Preparation method and application of carbon nanotube modified acrylic resin coating

Abstract

The invention relates to the technical field of coating materials, and discloses a carbon nano tube modified acrylic resin coating, in the synthesis process, sulfydryl modified carbon nano tubes and dibenzoyl peroxide form an oxidation-reduction initiation system to obtain sulfydryl free radicals and benzoyl free radicals, and the sulfydryl free radicals and the benzoyl free radicals are mixed to form the carbon nano tube modified acrylic resin coating. The generated hydrogen protons attack alkenyl and sulfydryl on acrylic acid, methyl methacrylate, butyl acrylate and acrylamide to initiate polymerization, and the carbon nanotubes are uniformly dispersed in an acrylic resin structure after being grafted with the acrylic resin due to excellent thermodynamic stability, corrosion resistance and chemical stability, so that the carbon nanotubes have good thermal stability, corrosion resistance and chemical stability. An interlaced network structure is formed in the acrylic resin, the size of gaps in the coating is reduced, the compactness of the coating is improved to a great extent, corrosive liquid is prevented from invading the interior, and the problems of poor thermodynamic stability and poor chemical corrosion resistance of the acrylic resin are effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of coating materials, in particular to a preparation method and application of a carbon nanotube modified acrylic resin coating. Background Art

[0002] Coatings are currently the most effective, quickest and most widely used means of metal protection. They are widely used in production and life and play an important protective role for metals. Organic coatings are generally composed of resins, solvents, fillers and various additives. Among them, water-based coatings are an important component. Because water is used as the dispersion medium and the organic solvent content is relatively low, it is a non-toxic, pollution-free and environmentally friendly coating. It occupies an important position in modern coatings. At the same time, because it is an environmentally friendly material, it has important research and practical value.

[0003] In the modern coatings industry, acrylic resin, as a common film-forming agent, has the advantages of strong adhesion and simple production process. At the same time, it is cheap, highly transparent and corrosion-resistant. This series of advantages makes acrylic resin have great research prospects. However, due to its low hardness, poor solvent resistance and heat resistance, its application is greatly limited. Nanomaterials can be effectively modified by adding them to traditional coatings due to their unique nano effect. Carbon nanotubes are considered to be an ideal coating modification material due to their good mechanical properties and excellent electrical conductivity, thermal conductivity, corrosion resistance and chemical stability. They can greatly improve the chemical corrosion resistance and thermal stability of coatings. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method for preparing and applying a carbon nanotube-modified acrylic resin coating, which solves the problems of poor thermal stability and poor chemical corrosion resistance of acrylic resin.

[0005] To achieve the above object, the present invention provides the following technical solution: a carbon nanotube-modified acrylic resin coating, wherein the preparation method of the carbon nanotube-modified acrylic resin coating comprises the following steps: (1) adding carboxylated carbon nanotubes to thionyl chloride and N,N-dimethylformamide to produce an acyl chloride reaction, followed by filtration, washing, and drying to obtain acyl chloride carbon nanotubes; (2) adding acyl chloride carbon nanotubes to dimethyl sulfoxide, and then adding 2,3-dimercapto-1-propanol, stirring and mixing, causing a substitution reaction, filtering, washing, and drying to obtain thiol-modified carbon nanotubes; (3) adding mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate and acrylamide to N,N-dimethylformamide, filling with nitrogen, adding dibenzoyl peroxide in the nitrogen atmosphere, stirring and mixing, causing polymerization reaction, and after the polymerization reaction is completed, filtering and washing to obtain carbon nanotube-modified acrylic resin; (4) Adding the carbon nanotube-modified acrylic resin to a deionized water solvent, and then adding a silicon-free defoaming agent and a leveling agent polydimethylsiloxane of an alkyl vinyl ether graft copolymer, ultrasonically dispersing, and filtering to obtain a carbon nanotube-modified acrylic resin coating.

[0006] Preferably, in step (2), the mass ratio of the acyl chloride carbon nanotubes to 3-mercapto-1-propanol is 12-20:100.

[0007] Preferably, the temperature of the substitution reaction in step (2) is 75-90° C., and the time of the substitution reaction is 24-30 h.

[0008] Preferably, in step (3), the mass ratio of mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.2-1.8:100:150-550:250-400:30-60:0.8-1.5.

