CN110407164A - A kind of preparation method and application of carbon nanotube polymer composite membrane - Google Patents

Abstract

The invention discloses a method for preparing a carbon nanotube polymer composite film, which is characterized in that it comprises the following steps: step 1: dissolving carbon nanotubes in an organic solvent, ultrasonically dispersing, and then suction filtering to prepare a carbon nanotube film ; Step 2: SEBS is processed by hot pressing to obtain SEBS sheets; Step 3: the carbon nanotube film obtained in step 1 is placed on the surface of the SEBS sheet obtained in step 2 for hot pressing, and then ultrasonically and dried in a solvent to obtain Carbon nanotube polymer composite film. The invention has a simple preparation method, high sensitivity, good linearity, and excellent cycle stability. The invention uses a hot pressing method to infiltrate the polymer melt into carbon nanotubes, and finally obtains carbon nanotubes with good stress sensing performance. Polymer composite film.

Description

A kind of preparation method and application of carbon nanotube polymer composite film

technical field

The invention belongs to the technical field of electronic equipment, and in particular relates to a preparation method and application of a carbon nanotube polymer composite film.

Background technique

Flexible sensors, microelectronics, and artificial skin are increasingly attracting researchers' attention. Stretchable resistive strain-sensing materials have been extensively developed and used in wearable devices. The problem faced by resistive strain sensors is to achieve large strains and have good linearity under strain conditions. Conventional resistive metal strain sensors have a small measurement range because they cannot recover under large deformations. Conductive composite materials usually made by mixing conductive nanoparticles with elastomers have good sensitivity and large deformation, but there is no good linear relationship between its resistance and strain. Based on this, it is extremely important to design a strain sensor with large deformation, high sensitivity and good linear relationship.

Carbon nanotube (CNT) is a one-dimensional quantum material with a special structure mainly composed of carbon atoms arranged in a hexagonal shape. Its diameter is between 0.3 nanometers and tens of nanometers, and its length can reach several microns. Compared with steel, carbon nanotubes have only 1/6 the density of steel, but their theoretical strength is about 100 times that of steel, and they can withstand temperatures up to 3593°C, and have excellent thermal conductivity and ductility. Single-layer or multi-layer carbon nanotubes are called single-walled carbon nanotubes (SWNT) and multi-walled carbon nanotubes (MWNT). Single-walled carbon nanotubes are hollow cylinders in appearance, which are made of graphite in two dimensions. Formed by the planar curls arranged in the same way, due to the different arrangement with graphite, single-walled carbon nanotubes with different structures are formed, while the two sides of the cylinder are curved surfaces formed by the arrangement of carbon atoms in a curve. If single-walled carbon nanotubes of different structural sizes are concentrically stacked from small to large, and the distance between each adjacent layer is about 0.36 nanometers, multi-walled carbon nanotubes can be formed. Electrons in carbon nanotubes do not move freely, but are limited by quantum confinement factors. These electrons usually can only move along the axis of carbon nanotubes, and cannot move across different graphite sheets.

SEBS is a linear three-block copolymer with polystyrene as the terminal block and ethylene-butene copolymer obtained by hydrogenation of polybutadiene as the middle elastic block. SEBS does not contain unsaturated double bonds, so it has good stability and aging resistance.

Contents of the invention

The technical problem to be solved by the present invention is to provide a preparation method and application of a carbon nanotube polymer composite film.

In order to solve the above-mentioned technical problems, the invention provides a kind of preparation method of carbon nanotube polymer composite film, it is characterized in that, comprises the following steps:

Step 1: dissolving carbon nanotubes in an organic solvent, ultrasonically dispersing, and then suction filtering to prepare a carbon nanotube film;

Step 2: making SEBS sheet by hot pressing SEBS;

Step 3: Put the carbon nanotube film obtained in step 1 on the surface of the SEBS sheet obtained in step 2 for hot pressing, then ultrasonically clean in a solvent, and dry to obtain a carbon nanotube polymer composite film.

