymer powder.

[0050] Comparative Example 1:

[0051] This comparative example provides a method for preparing a polyaniline filler, comprising the following steps:

[0052] (1) Acidification of aniline

[0053] An equimolar amount of aniline and 1 mol / L hydrochloric acid were mixed and stirred to prepare an acidified aniline solution, which was placed in a four-necked flask for later use.

[0054] (2) Synthesis of polyaniline

[0055] In an ice water bath (0-4°C), hydrogen peroxide was slowly added dropwise to the acidified aniline solution. The dropping speed was controlled so that the mass ratio of the peroxide solution to the acidified aniline system was 2:11, and the dropping time of the hydrogen peroxide solution was 3.5 hours. After the oxidant was added dropwise, the reaction was continued for 12 hours to obtain a polyaniline slurry.

[0056] (3) Preparation of polyaniline powder

[0057] The prepared polyaniline slurry is washed with deionized water until it becomes neutral, dried, and ground to obtain polyaniline powder.

[0058] The polymer powders prepared in Test Examples 1 to 3 were compared with the polymer powder prepared in Comparative Example 1. The results are shown in Table 1.

[0059] Table 1

[0060] Test items Comparative Example Example 1 Example 2 Example 3 Test Method Conductivity(s / cm) 1.95E-04 2.36E-05 1.69E-04 4.54E-05 Four-probe test

[0061] It can be seen from Table 1 that the conductivity of the polymer obtained by the preparation method of the present invention is not inferior to that of polyaniline. From the perspective of conductivity, it can completely replace polyaniline.

[0062] Depend on Figure 1 It can be seen that the polyaniline powder (A) is severely agglomerated, while the polymer powders (B, C, D) obtained by the preparation method of the present invention do not have obvious agglomeration phenomenon. From the perspective of dispersibility, the polymer powders obtained by the preparation method of the present invention are superior to the polyaniline powder.

[0063] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a replaceable polyaniline filler for conductive coatings, characterized in that: The steps include: S1, acidified toluene diisocyanate: mixing toluene diisocyanate kettle bottom material with acid to obtain an acidified toluene diisocyanate system; S2, synthesis of conductive polymer: slowly adding an oxidant to the acidified toluene diisocyanate system in step S1, and reacting to obtain conductive polymer slurry; S3, washing, drying and grinding the conductive polymer slurry obtained in step S2 to obtain conductive polymer powder, which is a substitute for polyaniline filler for conductive coatings.

2. The preparation method according to claim 1, characterized in that: In step S1, the toluene diisocyanate kettle bottoms are derived from tar waste generated by industrial synthesis of toluene diisocyanate using the phosgene method.

3. The preparation method according to claim 1, characterized in that: In step S1, the acid is selected from any one or more of hydrochloric acid, sulfuric acid, and phosphoric acid.

4. The preparation method according to claim 3, characterized in that: The molar ratio of the toluene diisocyanate kettle bottom material to the acid is 1:

1.

5. The preparation method according to claim 1, characterized in that: In step S2, the temperature when the oxidant is added dropwise is 45°C to 65°C, and the addition time of the oxidant is 3 to 4 hours.

6. The preparation method according to claim 1, characterized in that: In step S2, the oxidant is a hydrogen peroxide solution with a mass fraction of 15%.

7. The preparation method according to claim 6, characterized in that: In step S2, the mass ratio of the oxidant to the acidified toluene diisocyanate system is 2:

11.

8. The preparation method according to claim 1, characterized in that: In step S2, the reaction temperature is raised from the temperature when the oxidant is added to 90°C at a rate of 30°C to 40°C / h, and the temperature is kept for 1 hour.

9. The preparation method according to claim 1, characterized in that: In step S3, the cleaning is to use deionized water to clean the conductive polymer slurry until it becomes neutral.

10. A replaceable polyaniline filler for conductive coating, characterized in that: The method is based on any one of claims 1 to 9.

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