CN110616484A - Method for preparing piezoelectric PVDF (polyvinylidene fluoride) coated carbon fiber by electrostatic spinning technology - Google Patents

Abstract

The invention discloses a method for preparing piezoelectric PVDF (polyvinylidene fluoride) -coated carbon fibers by using an electrostatic spinning technology, which comprises the steps of firstly, mixing polyvinylidene fluoride (PVDF) and N, N-Dimethylformamide (DMF) to prepare a spinning solution; and then coating polyvinylidene fluoride (PVDF) on the surface of the carbon fiber by utilizing an electrostatic spinning technology to prepare the carbon fiber-PVDF piezoelectric core-spun yarn. The carbon fiber-PVDF piezoelectric core-spun yarn prepared by the electrostatic spinning technology can be more conveniently applied to piezoelectric fabrics.

Description

A method for preparing piezoelectric PVDF-coated carbon fibers by electrospinning technology

technical field

The invention relates to a method for preparing piezoelectric PVDF-coated carbon fibers by electrostatic spinning technology, and belongs to the field of flexible piezoelectric materials.

Background technique

Piezoelectric fiber is a functional material that converts mechanical energy and electrical energy. Piezoelectric material refers to the material that changes the corresponding induced charge due to the change of static pressure. Most of the piezoelectric materials studied at present are in the form of films or blocks, and piezoelectric fibers, as a special form of piezoelectric materials, are more and more widely used. As a piezoelectric material, polyvinylidene fluoride (PVDF) has a strong piezoelectric effect and is currently the most systematic and widely used polymer in piezoelectric polymer materials. Compared with the currently commonly used polymers (such as quartz and piezoelectric ceramics), it also has the advantages of small acoustic impedance, wide frequency response, small dielectric constant, strong impact resistance, and easy processing into arbitrary shapes.

With the continuous development of science and technology, the traditional method of preparing PVDF piezoelectric film technology has been very mature, because the electrospinning technology has the advantages of simple operation and low cost, so the use of electrospinning to spin PVDF piezoelectric film is currently widely respected. s method. Yarns with piezoelectric properties are prepared by electrospinning technology, which can be more conveniently applied to fabrics, so the present invention provides a method for preparing piezoelectric PVDF-coated carbon fibers by electrospinning technology. Since carbon fiber is a high-strength, high-modulus new fiber material with a carbon content of more than 95%, it has good electrical conductivity, so it can be used as a core yarn, and the core is prepared by combining electrospinning technology with piezoelectric PVDF yarn.

Contents of the invention

The invention utilizes the good electrical conductivity of the carbon fiber to derive the piezoelectric signal generated by PVDF, and at the same time, the electrospinning technology has simple equipment, low cost and simple operation. Based on the above conditions, the present invention provides a method for preparing piezoelectric PVDF-coated carbon fibers with electrospinning technology, which specifically includes the following steps:

1) Wash the reaction vessel and magneton with deionized water and dry them, and mix polyvinylidene fluoride (PVDF) and solvent N,N-dimethylformamide (DMF) as the spinning solution solute in the reaction vessel Putting magnets into the mixed solution to seal the mixed solution, placing the sealed reaction vessel in a water bath for slow heating, stirring with a magnetic stirring device, and then standing for cooling to obtain a spinning solution;

2) Extract the spinning solution obtained in step 1) with a syringe, fix the syringe in the syringe pump, adjust the electrospinning parameters, connect the spinneret to the positive and negative electrodes of high voltage voltage respectively, and the solution will flow under the action of the electric field force. The apex of the Taylor cone of the spinneret is accelerated, and finally the surface tension is overcome by a sufficiently large electric field force to spray fine streams, and the fine streams form fiber webs at the bell mouth. At the same time, after the carbon fiber passes through the bell mouth, it is pulled out from the PVDF fiber net by the winding roller, so that the piezoelectric PVDF is evenly coated on the carbon fiber through the rotating bell mouth and finally collected by the winding roller to obtain a carbon fiber as the core yarn. , Piezoelectric PVDF-coated core-spun yarn;

3) Put the core-spun yarn prepared in step 2) into an oven to dry, and finally obtain the carbon fiber-PVDF piezoelectric core-spun yarn.

Further, the temperature of the water bath is 60°C-80°C, the magnetic stirring time is 4h-5h, and the concentration of PVDF in the spinning solution is 8%-12%.