[0009] Preferably, the polymerization reaction temperature in step (3) is 60-80° C., and the polymerization reaction time is 3-6 h.

[0010] Preferably, in step (4), the mass ratio of carbon nanotube-modified acrylic resin, alkyl vinyl ether graft copolymer and polydimethylsiloxane is 100:0.5-1.2:0.6-1.5.

[0011] Preferably, the carbon nanotube-modified acrylic resin coating in step (4) is used in the field of coating materials.

[0012] Compared with the prior art, the present invention has the following chemical mechanisms and beneficial technical effects: The carbon nanotube modified acrylic resin coating comprises the following steps: during the synthesis process, hydroxyl groups on carboxylated carbon nanotubes react with thionyl chloride to obtain chlorinated carbon nanotubes, and chlorinated carboxylated carbon nanotubes react with hydroxyl groups on 2,3-dimercapto-1-propanol to obtain thiol-modified carbon nanotubes; thiol groups on the surface of the carbon nanotubes and added dibenzoyl peroxide form an oxidation-reduction initiation system, and after reacting with dibenzoyl peroxide, thiol free radicals and benzoyl free radicals are obtained; the generated hydrogen protons attack the alkenyl groups on acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, and the thiol groups initiate polymerization to cause in-situ polymerization to obtain carbon nanotube modified acrylic resin; and then corresponding auxiliary agents are added to obtain carbon nanotube modified acrylic resin coating.

[0013] The carbon nanotube modified acrylic resin coating has a large number of hydroxyl groups and carboxyl groups on the surface of the carboxylated carbon nanotubes, so that the carbon nanotubes can be better dispersed in the solution. The carbon nanotubes have a large specific surface area and can better provide corresponding active sites for the polymerization of acrylic substances after being modified with thiol groups. At the same time, due to the excellent thermodynamic stability, corrosion resistance and chemical stability of the carbon nanotubes, after being grafted with the acrylic resin, the carbon nanotubes are uniformly dispersed in the acrylic resin structure, forming an interwoven network structure inside the acrylic resin, reducing the void size inside the coating, greatly increasing the density of the coating, preventing the corrosion liquid from invading the interior, and effectively reducing the problems of poor thermodynamic stability and poor chemical corrosion resistance of the acrylic resin. DETAILED DESCRIPTION

[0014] To achieve the above object, the present invention provides the following specific implementation methods and examples: A carbon nanotube modified acrylic resin coating, the preparation method of which comprises the following steps: (1) Add N,N-dimethylformamide to a beaker, then add carboxylated carbon nanotubes and dichlorothionyl, stir, and cause an acyl chloride reaction. After the reaction is completed, filter, wash with dichloromethane and ethanol, and dry to obtain acyl chloride carbon nanotubes; (2) Add dimethyl sulfoxide to a beaker, and then add acyl chloride carbon nanotubes and 2,3-dimercapto-1-propanol in a mass ratio of 12-20:100, stir and mix, and a substitution reaction occurs. The temperature of the substitution reaction is 75-90°C, and the time of the substitution reaction is 24-30 hours. After the reaction is completed, filter, wash, and dry to obtain thiol-modified carbon nanotubes; (3) Add N,N-dimethylformamide to a flask, then add mercapto-modified carbon nanotubes and acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, fill with nitrogen, add dibenzoyl peroxide in a nitrogen atmosphere, the mass ratio of the added mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.2-1.8:100:150-550:250-400:30-60:0.8-1.5, stir and mix, and a polymerization reaction occurs. The polymerization reaction temperature is 60-80°C, and the polymerization reaction time is 3-6h. After the polymerization reaction is completed, filter and wash to obtain a carbon nanotube-modified acrylic resin; (4) Add deionized water to a beaker, and then add carbon nanotube-modified acrylic resin, alkyl vinyl ether graft copolymer, silicon-free defoaming agent and leveling agent polydimethylsiloxane in a mass ratio of 100:0.5-1.2:0.6-1.5, ultrasonically disperse, and filter to obtain a carbon nanotube-modified acrylic resin coating for use in the field of coating materials. Example 1

