CN113214603B - A kind of carbon nanotube epoxy resin composite material electrode, its preparation method and use - Google Patents

Abstract

The invention discloses a carbon nanotube epoxy resin composite material electrode, which comprises an electrode body, an electrode tube and an electrode lead; the electrode body is filled at one end of the electrode tube, and the bottom is circular; the electrode lead extends from the electrode body Lead out and lead out from the other end of the electrode tube; the electrode body includes carbon nanotubes containing a curing agent and epoxy resin is obtained by polycondensation, wherein the mass of the carbon nanotubes is 10-50% of the mass of the electrode body. The invention also discloses a preparation method of the carbon nanotube epoxy resin composite material electrode and an application for detecting chemical components in tobacco. The carbon nanotube epoxy resin composite material electrode of the invention has the advantages of high sensitivity, good reproducibility, strong anti-pollution ability and the like.

Description

A carbon nanotube epoxy resin composite electrode, its preparation method and application

technical field

The invention belongs to the technical field of tobacco chemistry, and in particular relates to a carbon nanotube epoxy resin composite electrode, its preparation method and application.

Background technique

In 1991, Iijima, Japan first discovered carbon nanotubes ^[1] , which have a needle-like tubular structure of graphitic carbon, and its carbon atoms form a coaxial cylinder with several to dozens of layers. As a one-dimensional nanomaterial, carbon nanotubes have many unusual mechanical, electrical, and chemical properties due to their light weight and perfectly connected hexagonal structure. In recent years, with the in-depth research of carbon nanotubes and nanomaterials, their broad application prospects are constantly showing. Carbon nanotubes, also known as bucky tubes, are one-dimensional quantum materials whose radial dimensions are on the order of nanometers and axial dimensions are on the order of microns, and both ends of the tube are basically sealed. Carbon nanotubes are mainly composed of carbon atoms arranged in a hexagonal shape to form coaxial circular tubes with several to dozens of layers. The distance between layers is kept fixed, about 0.34nm, and the diameter is generally 2 to 20nm. According to the different orientations of the carbon hexagon along the axial direction, it can be divided into three types: zigzag, armchair and spiral. Carbon nanotubes can be classified into multi-walled carbon nanotubes or single-walled carbon nanotubes according to the number of layers. Due to the excellent physical and chemical properties of carbon nanotubes, they have shown good application prospects in the fields of electronics, biomedicine, aerospace, military, energy, lasers, medical treatment and sensors ^[2,3] .

Carbon nanotubes have extremely high electrical conductivity and electrocatalytic activity, which have unique advantages in the preparation of electrochemical sensors, and have been successfully used to enhance the electrochemical response materials of some biologically active substances. The preparation methods of carbon nanotube-based electrodes for electrochemical detection mainly include surface modification, electrochemical polymerization surface modification, and paraffin oil mixed filling method, among which surface modification is the most commonly used method. The surface modification method is to disperse the carbon nanotube powder in a solvent, and then coat it on the surface of the substrate electrode. However, since the carbon nanotube modification layer is easy to fall off in actual use, the electrode stability is not good and the service life is not long. The paraffin oil mixed filling method is to mix carbon nanotube powder and paraffin oil and fill it in the electrode tube; however, the electrode body is a paste, which is a non-rigid material, and it will be deformed during use, and the noise and signal are heavy in electrochemical detection. The current performance is not good, and it is a disposable electrode. The electrochemical polymerization surface modification method is to disperse carbon nanotubes in a conductive polymer monomer solution, form a surface modification layer through electrochemical polymerization, and fix the carbon nanotubes on the surface of the electrode; but the prepared electrode also has a carbon nanotube modification layer The problem of shedding affects the stability and service life of the electrode. In view of the deficiencies and problems of the original carbon nanotube electrodes, it is an important way to improve the stability and performance of carbon nanotube electrodes by combining polymers and carbon nanotubes to prepare composite electrodes. Epoxy resin is an important class of thermosetting plastics, widely used in construction, military, adhesives, coatings and many other fields ^[5] . At present, bisphenol A epoxy resin is the most produced and widely used epoxy resin, which has the advantages of stable chemical properties, resistance to organic solvents, heat resistance, good electrical insulation, and excellent mechanical and mechanical properties.