Preferably, the organic solvent in step 1 is one of ethanol, tetrahydrofuran or N-methylpyrrolidone.

Preferably, in the step 1, the solid-to-liquid ratio of the carbon nanotubes to the organic solvent is 2-10 mg/mL, the ultrasonic power is 300-500 W, and the time is 30-60 min.

Preferably, the hot pressing time in the step 2 is 5-20 minutes, the temperature is 180-210° C., and the pressure is 5-15 MPa.

Preferably, the hot pressing time in step 3 is 10-180 min, the temperature is 180-210° C., and the pressure is 4-6 MPa.

Preferably, the mass ratio of the carbon nanotube film to the SEBS sheet in the step 3 is (20-100):(3000-5000).

In the step 3, the solvent is one of water, ethanol or N-methylpyrrolidone, the drying temperature is 50-80° C., and the drying time is 1-10 hours.

The invention also provides the application of the carbon nanotube polymer composite film prepared by the above method in a strain sensor.

Compared with prior art, the beneficial effect of the present invention is:

(1) The preparation method of the present invention is simple and easy to operate. The polymer melt is permeated into the carbon nanotubes under the action of pressure by using a simple hot pressing method, and the carbon nanotubes are partially embedded in the film and partially embedded in the film surface, forming The "carpet"-like structure imparts conductivity to the film.

(2) The experimental design of the present invention is ingenious, and the thickness of the polymer melt infiltrated into the carbon nanotubes can be regulated by adjusting the hot pressing time.

(3) The carbon nanotube polymer composite film prepared by the present invention has excellent electrical conductivity, can measure large deformation, and has high sensitivity, good linear relationship and excellent cycle stability, and is suitable for stretchable strain sensing materials. The strain can reach 80%, the sensitivity factor is 18.5 under small deformation and 12.5 under large deformation, and the excellent sensing performance is maintained after 1000 cycles.

Description of drawings

Fig. 1 is the surface SEM figure of the carbon nanotube polymer composite film that embodiment 1 makes;

Fig. 2 a is the SEM figure of the carbon nanotube polymer composite film T-10 section that embodiment 1 makes;

Fig. 2 b is the SEM figure of the carbon nanotube polymer composite membrane T-30 section that embodiment 2 makes;

Fig. 2c is the SEM figure of the carbon nanotube polymer composite membrane T-60 section that embodiment 3 makes;

Fig. 3 is the response curve of the carbon nanotube polymer composite membrane T-10 relative resistance and strain that embodiment 1 makes;

Fig. 4 is the cycle stability curve of the carbon nanotube polymer composite film T-10 prepared in Example 1 under the condition of 40% strain.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

The morphology and strain sensing properties of carbon nanotube-polymer composite films were characterized by scanning electron microscopy (SEM), universal tensile machine, and digital source meter. The composite film (50×5×1 mm ³ ) was fixed using clamps with an insulating rubber layer, and the original gauge distance between the clamps was 20 mm. During the test, the electronic universal testing machine controls the tensile rate and strain range of the sample, and at the same time completes the recording of test data such as time, stress, and strain. When the composite film is strained, the electrode moves synchronously with the fixture, and at the same time, the digital multimeter records the instantaneous resistance value of the sample in situ during the stretching process.

Example 1

This embodiment provides a method for preparing a carbon nanotube polymer composite film, the specific steps are as follows:

Step 1: Take 20 mg of carbon nanotubes and dissolve them in 10 mL of N-methylpyrrolidone, sonicate in an ultrasonic machine for 1 hour, with an ultrasonic power of 500 W, to obtain a carbon nanotube dispersion, and filter the dispersion to obtain a carbon nanotube film. The carbon nanotube film is put into an oven to dry for subsequent use;

Step 2: Take 4g of SEBS, hot press at 200°C, 10MPa, 10min to get SEBS sheet;

Step 3: Put the carbon nanotube film on the SEB sheet, press it at 200°C, 4MPa, and 10min to prepare a carbon nanotube-polymer composite film, ultrasonicate the carbon nanotube-polymer composite film in ethanol for 2 hours, and then Dry in an oven at 70°C for 1 hour, and finally obtain the carbon nanotube-polymer composite film as T-10.