[0015] (1) Add N,N-dimethylformamide to a beaker, then add carboxylated carbon nanotubes and dichlorothionyl, stir, and cause an acyl chloride reaction. After the reaction is completed, filter, wash with dichloromethane and ethanol, and dry to obtain acyl chloride carbon nanotubes; (2) Add dimethyl sulfoxide to a beaker, then add acyl chloride carbon nanotubes and 2,3-dimercapto-1-propanol in a mass ratio of 12:100, stir and mix, and a substitution reaction occurs. The temperature of the substitution reaction is 75°C, and the substitution reaction time is 24 hours. After the reaction is completed, filter, wash, and dry to obtain thiol-modified carbon nanotubes; (3) Add N,N-dimethylformamide to a flask, then add mercapto-modified carbon nanotubes and acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, fill with nitrogen, add dibenzoyl peroxide in a nitrogen atmosphere, the mass ratio of the added mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.2:100:150:250:30:0.8, stir and mix, and a polymerization reaction occurs. The polymerization reaction temperature is 60°C and the polymerization reaction time is 3 hours. After the polymerization reaction is completed, filter and wash to obtain a carbon nanotube-modified acrylic resin; (4) Deionized water was added to a beaker, and then a carbon nanotube-modified acrylic resin, an alkyl vinyl ether graft copolymer, a silicon-free defoaming agent, and a leveling agent polydimethylsiloxane were added in a mass ratio of 100:0.5:0.6, and the mixture was dispersed by ultrasonic and filtered to obtain a carbon nanotube-modified acrylic resin coating for use in the field of coating materials. Example 2

[0016] (1) Add N,N-dimethylformamide to a beaker, then add carboxylated carbon nanotubes and dichlorothionyl, stir, and cause an acyl chloride reaction. After the reaction is completed, filter, wash with dichloromethane and ethanol, and dry to obtain acyl chloride carbon nanotubes; (2) Add dimethyl sulfoxide to a beaker, then add acyl chloride carbon nanotubes and 2,3-dimercapto-1-propanol in a mass ratio of 14:100, stir and mix, and a substitution reaction occurs. The temperature of the substitution reaction is 80°C, and the time of the substitution reaction is 25 hours. After the reaction is completed, filter, wash, and dry to obtain thiol-modified carbon nanotubes; (3) Add N,N-dimethylformamide to a flask, then add mercapto-modified carbon nanotubes and acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, fill with nitrogen, add dibenzoyl peroxide in a nitrogen atmosphere, the mass ratio of the added mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.4:100:300:320:40:0.9, stir and mix, and a polymerization reaction occurs. The polymerization reaction temperature is 65°C and the polymerization reaction time is 4 hours. After the polymerization reaction is completed, filter and wash to obtain a carbon nanotube-modified acrylic resin; (4) Deionized water was added to a beaker, and then a carbon nanotube-modified acrylic resin, an alkyl vinyl ether graft copolymer, a silicon-free defoaming agent, and a leveling agent polydimethylsiloxane were added in a mass ratio of 100:0.8:0.9, and the mixture was dispersed by ultrasonic and filtered to obtain a carbon nanotube-modified acrylic resin coating for use in the field of coating materials. Example 3

[0017] (1) Add N,N-dimethylformamide to a beaker, then add carboxylated carbon nanotubes and dichlorothionyl, stir, and cause an acyl chloride reaction. After the reaction is completed, filter, wash with dichloromethane and ethanol, and dry to obtain acyl chloride carbon nanotubes; (2) Add dimethyl sulfoxide to a beaker, then add acyl chloride carbon nanotubes and 2,3-dimercapto-1-propanol in a mass ratio of 15:100, stir and mix, and a substitution reaction occurs. The temperature of the substitution reaction is 80°C, and the time of the substitution reaction is 26 hours. After the reaction is completed, filter, wash, and dry to obtain thiol-modified carbon nanotubes; (3) Add N,N-dimethylformamide to a flask, then add mercapto-modified carbon nanotubes and acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, fill with nitrogen, add dibenzoyl peroxide in a nitrogen atmosphere, the mass ratio of the added mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.5:100:450:350:50:1.2, stir and mix, and a polymerization reaction occurs. The polymerization reaction temperature is 70°C and the polymerization reaction time is 5 hours. After the polymerization reaction is completed, filter and wash to obtain a carbon nanotube-modified acrylic resin; (4) Deionized water is added to a beaker, and then a carbon nanotube-modified acrylic resin, an alkyl vinyl ether graft copolymer, a silicon-free defoaming agent, and a leveling agent polydimethylsiloxane are added in a mass ratio of 100:0.9:1.2, and the mixture is dispersed by ultrasonication and filtered to obtain a carbon nanotube-modified acrylic resin coating for use in the field of coating materials. Example 4