Tobacco contains electrochemically active components such as phenols, flavonoids, alkaloids, amino acids, etc. The quality of tobacco can be inspected by detecting these chemical components ^[6] . Electrochemical detection has the advantages of good selectivity and high sensitivity.

references

[1] Iijima, S., Helical microtubules of graphitic carbon [J]. Nature, 1991, 354(6348): 56-58.

[2] Zhang, J., Tahmasebid, A., Omoriyekomwana, J.E., Yu, J.L., Microwave-assisted synthesis of biochar-carbon-nanotube-NiO composite as high-performance anode materials for lithium-ion batteries, Fuel Processing Technology, 2021 ,213,106714.

[3] Rajabathar, J.R., Periyasami, G., Alanazi, A.M., Govindasamy, M., Arunachalam, P., Review on carbon nanotube varieties for healthcare application: effect of preparation methods and mechanism insight, Processes, 2020, 1654.

[4] Zhang, F.L., Zhang, L., Yaseen, M., Huang, K.A review on the self-healing ability of epoxy polymers, A review on the self-healing ability of epoxy polymers, Journal of Applied Polymer Science, 2021, 138 ,e50260.

[5] Giovanni, M., Poh H.L., Ambrosi A., Zhao G., Sofer Z., Sanek F., Khezri B., Webster R.D., Pumera M., Nanoscale 2012, 4, 5002-5008.

[6] Soares, F.A., Chiapetta, S.C., Pacheco, W.F., Development of ananalytical method for the determination of N-nitrosamines in tobacco by GC-NCD after solid phase extraction, ANalytical Methods, 2017, 9, 2284-2289.

Contents of the invention

The object of the present invention is to propose a carbon nanotube epoxy resin composite material electrode of tobacco chemical composition with high detection sensitivity, high mechanical strength and long service life and a rapid preparation method thereof.

Technical scheme of the present invention is as follows:

The first aspect of the present invention discloses a carbon nanotube epoxy resin composite electrode, which includes an electrode body, an electrode tube, and an electrode lead; the electrode body is filled at one end of the electrode tube, and the bottom is round; the electrode lead Lead out from the electrode body and lead out from the other end of the electrode tube; the electrode body is obtained by polycondensation of carbon nanotubes including curing agent and epoxy resin, wherein the mass of carbon nanotubes is 10-50% of the mass of the electrode body.

Preferably, the electrode tube is made of an electrical insulating material, the electrode tube is a plastic tube, a ceramic tube, a quartz tube or a glass tube, and the inner diameter of the electrode tube is 25um-8mm; An adhesive is used to fix it on the other end of the electrode tube and seal the end of the electrode tube. The adhesive is one of hot melt adhesive, epoxy resin, silicone glue or ethyl α-cyanoacrylate.

Preferably, the carbon nanotubes are single-walled carbon nanotubes or multi-walled carbon nanotubes treated with nitric acid.

The second aspect of the present invention discloses the preparation method of the carbon nanotube epoxy resin composite electrode, comprising the following steps:

(1) Mix carbon nanotube powder, epoxy resin prepolymer and curing agent by a certain mass ratio to obtain a black viscous mixture with certain plasticity;

(2) filling the mixture obtained in step (1) into one end of the electrode tube, and then inserting the electrode lead into the mixture through the other end of the electrode tube;

(3) curing the electrode tube obtained in step (2) for a period of time under infrared rays and a certain temperature;

(4) One end of the solidified electrode tube in step (3) is polished into a circle; the electrode lead is fixed on the other end of the electrode tube with an adhesive, and the end electrode tube is sealed; the carbon Nanotube epoxy composite electrodes.

Preferably, the carbon nanotubes in step (1) are treated with nitric acid as follows: disperse the carbon nanotubes in nitric acid, heat them at a temperature of 50-95° C. for 8-15 hours, cool to room temperature, filter under reduced pressure, and wash , until the pH value of the filtrate is higher than 5, the solid is heated and dried to obtain carbon nanotubes treated with nitric acid. The purpose of treating carbon nanotubes with nitric acid is to remove metal impurities and oxidized carbon nanotubes. At the same time, carboxyl groups can be introduced on the surface of carbon nanotubes through nitric acid oxidation, which can improve the binding ability of carbon nanotubes and epoxy resin and improve the stability of electrodes. and conductivity; the nitric acid used is concentrated nitric acid.

