Functionalized carbon nanotube modified epoxy resin antibacterial coating and preparation method thereof

Abstract

The invention relates to the technical field of epoxy resin coatings, and discloses a functionalized carbon nanotube modified epoxy resin antibacterial coating, the epoxy resin coating modified by amino-containing quaternized piperazine-based carbon nanotubes has a stronger antibacterial effect, and when the carbon nanotubes are added into the epoxy resin coating as a common inorganic additive, the antibacterial effect of the epoxy resin coating is improved. The piperazinyl quaternary ammonium salt has good biological activity and has a remarkable inactivation effect on bacteria, after alkyl bacteria are killed, the quaternary ammonium salt can still keep sufficient activity, the quaternary ammonium salt is grafted to the surface of the carbon nano tube, the quaternary ammonium salt and the carbon nano tube can generate a synergistic effect, and the antibacterial effect of the carbon nano tube is improved; moreover, the antibacterial stability of the epoxy resin coating is improved, amino contained at the tail end of quaternary ammonium salt has a certain promotion effect on an acid anhydride epoxy resin curing agent, and the mechanical property of the coating is improved by adding the carbon nanotubes.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy resin coatings, in particular to a functionalized carbon nanotube-modified epoxy resin antibacterial coating and a preparation method thereof. Background Art

[0002] Finding more suitable antibacterial substances has become the top priority for improving the antibacterial effect. It should be noted that bacterial and fungal infections usually occur on the surface of materials. The use of antibacterial coatings is one of the important methods to improve the antibacterial effect of equipment. For this reason, researchers have done a lot of research, such as the Chinese patent publication number CN105482536A, which discloses a transparent antibacterial hydrophilic coating, and the Chinese patent publication number CN104356873A, which discloses an epoxy anticorrosive antibacterial coating. Although both increase the antibacterial properties of the coating, they still have the problems of high addition amount and unsatisfactory antibacterial effect.

[0003] A variety of antibacterial materials have been reported. Carbon nanotubes are conventional inorganic additives that have strong antibacterial effects on a variety of bacteria and viruses. The antibacterial properties of carbon nanotubes are mainly caused by active oxygen, physical perforation / capture effects, hydrophobic-hydrophilic interactions and electrostatic repulsion. However, the antibacterial effect of carbon nanotubes alone is not ideal. Modification of carbon nanotubes has become an important means to increase the antibacterial effect of carbon nanotubes. Quaternary ammonium salts and their derivatives have a variety of uses, such as softeners, antistatic agents, asphalt emulsifiers, dye leveling agents and antibacterial agents. In these fields, antibacterial properties have been most widely studied because their positively charged cationic parts give them special adsorption and application characteristics. However, the use of quaternary ammonium salts alone is prone to small molecule precipitation, making the antibacterial effect unstable. Grafting them on the surface of inorganic substances can avoid such problems. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a functionalized carbon nanotube-modified epoxy resin antibacterial coating and a preparation method thereof, which solves the problems of poor antibacterial property and low mechanical properties of epoxy resin coatings.

[0005] To achieve the above object, the present invention provides the following technical solution: a functionalized carbon nanotube-modified epoxy resin antibacterial coating, wherein the preparation method of the functionalized carbon nanotube-modified epoxy resin antibacterial coating comprises the following steps: (1) placing the carboxylated carbon nanotubes in a reaction bottle, then adding thionyl chloride thereto, stirring evenly and reacting at 60-90°C for 18-36 hours. After the reaction is completed, vacuum rotary evaporation of the solvent is performed to obtain acyl chloride carbon nanotubes; (2) ultrasonically dispersing the acyl chloride carbon nanotubes and N-ethylpiperazine in dichloromethane, stirring them evenly, and reacting them. After the reaction is completed, filtering them, and washing them with deionized water until they are neutral, thereby obtaining piperazine-based carbon nanotubes; (3) ultrasonically dispersing piperazine carbon nanotubes and 4-bromobutylamine hydrobromide in an acetonitrile solvent, and then refluxing under a nitrogen atmosphere to react. After the reaction is completed, filtering, and washing with deionized water and ethanol to obtain amino-containing quaternized piperazine carbon nanotubes; (4) Place a water-based epoxy resin in a reaction bottle, add amino-containing quaternized piperazine carbon nanotubes, stir evenly, disperse at a speed of 1800-3000 r / min for 15-40 min, grind with a sand mill for 8-20 min, add a defoaming agent polyether modified silicone and a leveling agent polydimethylsiloxane, stir evenly, add a curing agent, let stand and defoam for 2-6 min, and obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating.