As shown in Figure 1, the SEM test results show that the carbon nanotubes are evenly attached to the surface of the composite film.

As shown in Figure 3, the sensor performance test shows that: T-10 has a large test range and can reach about 80% of the strain and has high sensitivity. The sensitivity factor is 18.5 in the low strain range and 12.5 in the high strain range.

As shown in Figure 4, T-10 has excellent cycle stability, and the sensing performance remains stable after 1000 cycles at 40% strain.

Example 2

The difference between this example and Example 1 is that the hot pressing time in Step 3 is changed to 30 minutes, and the rest are the same as Example 1, and the finally obtained carbon nanotube polymer composite film is marked as T-30.

Example 3

The difference between this example and example 1 is that the hot pressing time in step 3 is changed to 60 min, and the rest are the same as in example 1, and the finally obtained carbon nanotube polymer composite film is marked as T-60.

Fig. 2 a is the SEM figure of the carbon nanotube polymer composite film T-10 section that embodiment 1 makes;

Fig. 2 b is the SEM figure of the carbon nanotube polymer composite membrane T-30 section that embodiment 2 makes;

Fig. 2c is the SEM figure of the carbon nanotube polymer composite membrane T-60 section that embodiment 3 makes;

As shown in Figure 2a, Figure 2b, and Figure 2c, when the hot-pressing time increased from 10 min to 60 min, the thickness of the composite coating gradually increased from 69 μm to 198 μm.

Claims (8)

1. a kind of preparation method of carbon nanotube polymer composite membrane, which comprises the following steps:

Step 1: carbon nanotube being dissolved in organic solvent, ultrasonic disperse, then filter and carbon nano-tube film is made；

Step 2: SEBS piece is made by hot-pressing processing in SEBS；

Step 3: the carbon nano-tube film that step 1 is obtained is placed on the SEBS piece surface that step 2 obtains and carries out hot-pressing processing, then exists It is ultrasonic in solvent, it is dry, obtain carbon nanotube polymer laminated film.

2. the preparation method of carbon nanotube polymer composite membrane as described in claim 1, which is characterized in that have in the step 1 Solvent is ethyl alcohol, one of tetrahydrofuran or N-Methyl pyrrolidone.

3. the preparation method of carbon nanotube polymer composite membrane as described in claim 1, which is characterized in that carbon in the step 1 The solid-to-liquid ratio of nanotube and organic solvent is 2~10mg/mL, and ultrasonic power is 300~500W, and the time is 30~60min.

4. the preparation method of carbon nanotube polymer composite membrane as described in claim 1, which is characterized in that hot in the step 2 The pressure time is 5~20min, and temperature is 180~210 DEG C, and pressure is 5~15MPa.

5. the preparation method of carbon nanotube polymer composite membrane as described in claim 1, which is characterized in that hot in the step 3 The pressure time is 10~180min, and temperature is 180~210 DEG C, and pressure is 4~6MPa.

6. the preparation method of carbon nanotube polymer composite membrane as described in claim 1, which is characterized in that carbon in the step 3 The mass ratio of nanotube films and SEBS piece is (20~100): (3000~5000).

7. the preparation method of carbon nanotube polymer composite membrane as described in claim 1, which is characterized in that molten in the step 3 Agent is one of water, ethyl alcohol or N-Methyl pyrrolidone, and drying temperature is 50~80 DEG C, and drying time is 1~10h.

8. carbon nanotube polymer composite membrane the answering in strain transducer of any one of claim 1~7 the method preparation With.