Preferably, the carbon nanotubes described in step (1) are single-walled carbon nanotubes or multi-walled carbon nanotubes; the quality of the carbon nanotubes is the carbon nanotube powder, epoxy resin prepolymer and curing agent 10-50%.

Preferably, the electrode tube in step (2) is made of an electrical insulating material, the electrode tube is a plastic tube, a ceramic tube, a quartz tube or a glass tube, and the inner diameter of the electrode tube is 25um-8mm; step (4 ) said adhesive is one of hot melt adhesive, epoxy resin, silicone glue or α-ethyl cyanoacrylate.

Preferably, the wavelength of the infrared rays in step (3) is 1.40-11000um, the curing temperature is 80-120°C, and the curing time is 5-20min.

More preferably, the wavelength of the infrared rays in step (3) is 3-100um, the curing temperature is 100°C, and the curing time is 10min.

The third aspect of the present invention discloses the use of the carbon nanotube epoxy resin composite electrode for detecting chemical components in tobacco.

Beneficial effects of the present invention:

1. The present invention utilizes the technical advantages of the bulk polycondensation of thermoplastic epoxy resin, and directly conducts in-situ polycondensation by infrared heating in the insulating material tube body to prepare a rigid carbon nanotube epoxy resin composite material electrode. Since the carbon nanotube epoxy resin composite electrode body formed by in-situ condensation in the new electrode is rigid, the performance, mechanical strength, stability and service life of the electrode are greatly improved, and it can be directly polished and updated to avoid carbon nanotubes being damaged during use. Shedding of material.

2. The carbon nanotubes in the carbon nanotube epoxy resin composite electrode of the present invention are uniformly dispersed in the epoxy resin, forming a good composite conductive system, having significant electrocatalytic activity, high sensitivity, and reproducible detection Good performance and strong anti-pollution ability. It can be used for electrochemical detection of microfluidic chip electrophoresis, flow injection analysis, liquid chromatography, etc., and can also be used for electrochemical analysis such as voltammetry, amperometry, and coulometric analysis. Not only can it be used for electrochemical detection of tobacco chemical components such as phenols, flavonoids and alkaloids, but it can also be used in food and drug analysis, environmental monitoring and clinical diagnosis and other fields. with broadly application foreground.

3. The preparation method of the carbon nanotube epoxy resin composite electrode of the present invention is simple in process, low in raw material cost, and can be processed in batches. The present invention uses mid-infrared and far-infrared light with a wavelength of 1.40-11000um to heat and cure to prepare carbon nanotube epoxy resin composite electrodes, which is the first invention of the present invention. Because the wavelength of the absorption spectrum of the organic matter including the polymer is in the same range as the wavelength of the middle and far infrared rays, the absorption of the middle and far infrared rays is very strong, so the middle and far infrared radiation is very suitable for the heating and curing of the carbon nanotube epoxy resin composite material of the present invention. The heat source has fast heating speed and high heating efficiency. It can start or stop working in a short time, and it is easy to realize intelligent control. Usually, the epoxy resin prepolymer containing curing agent needs more than 24 hours to cure at room temperature, and it takes more than 3 hours to heat polycondensation and cure in an ordinary oven; and the present invention uses mid-infrared and far-infrared light, and the temperature is about 100 ℃. , The epoxy resin prepolymer containing curing agent and its mixed material with carbon nanotubes can be completely cured in about 10 minutes, and the curing efficiency is obviously improved.

4. Before use, the carbon nanotubes of the present invention are treated with concentrated nitric acid to remove metal impurities and oxidized carbon nanotubes. At the same time, carboxyl groups can be introduced on the surface of carbon nanotubes through the oxidation of concentrated nitric acid, which can improve the bond between carbon nanotubes and epoxy. The binding ability of the resin improves the stability and conductivity of the electrode.

Description of drawings

1 is a flow chart of the preparation of the carbon nanotube epoxy resin composite electrode of the present invention, wherein (D) is the finished product of the carbon nanotube epoxy resin composite electrode.