[0006] Preferably, in step (1), the mass ratio of carboxylated carbon nanotubes to thionyl chloride is 100:3000-6000.

[0007] Preferably, in step (2), the mass ratio of the chlorinated carbon nanotubes, N-ethylpiperazine and dichloromethane is 10:35-80:250-600.

[0008] Preferably, in step (2), the reaction temperature is 0-10° C. and the reaction time is 1-3 h.

[0009] Preferably, in step (3), the mass ratio of piperazine carbon nanotubes, 4-bromo-butylamine hydrobromide and acetonitrile is 100:35-100:3000-8000.

[0010] Preferably, in step (3), the reaction temperature is 60-100° C. and the reaction time is 3-8 h.

[0011] Preferably, the type of curing agent in step (4) is any one of alkenyl succinic anhydride or trimellitic anhydride.

[0012] Preferably, in step (4), the mass ratio of the waterborne epoxy resin, the amino-quaternized piperazine-based carbon nanotubes, the defoamer polyether-modified silicone, the leveling agent polydimethylsiloxane and the curing agent is 100:2-5:0.08-0.2:0.01-0.03:18-30.

[0013] Compared with the prior art, the present invention has the following experimental principles and beneficial technical effects: The functionalized carbon nanotube modified epoxy resin antibacterial coating comprises the following steps: firstly, carboxyl carbon nanotubes are modified by using thionyl chloride to obtain acyl chloride carbon nanotubes, then the acyl chloride groups of the acyl chloride carbon nanotubes are subjected to an amidation reaction with the imino groups in N-ethylpiperazine to obtain piperazine carbon nanotubes, then 4-bromo-butylamine hydrobromide is used as a quaternization agent to carry out a quaternization reaction on the tertiary amine groups of the piperazine carbon nanotubes to obtain amino-containing quaternized piperazine carbon nanotubes, and finally the amino-containing quaternized piperazine carbon nanotubes are used as antibacterial additives to prepare the functionalized carbon nanotube modified epoxy resin antibacterial coating by mechanical blending.

[0014] The functionalized carbon nanotube-modified epoxy resin antibacterial coating has a stronger antibacterial effect than pure epoxy resin coating. The carbon nanotubes are common inorganic additives. When added to epoxy resin coating, the antibacterial effect can be significantly improved. Due to the nanometer-level structure of the carbon nanotubes, when the carbon nanotubes come into contact with bacterial cells, the bacterial cell membrane can undergo physical deformation, causing the bacterial cell membrane to be physically damaged, the cytoplasm and a large amount of nutrients to be lost, and the bacteria to lose activity, thereby achieving the antibacterial effect. Moreover, the high specific surface area gives the carbon nanotubes high adsorption performance, which can produce ideal adsorption behavior on bacterial cells, further improving the inactivation effect of the epoxy resin coating on bacteria. In addition, the carbon nanotubes can also produce oxidative stress behavior on bacterial cells, causing damage to the bacterial cells by causing an imbalance between antioxidants and strong oxidants in the bacterial cells. The piperazine quaternary ammonium salt has good biological activity and has a significant inactivation effect on bacteria. The quaternary ammonium salt has an electrostatic adsorption behavior between charges, which has an effect on bacterial cells. The carbon nanotubes have sufficient adsorption capacity, and when the piperazine quaternary ammonium salt molecules come into contact with bacterial cells, the hydrophobic long chains therein can come into contact with the bacterial cell membrane and destroy the cell membrane. The positive charge of the nitrogen atom can also cause the protein to deteriorate and inactivate the bacteria. After killing the alkanes, the quaternary ammonium salt can still maintain sufficient activity and continue to be antibacterial. The quaternary ammonium salt is grafted on the surface of the carbon nanotubes, which can not only make the two have a synergistic effect, further improve the antibacterial effect of the epoxy resin coating, but also avoid the precipitation of the quaternary ammonium salt molecules during use, and increase the antibacterial stability of the epoxy resin coating. In addition, the amino group contained in the end of the quaternary ammonium salt has a certain promoting effect on the anhydride epoxy resin curing agent, and can act as an amine accelerator, which not only improves the performance of the cured product, but also reduces the amount of curing agent used and reduces its harm. The carbon nanotubes have strong mechanical properties, and adding them to the coating can increase its mechanical properties. When subjected to external forces, the stress is dispersed inside the coating through the organic-inorganic network structure formed between the carbon nanotubes and the organic matrix, which reduces the damage caused by stress concentration and improves the mechanical strength of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the reaction formula of acyl chloride carbon nanotubes and N-ethylpiperazine; Figure 2 is the reaction formula of piperazine-based carbon nanotubes and 4-bromo-butylamine hydrobromide. DETAILED DESCRIPTION