Further, the electrospinning parameters are as follows: the extrusion speed of the spinning solution is 0.3ml/h-0.7ml/h, the spinning distance is 6cm-10cm, the distance between the two needles is 10cm-15cm, and the spinning voltage is 4KV-5KV, The rotation speed of the winding roller is 0.02mm/s-0.2mm/s, the rotation speed of the bell mouth is 300rpm-800rpm, the temperature of the electrospinning environment is 20±2°C, and the relative humidity is 60±5%.

Further, the drying temperature is 80°C-100°C, and the drying time is 2h-5h.

The invention is a method for preparing piezoelectric PVDF-coated carbon fiber by electrospinning technology, which has the following beneficial effects:

(1) The electrospinning technology used in this method has simple equipment, low cost, and simple operation, and the electrospinning process itself has a polarization effect, eliminating the need for subsequent polarization steps.

(2) Carbon fiber has good mechanical properties and electrical conductivity. Using it as a core yarn can give full play to its mechanical properties and export the piezoelectric signal generated by PVDF.

(3) Compared with most current PVDF piezoelectric films prepared by electrospinning technology, the present invention uses electrospinning technology to prepare carbon fiber-PVDF piezoelectric yarns, which can be more conveniently applied to the weaving of piezoelectric fabrics .

Description of drawings

Fig. 1 is a device schematic diagram of a carbon fiber-PVDF piezoelectric core-spun yarn preparation device.

Fig. 2 is a surface SEM image of a carbon fiber-PVDF piezoelectric core-spun yarn shown in Example 3.

Fig. 3 is a cross-sectional SEM diagram of a carbon fiber-PVDF piezoelectric core-spun yarn shown in Example 3,

Fig. 4 is a graph showing the piezoelectric voltage test results of a carbon fiber-PVDF piezoelectric core-spun yarn shown in Example 3.

In the accompanying drawings, the parts represented by each label are as follows:

1. Carbon fiber, 2. Bell mouth, 3. Injection needle, 4. Fiber mesh, 5. Core-spun yarn, 6. Winding roller, 7. PVDF, 8. Carbon fiber.

Detailed ways

In order to make the technical solution of the present invention clearer, the present invention will be further described in detail below in conjunction with the examples.

Embodiment one

1) Wash the reaction vessel and the magnetron with deionized water and dry them, weigh 0.8 g of polyvinylidene fluoride (PVDF) and 9.2 g of N,N-dimethylformamide (DMF) and mix them, and put them into the mixed solution After adding the magnet, seal the mixed solution, place the sealed reaction vessel in a water bath and heat slowly to 70°C, stir with a magnetic stirring device for 5 hours, then let it stand and cool to room temperature to obtain spinning solution;

2) Extract the spinning solution obtained in step 1) with a syringe, use carbon fiber as the core yarn, and prepare carbon fiber-PVDF piezoelectric core-spun yarn by electrospinning. The extrusion speed of the spinning solution is 0.5ml/h, and the spinning The distance between the two needles is 8cm, the distance between the two needles is 12cm, the spinning voltage is 4.5KV, the speed of the winding roller is 0.05mm/s, the speed of the bell mouth is 500rpm, the temperature of the electrospinning environment is 20±2℃, and the relative humidity is 60± 5%;

3) Put the carbon fiber-PVDF piezoelectric core-spun yarn prepared in step 2) into an oven for drying at a drying temperature of 80° C. and a drying time of 3 hours to finally obtain a carbon fiber-PVDF piezoelectric core-spun yarn.

Embodiment two

1) Wash the reaction vessel and the magnetron with deionized water and dry them, weigh 0.8 g of polyvinylidene fluoride (PVDF) and 9.2 g of N,N-dimethylformamide (DMF) and mix them, and put them into the mixed solution After adding the magnet, seal the mixed solution, place the sealed reaction vessel in a water bath and heat slowly to 70°C, stir with a magnetic stirring device for 5 hours, then let it stand and cool to room temperature to obtain spinning solution;

2) Extract the spinning solution obtained in step 1) with a syringe, use carbon fiber as the core yarn, and prepare carbon fiber-PVDF piezoelectric core-spun yarn by electrospinning. The extrusion speed of the spinning solution is 0.5ml/h, and the spinning The distance between the two needles is 8cm, the distance between the two needles is 12cm, the spinning voltage is 4.5KV, the speed of the winding roller is 0.2mm/s, the speed of the bell mouth is 500rpm, the temperature of the electrospinning environment is 20±2℃, and the relative humidity is 60± 5%;

3) Put the carbon fiber-PVDF piezoelectric core-spun yarn prepared in step 2) into an oven for drying at a drying temperature of 80° C. and a drying time of 3 hours to finally obtain a carbon fiber-PVDF piezoelectric core-spun yarn.