[0018] (1) Add N,N-dimethylformamide to a beaker, then add carboxylated carbon nanotubes and dichlorothionyl, stir, and cause an acyl chloride reaction. After the reaction is completed, filter, wash with dichloromethane and ethanol, and dry to obtain acyl chloride carbon nanotubes; (2) Add dimethyl sulfoxide to a beaker, then add acyl chloride carbon nanotubes and 2,3-dimercapto-1-propanol in a mass ratio of 18:100, stir and mix, and a substitution reaction occurs. The temperature of the substitution reaction is 85°C, and the substitution reaction time is 28 hours. After the reaction is completed, filter, wash, and dry to obtain thiol-modified carbon nanotubes; (3) Add N,N-dimethylformamide to a flask, then add mercapto-modified carbon nanotubes and acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, fill with nitrogen, add dibenzoyl peroxide in a nitrogen atmosphere, the mass ratio of the added mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.7:100:500:380:55:1.4, stir and mix, and a polymerization reaction occurs. The polymerization reaction temperature is 75°C and the polymerization reaction time is 5 hours. After the polymerization reaction is completed, filter and wash to obtain a carbon nanotube-modified acrylic resin; (4) Deionized water is added to a beaker, and then a carbon nanotube-modified acrylic resin, an alkyl vinyl ether graft copolymer, a silicon-free defoaming agent, and a leveling agent polydimethylsiloxane are added in a mass ratio of 100:1.1:1.4, and the mixture is dispersed by ultrasonication and filtered through a filter to obtain a carbon nanotube-modified acrylic resin coating for use in the field of coating materials. Example 5

[0019] (1) Add N,N-dimethylformamide to a beaker, then add carboxylated carbon nanotubes and dichlorothionyl, stir, and cause an acyl chloride reaction. After the reaction is completed, filter, wash with dichloromethane and ethanol, and dry to obtain acyl chloride carbon nanotubes; (2) Add dimethyl sulfoxide to a beaker, then add acyl chloride carbon nanotubes and 2,3-dimercapto-1-propanol in a mass ratio of 20:100, stir and mix, and a substitution reaction occurs. The temperature of the substitution reaction is 90°C, and the time of the substitution reaction is 30 hours. After the reaction is completed, filter, wash, and dry to obtain thiol-modified carbon nanotubes; (3) Add N,N-dimethylformamide to a flask, then add mercapto-modified carbon nanotubes and acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, fill with nitrogen, add dibenzoyl peroxide in a nitrogen atmosphere, the mass ratio of the added mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.8:100:550:400:60:1.5, stir and mix, and a polymerization reaction occurs. The polymerization reaction temperature is 80°C and the polymerization reaction time is 6 hours. After the polymerization reaction is completed, filter and wash to obtain a carbon nanotube-modified acrylic resin; (4) Deionized water is added to a beaker, and then a carbon nanotube-modified acrylic resin, an alkyl vinyl ether graft copolymer, a silicon-free defoaming agent, and a leveling agent polydimethylsiloxane are added in a mass ratio of 100:1.2:1.5, and the mixture is dispersed by ultrasonication and filtered through a filter to obtain a carbon nanotube-modified acrylic resin coating for use in the field of coating materials.