[0016] To achieve the above object, the present invention provides the following specific implementation methods and examples: A functionalized carbon nanotube-modified epoxy resin antibacterial coating, the preparation method of which comprises the following steps: (1) placing carboxylated carbon nanotubes in a reaction bottle at a mass ratio of 100:3000-6000, then adding thionyl chloride thereto, stirring evenly and reacting at 60-90° C. for 18-36 hours. After the reaction is completed, vacuum rotary evaporation of the solvent is performed to obtain acyl chloride carbon nanotubes; (2) ultrasonically dispersing acyl chloride carbon nanotubes and N-ethylpiperazine in dichloromethane at a mass ratio of 10:35-80:250-600, stirring evenly, reacting at 0-10°C for 1-3h, filtering after the reaction, and washing with deionized water until neutral to obtain piperazine-based carbon nanotubes; (3) ultrasonically dispersing piperazine carbon nanotubes and 4-bromobutylamine hydrobromide in an acetonitrile solvent at a mass ratio of 100:35-100:3000-8000, and then refluxing under a nitrogen atmosphere, reacting at 60-100° C. for 3-8 hours. After the reaction is completed, filtering, washing with deionized water and ethanol, and obtaining amino-containing quaternized piperazine carbon nanotubes; (4) According to the mass ratio of 100:2-5:0.08-0.2:0.01-0.03:18-30, a water-based epoxy resin is placed in a reaction bottle, and then amino-containing quaternized piperazine carbon nanotubes are added. After stirring evenly, the mixture is dispersed at a speed of 1800-3000 r / min for 15-40 minutes, and then ground with a sand mill for 8-20 minutes. Then, a defoaming agent polyether modified silicone and a leveling agent polydimethylsiloxane are added. After stirring evenly, a curing agent is added thereto, wherein the type of the curing agent is any one of alkenyl succinic anhydride or trimellitic anhydride. The mixture is allowed to stand and defoam for 2-6 minutes to obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating. Example 1

[0017] (1) 4 g of carboxylated carbon nanotubes were placed in a reaction bottle, and then 120 g of thionyl chloride was added thereto. The mixture was stirred evenly and reacted at 60 °C for 18 h. After the reaction was completed, the solvent was evaporated by vacuum rotary evaporation to obtain acyl chloride carbon nanotubes; (2) Ultrasonic dispersion of 2.5 g of acyl chloride carbon nanotubes and 8.75 g of N-ethylpiperazine in 62.5 g of dichloromethane, stirring evenly, reacting at 0°C for 1 h. After the reaction is completed, filtering, washing with deionized water until neutral, and obtaining piperazine-based carbon nanotubes; (3) 2 g of piperazine carbon nanotubes and 0.7 g of 4-bromo-butylamine hydrobromide were ultrasonically dispersed in 60 g of acetonitrile solvent, and then refluxed under a nitrogen atmosphere and reacted at 60 ° C for 3 h. After the reaction was completed, the mixture was filtered and washed with deionized water and ethanol to obtain amino-containing quaternized piperazine carbon nanotubes; (4) Place 10 g of water-based epoxy resin in a reaction bottle, add 0.2 g of amino-containing quaternized piperazine carbon nanotubes, stir evenly, disperse at a speed of 1800 r / min for 15 min, grind with a sand mill for 8 min, then add 0.008 g of defoaming agent polyether modified silicone and 0.001 g of leveling agent polydimethylsiloxane, stir evenly, and then add 1.8 g of curing agent, wherein the type of curing agent is any one of alkenyl succinic anhydride or trimellitic anhydride, let it stand and defoam for 2 min, and obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating. Example 2