Fig. 2 is a structural schematic diagram of a metal box with ventilation holes for infrared light curing.

3 is a scanning electron micrograph (B) of the cross-section of the carbon nanotube epoxy resin composite electrode of Example 1 and a scanning electron micrograph (A) of the multi-walled carbon nanotubes used, both of which have a magnification of 20,000 times.

FIG. 4 is a Raman spectrum diagram of the carbon nanotube epoxy resin composite electrode of Example 1. FIG.

Figure 5 shows the carbon nanotube epoxy resin composite electrodes prepared by infrared light heating and curing, and the carbon nanotube epoxy resin composite electrodes prepared by ordinary heating and curing methods. The electrophoretic spectrum of the mixed solution with quercetin standard, the detection temperature is 100 ° C; where (A) is the detection result of the carbon nanotube epoxy resin composite electrode prepared by the common heating and curing method; (B) is the infrared light heating and curing method The detection results of carbon nanotube epoxy resin composite electrodes.

Fig. 6 is the capillary electrophoresis spectrum of the carbon nanotube epoxy resin composite electrode obtained in Example 1 for detecting methanol extract of tobacco leaves.

Fig. 7 shows the influence of different infrared irradiation time and temperature on the response sensitivity of the prepared carbon nanotube epoxy resin composite electrode to the detection of nicotine.

Fig. 8 is the voltammetry curve under 0.5mM rutin for preparing carbon nanotube epoxy resin composite electrode by infrared light heating and curing, and preparing carbon nanotube epoxy resin composite electrode by common heating curing method; the temperature is 100 ℃, scanning speed: 100 mV/s. Among them (A) is the detection result of carbon nanotube epoxy resin composite electrode prepared by infrared light heating and curing method; (B) is the detection result of carbon nanotube epoxy resin composite electrode prepared by ordinary heating and curing method.

Reference signs are: 1. electrode tube; 2. electrode lead; 3. carbon nanotube epoxy resin prepolymer mixture; 4. carbon nanotube epoxy resin composite material electrode body; 5. adhesive; 6. tape 7. Infrared light; 8. Carbon nanotube epoxy resin composite electrode; 9. Thermocouple; 10. Fan; 11. Temperature controller.

Detailed ways

Further illustrate the present invention below by embodiment and accompanying drawing.

Embodiment 1: Preparation of carbon nanotube epoxy resin composite electrode

Disperse 2 grams of commercial carbon nanotubes with a purity higher than 95% in a flask filled with 500 ml of concentrated nitric acid, heat treatment in a water bath at 60°C for 12 hours, and mechanically stir the mixture in the bottle at a speed of 120 rpm minute. After the nitric acid oxidation heat treatment mixture is cooled to room temperature, filter it under reduced pressure, and wash it with a large amount of water by means of a water pump, and continuously check with pH test paper until the pH value of the filtrate is higher than 5. Then, the solid was placed in a metal box with air holes in FIG. 2, and dried at 110° C. for 20 minutes to obtain nitric acid oxidation-treated carbon nanotubes.

The preparation process of the carbon nanotube epoxy resin composite electrode is shown in Figure 1. Mix the E51 type epoxy resin prepolymer and the supporting epoxy resin curing agent ethylenediamine in a mass ratio of 10:1; weigh 0.5 gram of the above nitric acid-treated carbon nanotube powder and 1 gram of the curing agent-containing Epoxy resin prepolymers were mixed and fully stirred to obtain a certain plastic black viscous mixture 3; one end of a fused silica capillary 1 with an inner diameter of 320 microns, an outer diameter of 450 microns and a length of 5 cm was inserted into the black viscous mixture, The black viscous mixture 3 is filled in the capillary to a filling depth of about 4 mm; then a copper wire 2 with a length of 10 cm and a diameter of 150 microns is inserted into the fused silica capillary 1 through the other opening until the copper wire 2 is inserted into the capillary 1 In the black viscous mixture 3 in about 2 mm, to ensure good contact; then place it in the metal box 6 with air holes shown in Figure 2, the distance between the electrode and the infrared bulb is 20 cm, at 100 ° C The far-infrared rays act for 10 minutes to accelerate the polycondensation and curing of the carbon nanotube epoxy resin through the infrared rays.