[0020] Comparative Example 1 (1) Add N,N-dimethylformamide to a beaker, then add carboxylated carbon nanotubes and dichlorothionyl, stir, and cause an acyl chloride reaction. After the reaction is completed, filter, wash with dichloromethane and ethanol, and dry to obtain acyl chloride carbon nanotubes; (2) Add dimethyl sulfoxide to a beaker, then add acyl chloride carbon nanotubes and 2,3-dimercapto-1-propanol in a mass ratio of 8:100, stir and mix, and a substitution reaction occurs. The temperature of the substitution reaction is 80°C, and the time of the substitution reaction is 28 hours. After the reaction is completed, filter, wash, and dry to obtain thiol-modified carbon nanotubes; (3) Add N,N-dimethylformamide to a flask, then add mercapto-modified carbon nanotubes and acrylic acid, methyl methacrylate, butyl acrylate and acrylamide, fill with nitrogen, add dibenzoyl peroxide in a nitrogen atmosphere, the mass ratio of the added mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 0.9:100:120:220:25:0.5, stir and mix, and a polymerization reaction occurs. The polymerization reaction temperature is 70°C and the polymerization reaction time is 5 hours. After the polymerization reaction is completed, filter and wash to obtain a carbon nanotube-modified acrylic resin; (4) Deionized water is added to a beaker, and then a carbon nanotube-modified acrylic resin, an alkyl vinyl ether graft copolymer, a silicon-free defoaming agent, and a leveling agent polydimethylsiloxane are added in a mass ratio of 100:0.4:0.5, and the mixture is dispersed by ultrasonication and filtered through a filter to obtain a carbon nanotube-modified acrylic resin coating for use in the field of coating materials.

[0021] The carbon nanotube-modified acrylic resin coatings in the examples and comparative examples were dried and cured in an oven, and thermal stability performance of the samples was analyzed using a TGA / SDTA851E thermal analyzer, with a scanning range of 40-600°C and a heating rate of 10°C / min during the scanning process, and the corresponding complete decomposition temperature was tested.

[0022]

[0023] The carbon nanotube-modified acrylic resin coating in the embodiment and the comparative example was uniformly coated on a tinplate substrate, and after surface drying, it was transferred to an oven for drying and curing to obtain a corresponding coating sample, which was placed in a 10% HCl solution for one week to observe the corresponding coating changes.

[0024]

Claims

1. A carbon nanotube modified acrylic resin coating, characterized in that: The preparation method of the carbon nanotube modified acrylic resin coating comprises the following steps: (1) adding carboxylated carbon nanotubes to thionyl chloride and N,N-dimethylformamide to produce an acyl chloride reaction, followed by filtration, washing, and drying to obtain acyl chloride carbon nanotubes; (2) adding acyl chloride carbon nanotubes to dimethyl sulfoxide, and then adding 2,3-dimercapto-1-propanol, stirring and mixing, causing a substitution reaction, filtering, washing, and drying to obtain thiol-modified carbon nanotubes; (3) adding mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate and acrylamide to N,N-dimethylformamide, filling with nitrogen, adding dibenzoyl peroxide in the nitrogen atmosphere, stirring and mixing, causing polymerization reaction, and after the polymerization reaction is completed, filtering and washing to obtain carbon nanotube-modified acrylic resin; (4) Adding the carbon nanotube-modified acrylic resin to a deionized water solvent, and then adding a silicon-free defoaming agent and a leveling agent polydimethylsiloxane of an alkyl vinyl ether graft copolymer, ultrasonically dispersing, and filtering to obtain a carbon nanotube-modified acrylic resin coating.

2. The carbon nanotube-modified acrylic resin coating according to claim 1, characterized in that: In the step (2), the mass ratio of the acyl chloride carbon nanotubes to 3-mercapto-1-propanol is 12-20:

100.

3. The carbon nanotube-modified acrylic resin coating according to claim 1, characterized in that: The temperature of the substitution reaction in step (2) is 75-90° C., and the time of the substitution reaction is 24-30 hours.

4. The carbon nanotube-modified acrylic resin coating according to claim 1, characterized in that: In the step (3), the mass ratio of mercapto-modified carbon nanotubes, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide and dibenzoyl peroxide is 1.2-1.8:100:150-550:250-400:30-60:0.8-1.

5.

5. The carbon nanotube-modified acrylic resin coating according to claim 1, characterized in that: The polymerization reaction temperature in step (3) is 60-80° C., and the polymerization reaction time is 3-6 hours.

6. The carbon nanotube-modified acrylic resin coating according to claim 1, characterized in that: In the step (4), the mass ratio of carbon nanotube modified acrylic resin, alkyl vinyl ether graft copolymer and polydimethylsiloxane is 100:0.5-1.2:0.6-1.

5.

7. A carbon nanotube modified acrylic resin coating, characterized in that: The carbon nanotube-modified acrylic resin coating in step (4) is applied in the field of coating materials.

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