[0018] (1) 4 g of carboxylated carbon nanotubes were placed in a reaction bottle, and then 160 g of thionyl chloride was added thereto. The mixture was stirred evenly and reacted at 70 °C for 20 h. After the reaction was completed, the solvent was evaporated by vacuum rotary evaporation to obtain acyl chloride carbon nanotubes; (2) Ultrasonic dispersion of 2.5 g of acyl chloride carbon nanotubes and 10 g of N-ethylpiperazine in 80 g of dichloromethane, stirring evenly, reacting at 2°C for 1.5 h. After the reaction is complete, filtering, washing with deionized water until neutral, and obtaining piperazine-based carbon nanotubes; (3) 2 g of piperazine carbon nanotubes and 0.9 g of 4-bromo-butylamine hydrobromide were ultrasonically dispersed in 80 g of acetonitrile solvent, and then refluxed under a nitrogen atmosphere and reacted at 65 °C for 4 h. After the reaction was completed, the mixture was filtered and washed with deionized water and ethanol to obtain amino-containing quaternized piperazine carbon nanotubes; (4) Place 10 g of water-based epoxy resin in a reaction bottle, add 0.25 g of amino-containing quaternized piperazine carbon nanotubes, stir evenly, disperse at a speed of 2000 r / min for 20 min, grind with a sand mill for 10 min, then add 0.01 g of defoaming agent polyether modified silicone and 0.0015 g of leveling agent polydimethylsiloxane, stir evenly, and then add 2 g of curing agent, wherein the type of curing agent is any one of alkenyl succinic anhydride or trimellitic anhydride, let it stand and defoam for 3 min, and obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating. Example 3

[0019] (1) 4 g of carboxylated carbon nanotubes were placed in a reaction bottle, and then 200 g of thionyl chloride was added thereto. The mixture was stirred evenly and reacted at 75 °C for 28 h. After the reaction was completed, the solvent was evaporated by vacuum rotary evaporation to obtain acyl chloride carbon nanotubes. (2) Ultrasonic dispersion of 2.5 g of acyl chloride carbon nanotubes and 12 g of N-ethylpiperazine in 100 g of dichloromethane, stirring evenly, and reacting at 5 °C for 23 h. After the reaction is completed, filtering, and washing with deionized water until neutral to obtain piperazine-based carbon nanotubes; (3) 2 g of piperazine carbon nanotubes and 1.4 g of 4-bromo-butylamine hydrobromide were ultrasonically dispersed in 100 g of acetonitrile solvent, and then refluxed under a nitrogen atmosphere and reacted at 80 ° C for 5 h. After the reaction was completed, the mixture was filtered and washed with deionized water and ethanol to obtain amino-containing quaternized piperazine carbon nanotubes; (4) Place 10 g of water-based epoxy resin in a reaction bottle, add 0.35 g of amino-containing quaternized piperazine carbon nanotubes, stir evenly, disperse at a speed of 2400 r / min for 25 min, grind with a sand mill for 14 min, then add 0.014 g of defoaming agent polyether modified silicone and 0.002 g of leveling agent polydimethylsiloxane, stir evenly, and then add 2.4 g of curing agent, wherein the type of curing agent is either alkenyl succinic anhydride or trimellitic anhydride, let stand and defoam for 4 min, and obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating. Example 4