Then, the electrode is taken out, and one end of the capillary filled with carbon nanotube epoxy resin composite material electrode body 4 is polished into a circle with sandpaper; then the hot melt adhesive 5 is melted and dropped on the copper wire lead 2 to contact with the other open end of the capillary 1 Partially fix the copper wire and seal the capillary at this end to obtain the finished product of the carbon nanotube epoxy resin composite electrode. The adhesive 5 used can be one of hot-melt glue, epoxy resin, silicone glue or 502 glue (ie α-cyanoacrylate ethyl), among which hot-melt glue is the most convenient to use.

Comparative Example 1

Same as Example 1, except that the carbon nanotube epoxy resin is cured by the oven heating method, and the oven temperature is 100° C., and it takes 6 hours to fully cure.

The carbon nanotube epoxy resin composite material that will prepare electrode remaining is coated on the glass sheet, is placed in the metal box 6 with vent hole shown in accompanying drawing 2, and the distance between electrode and infrared light bulb is 20 centimeters, at 100 ℃ far away Infrared ray for 10 minutes. It is then used for test characterization of the material.

Fig. 3 is the scanning electron micrograph (B) of the section of the carbon nanotube epoxy resin composite material electrode that embodiment 1 obtains and the scanning electron micrograph (A) of the multi-walled carbon nanotube used, and the magnification is 20000 times. It can be seen from the lower figure (B) of Figure 3 that the carbon nanotubes are dispersed in the epoxy resin body and form a good conductive network to endow the material with good conductivity; Compared with the scanning electron microscope photos of nanotubes, it can be seen that the morphology of carbon nanotube epoxy resin composites is obviously different from that of pure carbon nanotubes. Many broken ends of carbon nanotubes can be observed on the composite material section. These exposed carbon nanotubes Electrode arrays play a crucial role in the response and electrochemical catalysis of electrodes. Due to the firm bonding of carbon nanotubes with epoxy resin, it is beneficial to maintain the stability of the conductive network of carbon nanotubes, which can significantly improve the reproducibility and stability of the electrode.

FIG. 4 is a Raman spectrum diagram of the carbon nanotube epoxy resin composite electrode of Example 1. FIG. It can be seen from Figure 4 that when carbon nanotubes are composited with epoxy resin, the D, G and 2D peaks of carbon nanotubes in the composite can be observed, indicating that the structure of carbon nanotubes in the composite material is complete; in addition, the carbon nanotubes in the composite material The intensity of the 2D peak is higher than that of the D peak for CNTs, indicating the occurrence of recombination.

Fig. 5 is the carbon nanotube epoxy resin composite material electrode prepared by infrared light heating and curing in embodiment 1, and the carbon nanotube epoxy resin composite material electrode prepared by the common heating and curing method of comparative example 1. The detection concentration is 0.5mM respectively. The electrophoretic spectrum of the standard mixed solution of nicotine, rutin, chlorogenic acid and quercetin, the detection temperature is 100 °C; wherein (A) is the carbon nanotube epoxy resin composite material prepared by the common heating and curing method of comparative example 1 The detection result of the electrode; (B) is the detection result of the carbon nanotube epoxy resin composite electrode prepared by the infrared light heating and curing method in Example 1. It can be seen from Figure 5 that nicotine, rutin, chlorogenic acid and quercetin can be completely separated within 8 minutes, and the peak shape is good. The response peak currents of the four substances on the electrodes prepared by infrared heating and curing in Example 1 were significantly higher than those of the electrodes prepared by the common heating and curing method in Comparative Example 1, indicating that infrared rays can improve the sensitivity of composite electrodes; The electrical conductivity and electrocatalytic activity of the carbon nanotube network in the composite were investigated.