Embodiment Three

1) Wash the reaction vessel and magnetron with deionized water and dry them, weigh 1 gram of polyvinylidene fluoride (PVDF) and 9 grams of N,N-dimethylformamide (DMF) and mix them, and put them into the mixed solution After adding the magnet, seal the mixed solution, place the sealed reaction vessel in a water bath and heat slowly to 70°C, stir with a magnetic stirring device for 5 hours, then let it stand and cool to room temperature to obtain spinning solution;

2) Extract the spinning solution obtained in step 1) with a syringe, use carbon fiber as the core yarn, and prepare carbon fiber-PVDF piezoelectric core-spun yarn by electrospinning. The extrusion speed of the spinning solution is 0.5ml/h, and the spinning The distance between the two needles is 8cm, the distance between the two needles is 12cm, the spinning voltage is 4.5KV, the speed of the winding roller is 0.05mm/s, the speed of the bell mouth is 500rpm, the temperature of the electrospinning environment is 20±2℃, and the relative humidity is 60± 5%;

3) Put the carbon fiber-PVDF piezoelectric core-spun yarn prepared in step 2) into an oven for drying at a drying temperature of 80° C. and a drying time of 3 hours to finally obtain a carbon fiber-PVDF piezoelectric core-spun yarn.

Embodiment four

1) Wash the reaction vessel and magnetron with deionized water and dry them, weigh 1 gram of polyvinylidene fluoride (PVDF) and 9 grams of N,N-dimethylformamide (DMF) and mix them, and put them into the mixed solution After adding the magnet, seal the mixed solution, place the sealed reaction vessel in a water bath and heat slowly to 70°C, stir with a magnetic stirring device for 5 hours, then let it stand and cool to room temperature to obtain spinning solution;

2) Extract the spinning solution obtained in step 1) with a syringe, use carbon fiber as the core yarn, and prepare carbon fiber-PVDF piezoelectric core-spun yarn by electrospinning. The extrusion speed of the spinning solution is 0.5ml/h, and the spinning The distance between the two needles is 8cm, the distance between the two needles is 12cm, the spinning voltage is 4.5KV, the speed of the winding roller is 0.2mm/s, the speed of the bell mouth is 500rpm, the temperature of the electrospinning environment is 20±2℃, and the relative humidity is 60± 5%;

3) Put the carbon fiber-PVDF piezoelectric core-spun yarn prepared in step 2) into an oven for drying at a drying temperature of 80° C. and a drying time of 3 hours to finally obtain a carbon fiber-PVDF piezoelectric core-spun yarn.

Embodiment five

1) Wash the reaction vessel and magnetron with deionized water and dry them, weigh 1.2 grams of polyvinylidene fluoride (PVDF) and 8.8 grams of N,N-dimethylformamide (DMF) and mix them, and put them into the mixed solution After adding the magnet, seal the mixed solution, place the sealed reaction vessel in a water bath and heat slowly to 70°C, stir with a magnetic stirring device for 5 hours, then let it stand and cool to room temperature to obtain spinning solution;

2) Extract the spinning solution obtained in step 1) with a syringe, use carbon fiber as the core yarn, and prepare carbon fiber-PVDF piezoelectric core-spun yarn by electrospinning. The extrusion speed of the spinning solution is 0.5ml/h, and the spinning The distance between the two needles is 8cm, the distance between the two needles is 12cm, the spinning voltage is 4.5KV, the speed of the winding roller is 0.05mm/s, the speed of the bell mouth is 500rpm, the temperature of the electrospinning environment is 20±2℃, and the relative humidity is 60± 5%;

3) Put the carbon fiber-PVDF piezoelectric core-spun yarn prepared in step 2) into an oven for drying at a drying temperature of 80° C. and a drying time of 3 hours to finally obtain a carbon fiber-PVDF piezoelectric core-spun yarn.