[0020] (1) 4 g of carboxylated carbon nanotubes were placed in a reaction bottle, and then 220 g of thionyl chloride was added thereto. The mixture was stirred evenly and reacted at 80 °C for 32 h. After the reaction was completed, the solvent was evaporated by vacuum rotary evaporation to obtain acyl chloride carbon nanotubes. (2) Ultrasonic dispersion of 2.5 g of acyl chloride carbon nanotubes and 18 g of N-ethylpiperazine in 140 g of dichloromethane, stirring evenly, reacting at 8 °C for 2.8 h, filtering after the reaction, and washing with deionized water until neutral to obtain piperazine-based carbon nanotubes; (3) 2 g of piperazine carbon nanotubes and 1.8 g of 4-bromo-butylamine hydrobromide were ultrasonically dispersed in 150 g of acetonitrile solvent, and then refluxed under a nitrogen atmosphere and reacted at 90 °C for 7 h. After the reaction was completed, the mixture was filtered and washed with deionized water and ethanol to obtain amino-containing quaternized piperazine carbon nanotubes; (4) Place 10 g of water-based epoxy resin in a reaction bottle, add 0.4 g of amino-containing quaternized piperazine carbon nanotubes, stir evenly, disperse at a speed of 2800 r / min for 32 min, grind with a sand mill for 16 min, then add 0.018 g of defoaming agent polyether modified silicone and 0.0025 g of leveling agent polydimethylsiloxane, stir evenly, and then add 2.6 g of curing agent, wherein the type of curing agent is any one of alkenyl succinic anhydride or trimellitic anhydride, let stand and defoam for 5 min, and obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating. Example 5

[0021] (1) 4 g of carboxylated carbon nanotubes were placed in a reaction bottle, and then 240 g of thionyl chloride was added thereto. The mixture was stirred evenly and reacted at 90 °C for 36 h. After the reaction was completed, the solvent was evaporated by vacuum rotary evaporation to obtain acyl chloride carbon nanotubes. (2) Ultrasonic dispersion of 2.5 g of acyl chloride carbon nanotubes and 20 g of N-ethylpiperazine in 150 g of dichloromethane, stirring evenly, reacting at 10 ° C for 3 h, filtering after the reaction, and washing with deionized water until neutral to obtain piperazine-based carbon nanotubes; (3) 2 g of piperazine carbon nanotubes and 2 g of 4-bromo-butylamine hydrobromide were ultrasonically dispersed in 160 g of acetonitrile solvent, and then refluxed under a nitrogen atmosphere and reacted at 100 °C for 8 h. After the reaction was completed, the mixture was filtered and washed with deionized water and ethanol to obtain amino-containing quaternized piperazine carbon nanotubes; (4) Place 10 g of water-based epoxy resin in a reaction bottle, add 0.5 g of amino-containing quaternized piperazine carbon nanotubes, stir evenly, disperse at a speed of 3000 r / min for 40 min, grind with a sand mill for 20 min, then add 0.02 g of defoaming agent polyether modified silicone and 0.003 g of leveling agent polydimethylsiloxane, stir evenly, and then add 3 g of curing agent, wherein the type of curing agent is any one of alkenyl succinic anhydride or trimellitic anhydride, let it stand and defoam for 6 min, and obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating.

[0022] Comparative Example 1 (1) 4 g of carboxylated carbon nanotubes were placed in a reaction bottle, and then 160 g of thionyl chloride was added thereto. The mixture was stirred evenly and reacted at 80 °C for 24 h. After the reaction was completed, the solvent was evaporated by vacuum rotary evaporation to obtain acyl chloride carbon nanotubes; (2) Ultrasonic dispersion of 2.5 g of acyl chloride carbon nanotubes and 10 g of N-ethylpiperazine in 80 g of dichloromethane, stirring evenly, reacting at 5 °C for 2 h, filtering after the reaction, and washing with deionized water until neutral to obtain piperazine-based carbon nanotubes; (3) Place 10 g of water-based epoxy resin in a reaction bottle, add 0.4 g of piperazine-based carbon nanotubes, stir evenly, disperse at a speed of 2400 r / min for 20 min, grind with a sand mill for 10 min, then add 0.008 g of defoaming agent polyether-modified silicone and 0.001 g of leveling agent polydimethylsiloxane, stir evenly, and then add 2 g of curing agent, wherein the type of curing agent is either alkenyl succinic anhydride or trimellitic anhydride. Let stand and defoam for 3 min to obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating.