In order to explore and verify the application of the developed electrode in the analysis of tobacco reagent samples, the carbon nanotube epoxy resin composite electrode obtained in Example 1 was also used to analyze the tobacco sample solution. The preparation method of the tobacco sample solution is as follows: take 2.5 grams of mechanically pulverized tobacco powder, disperse it in 100 milliliters of methanol, extract it with an infrared auxiliary system for 5 minutes, and filter to obtain the extracted solution for future use. Before the analysis, draw 200 microliters of extracting solution in a glass weighing bottle with a diameter of 2 cm and a width of 2 cm, and carry out infrared solvent removal in the above-mentioned metal box 6 with air holes, which can be evaporated within three minutes. Solvent methanol, then add 1 ml of buffer to dilute and let it stand for 2 minutes before injecting and analyzing. Fig. 6 is the capillary electrophoresis spectrum of the carbon nanotube epoxy resin composite electrode obtained in Example 1 for detecting methanol extract of tobacco leaves. Different electrodes obtained by the preparation method in Example 1 were used to measure the methanol extract of the same tobacco several times, and the results were basically the same. As can be seen from Fig. 6, tobacco contains a large amount of nicotine, rutin and chlorogenic acid etc.; The carbon nanotube epoxy resin composite electrode that the preparation method of embodiment 1 obtains is illustrated simultaneously and is used for analyzing tobacco sample solution, and sensitivity High, good detection reproducibility and strong anti-pollution ability. Because the methanol extract of tobacco has complex components, other impurities do not affect the sensitivity and reproducibility of its detection.

The influence of different infrared irradiation time and temperature on the response sensitivity of nicotine to the prepared carbon nanotube epoxy resin composite electrode was also investigated. Fig. 7 shows the influence of different infrared irradiation time and temperature on the response sensitivity of the prepared carbon nanotube epoxy resin composite electrode in the detection of nicotine. It can be seen from the upper figure (A) of attached drawing 7 that when the infrared temperature is 100°C, when the infrared irradiation time increases from 4 minutes to 10 minutes, the peak current of nicotine increases from 43.4nA to 86.64nA, and the irradiation time continues to increase , The increase in sensitivity is not large, so the far-infrared radiation curing time of the electrode is selected to be 10 minutes. In addition, temperature also has an effect on the peak current of nicotine, see Figure 7 (B) below, but increasing the curing temperature has little effect on the peak current of nicotine. The optimized infrared curing condition of the present invention is infrared irradiation at 100°C for 10 minutes, and the best effect is to select infrared rays with a wavelength in the range of 3-100um.

Example 2: A carbon nanotube epoxy resin composite electrode for voltammetric analysis of tobacco chemical components and its preparation method

Different from the electrode in Example 1, the area of the working electrode used in various voltammetry analysis methods such as linear voltammetry analysis, cyclic voltammetry analysis, stripping voltammetry analysis, and differential pulse voltammetry analysis of tobacco chemical components is larger. The diameter of the circular electrode used is 1 to 6 millimeters, that is, the inner diameter of the electrode tube is required to be relatively large; at the same time, a carbon nanotube epoxy resin composite material mixture with a higher viscosity and a higher content of carbon nanotubes is used.

The preparation steps are the same as in Example 1. The difference is: weigh 1 gram of treated carbon nanotube powder and mix it with 1 gram of epoxy resin prepolymer containing curing agent, and stir thoroughly to obtain a black mixture with certain plasticity. Use one end of a hard glass tube with an outer diameter of 4 mm, an inner diameter of 2 mm, and a length of 8 cm to insert into the black mixture, so that the black mixture of carbon nanotube epoxy resin prepolymer is filled in the hard glass tube, and the filling depth is about 6 mm, and then insert a 15 cm long copper wire with a diameter of 0.3 mm into the hard glass tube through another opening until the copper wire is inserted into the black carbon nanotube epoxy resin prepolymer in the hard glass tube About 3 mm in the mixture to ensure good contact, and then placed in a metal box with air holes as shown in Figure 2, the temperature is set at 100 ° C for 10 minutes; then take out and polish one end of the hard glass tube filled with the mixture with sandpaper , into a round shape; and after melting with hot melt adhesive, drop it on the contact between the copper wire and the opening end of the hard glass tube to fix the copper wire and seal the hard glass tube to obtain carbon nanotubes for voltammetric analysis of tobacco chemical components Finished epoxy resin composite electrodes.

Comparative Example 2: Same as Example 2, except that the carbon nanotube epoxy resin composite electrode was prepared by conventional heating and curing method.