Embodiment six

1) Wash the reaction vessel and magnetron with deionized water and dry them, weigh 1.2 grams of polyvinylidene fluoride (PVDF) and 8.8 grams of N,N-dimethylformamide (DMF) and mix them, put them into the mixed solution After adding the magnet, seal the mixed solution, place the sealed reaction vessel in a water bath and heat slowly to 70°C, stir with a magnet stirring device for 5 hours, then let it stand and cool to room temperature to obtain spinning solution;

2) Extract the spinning solution obtained in step 1) with a syringe, use the carbon fiber as the core yarn, and prepare the carbon fiber-PVDF piezoelectric core-spun yarn by electrospinning, the extrusion speed of the spinning solution is 0.5ml/h, and the spinning The distance between the two needles is 8cm, the distance between the two needles is 12cm, the spinning voltage is 4.5KV, the speed of the winding roller is 0.2mm/s, the speed of the bell mouth is 500rpm, the temperature of the electrospinning environment is 20±2℃, and the relative humidity is 60± 5%;

3) Put the carbon fiber-PVDF piezoelectric core-spun yarn prepared in step 2) into an oven for drying at a drying temperature of 80° C. and a drying time of 3 hours to finally obtain a carbon fiber-PVDF piezoelectric core-spun yarn.

Table 1: embodiment one to six core-spun yarn performance detection results

Example Core yarn piezoelectric range Core yarn performance Embodiment one -6.5v-6.5v Moderate PVDF coating, better evenness Embodiment two -4.5v-4.5v Thin PVDF coating, moderate evenness Embodiment Three -10v-10v The PVDF coating is thicker, and the evenness is better Embodiment four -7v-7v Thin PVDF coating, moderate evenness Embodiment five -8.5v-8.5v Thick PVDF coating, moderate evenness Embodiment six -6v-6v Moderate PVDF coating, poor evenness

The above descriptions are only individual embodiments of the present invention, and are not limited to the present invention. All equal modifications, equivalent replacements and improvements made within the principles of the present invention should be included in the scope of the patent of the present invention. within range.

Claims (4)

1. A method for preparing piezoelectric PVDF (polyvinylidene fluoride) coated carbon fibers by using an electrostatic spinning technology sequentially comprises the following steps:

1) cleaning a reaction vessel and magnetons with deionized water, drying, mixing polyvinylidene fluoride (PVDF) serving as a spinning solution solute and N, N-Dimethylformamide (DMF) serving as a solvent in the reaction vessel, adding the magnetons into the mixed solution to seal the mixed solution, slowly heating the sealed reaction vessel in a water bath kettle, stirring by using a magneton stirring device, and then standing and cooling to obtain a spinning solution;

2) extracting the spinning solution obtained in the step 1) by using an injector, fixing the injector in an injection pump, adjusting electrostatic spinning parameters, connecting a spinning nozzle with a high-voltage positive electrode and a high-voltage negative electrode respectively, accelerating the solution at the top point of a Taylor cone of the spinning nozzle under the action of an electric field force, and finally overcoming surface tension through enough electric field force to spray a trickle, wherein the trickle forms a fiber net at a horn mouth. Meanwhile, after the carbon fiber passes through the bell mouth, the carbon fiber is pulled out from the PVDF fiber net by the winding roller, so that the piezoelectric PVDF is uniformly coated on the carbon fiber through the rotary bell mouth and finally collected by the winding roller, and the core-spun yarn which takes the carbon fiber as the core yarn and is coated by the piezoelectric PVDF is obtained;

3) putting the core-spun yarn prepared in the step 2) into an oven for drying, and finally obtaining the carbon fiber-PVDF piezoelectric core-spun yarn.

2. The method for preparing the piezoelectric PVDF-coated carbon fiber by the electrostatic spinning technology as claimed in claim 1, wherein the temperature of the water bath kettle is 60-80 ℃, the stirring time of the magnetons is 4-5 h, and the concentration of PVDF in the spinning solution is 8-12%.

3. The method for preparing piezoelectric PVDF-coated carbon fiber by electrospinning technique according to claim 1, wherein the electrospinning parameters are as follows: the extrusion speed of the spinning solution is 0.3 ml/h-0.7 ml/h, the spinning distance is 6 cm-10 cm, the distance of double needles is 10 cm-15 cm, the spinning voltage is 4 KV-5 KV, the rotating speed of a winding roller is 0.02 mm/s-0.2 mm/s, the rotating speed of a bell mouth is 300 rpm-800 rpm, the ambient temperature of electrostatic spinning is 20 +/-2 ℃, and the relative humidity is 60 +/-5%.

4. The method for preparing the piezoelectric PVDF-coated carbon fiber by the electrospinning technology according to claim 1, wherein the drying temperature is 80-100 ℃, and the drying time is 2-5 h.