[0023] The antibacterial (Staphylococcus aureus) test of functionalized carbon nanotube modified epoxy resin antibacterial coating was carried out according to the national standard HG-T 3950-2007.

[0024]

[0025] The mechanical properties of functionalized carbon nanotube modified epoxy resin antibacterial coatings were tested according to the national standard GB / T 2546.2-2003.

[0026]

Claims

1. A functionalized carbon nanotube-modified epoxy resin antibacterial coating, characterized in that: The preparation method of the functionalized carbon nanotube-modified epoxy resin antibacterial coating comprises the following steps: (1) placing the carboxylated carbon nanotubes in a reaction bottle, then adding thionyl chloride thereto, stirring evenly and reacting at 60-90°C for 18-36 hours. After the reaction is completed, vacuum rotary evaporation of the solvent is performed to obtain acyl chloride carbon nanotubes; (2) ultrasonically dispersing the acyl chloride carbon nanotubes and N-ethylpiperazine in dichloromethane, stirring them evenly, and reacting them. After the reaction is completed, filtering them, and washing them with deionized water until they are neutral, thereby obtaining piperazine-based carbon nanotubes; (3) ultrasonically dispersing piperazine carbon nanotubes and 4-bromobutylamine hydrobromide in an acetonitrile solvent, and then refluxing under a nitrogen atmosphere to react. After the reaction is completed, filtering, and washing with deionized water and ethanol to obtain amino-containing quaternized piperazine carbon nanotubes; (4) Place a water-based epoxy resin in a reaction bottle, add amino-containing quaternized piperazine carbon nanotubes, stir evenly, disperse at a speed of 1800-3000 r / min for 15-40 min, grind with a sand mill for 8-20 min, add a defoaming agent polyether modified silicone and a leveling agent polydimethylsiloxane, stir evenly, add a curing agent, let stand and defoam for 2-6 min, and obtain a functionalized carbon nanotube-modified epoxy resin antibacterial coating.

2. The functionalized carbon nanotube-modified epoxy resin antibacterial coating according to claim 1, characterized in that: In the step (1), the mass ratio of the carboxylated carbon nanotubes to the dithionyl chloride is 100:3000-6000.

3. The functionalized carbon nanotube-modified epoxy resin antibacterial coating according to claim 1, characterized in that: In the step (2), the mass ratio of the chlorinated carbon nanotubes, N-ethylpiperazine and dichloromethane is 10:35-80:250-600.

4. The functionalized carbon nanotube-modified epoxy resin antibacterial coating according to claim 1, characterized in that: In the step (2), the reaction temperature is 0-10°C and the reaction time is 1-3h.

5. The functionalized carbon nanotube-modified epoxy resin antibacterial coating according to claim 1, characterized in that: In the step (3), the mass ratio of piperazine-based carbon nanotubes, 4-bromo-butylamine hydrobromide and acetonitrile is 100:35-100:3000-8000.

6. The functionalized carbon nanotube-modified epoxy resin antibacterial coating according to claim 1, characterized in that: In the step (3), the reaction temperature is 60-100° C. and the reaction time is 3-8 h.

7. The functionalized carbon nanotube-modified epoxy resin antibacterial coating according to claim 1, characterized in that: The type of curing agent in step (4) is any one of alkenyl succinic anhydride and trimellitic anhydride.

8. The functionalized carbon nanotube-modified epoxy resin antibacterial coating according to claim 1, characterized in that: In the step (4), the mass ratio of the waterborne epoxy resin, the amino quaternized piperazine carbon nanotubes, the defoamer polyether modified silicone, the leveling agent polydimethylsiloxane and the curing agent is 100:2-5:0.08-0.2:0.01-0.03:18-30.

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