Fig. 8 is the voltammetry curves of the electrode prepared in Example 2 and the electrode prepared in Comparative Example 2 at 0.5 mM rutin, the scanning temperature is 100° C., and the scanning speed is 100 mV/s. Wherein Fig. 8 (A) is the detection result of the electrode of embodiment 2; (B) is the detection result of the electrode of comparative embodiment 2. Rutin is a common flavonoid in tobacco. It can be seen from Figure 8 that the oxidation peak current of rutin on the electrode prepared in Example 2 is two times higher than that of the electrode prepared in Comparative Example 2. times. It shows that infrared can improve the conductivity and electrocatalytic activity of carbon nanotube network in composite materials.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention also has Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. The carbon nanotube epoxy resin composite material electrode is characterized by comprising an electrode body, an electrode tube and an electrode lead; the electrode body is filled at one end of the electrode tube, and the bottom of the electrode body is round; the electrode lead is led out from the electrode body and is led out from the other end in the electrode tube; the electrode body is obtained by condensation polymerization of carbon nanotubes containing a curing agent and epoxy resin, wherein the mass of the carbon nanotubes is 10-50% of the mass of the electrode body.

2. The carbon nanotube epoxy composite electrode according to claim 1, wherein the electrode tube is made of an electrically insulating material, the electrode tube is one of a plastic tube, a ceramic tube, a quartz tube or a glass tube, and the inner diameter of the electrode tube is 25um to 8mm; the electrode lead is fixed at the other end of the electrode tube by using an adhesive, and the electrode tube at the end is sealed, wherein the adhesive is one of hot melt adhesive, epoxy resin, silicone adhesive or alpha-ethyl cyanoacrylate.

3. The carbon nanotube epoxy composite electrode of claim 1, wherein the carbon nanotubes are single-walled carbon nanotubes or multi-walled carbon nanotubes treated with nitric acid.

4. The method for preparing the carbon nanotube epoxy composite electrode according to any one of claims 1 to 3, comprising the steps of:

(1) Mixing the carbon nano tube, the epoxy resin and the curing agent according to a certain mass ratio to obtain a black viscous mixture with certain plasticity;

(2) Filling the mixture obtained in the step (1) into one end of an electrode tube, and then inserting an electrode lead into the mixture through the other end of the electrode tube;

(3) Curing the electrode tube obtained in the step (2) for a period of time at an infrared ray and a certain temperature;

(4) Polishing one end of the electrode tube solidified in the step (3) into a round shape; fixing the electrode lead at the other end of the electrode tube by using an adhesive, and sealing the end electrode tube; and obtaining the carbon nano tube epoxy resin composite material electrode.

5. The method according to claim 4, wherein the step of treating the carbon nanotubes with nitric acid in step (1) is as follows: dispersing carbon nano tubes in nitric acid, heating at 50-95 ℃ for 8-15 hours, cooling to room temperature, carrying out vacuum filtration, cleaning until the pH value of filtrate is higher than 5, and heating and drying the solid to obtain the carbon nano tubes treated by the nitric acid.

6. The method according to claim 4, wherein the carbon nanotubes of step (1) are single-walled carbon nanotubes or multi-walled carbon nanotubes; the mass of the carbon nano tube is 10-50% of the mass of the carbon nano tube, the epoxy resin and the curing agent.

7. The preparation method according to claim 4, wherein the electrode tube in the step (2) is made of an electrically insulating material, the electrode tube is one of a plastic tube, a ceramic tube, a quartz tube or a glass tube, and the inner diameter of the electrode tube is 25um-8mm; the adhesive in the step (4) is one of hot melt adhesive, epoxy resin, silicone adhesive or alpha-ethyl cyanoacrylate.

8. The method according to claim 4, wherein the infrared ray of step (3) has a wavelength of 1.40-11000um, a curing temperature of 80-120 ℃, and a curing time of 5-20min.

9. The method according to claim 8, wherein the infrared ray of step (3) has a wavelength of 3 to 100um, a curing temperature of 100 ℃ and a curing time of 10min.

10. Use of the carbon nanotube epoxy composite electrode according to any one of claims 1 to 3 for the detection of chemical components in tobacco.

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