CN105200666B - A kind of preparation method of super-hydrophobic/super-oleophilic tiny balloon shape PVDF nanofibers - Google Patents

Abstract

The invention belongs to the field of nanofiber material preparation, and in particular relates to a method for preparing superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers. The steps are as follows: (1) configure PVDF electrospinning solution, take PVDF and dissolve it in N, ‑Dimethylformamide (DMF) is configured as an electrospinning solution, and a small amount of deionized water is added dropwise to the electrospinning solution; (2) Electrospinning is performed on the above solution, and a small amount of water promotes the formation of a hollow core through a phase separation mechanism. Microspherical PVDF nanofibers. The PVDF hollow microspherical nanofibers provided by the invention are prepared by electrospinning technology, and the morphology of the nanofibers is controlled by adjusting the content of deionized water in the electrospinning solution. The invention has the advantages of low cost, simple operation and environmental friendliness, and the product has excellent hydrophobic and lipophilic effects.

Description

A preparation method of superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers

technical field

The invention belongs to the field of preparation methods of novel nanofiber materials, and in particular relates to a preparation method of superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers.

Background technique

In recent years, in the process of oil extraction, transportation and use, there are often cases of oil spills polluting the environment. In addition, the discharge of oily sewage in industry and life seriously pollutes the natural environment, so it is of great significance to develop new materials and technologies for water body oil pollution control. At present, oil-absorbing materials are mainly used to deal with marine oil pollution in my country. This method can avoid secondary pollution and can effectively recover oil spills. Commonly used oil-absorbing materials include traditional oil-absorbing materials, such as corn stalks, cotton fibers, kapok fibers, zeolites, etc.; also include new functional materials, such as resin oil-absorbing materials, carbon sponges, carbon nanotubes, and metal-organic frameworks (MOFs).

At present, the method of electrospinning to prepare nanofibers has received extensive attention. Researchers can obtain nanofibers with new functions by adjusting the microstructure of nanofibers, so as to meet the functional requirements of materials. Nanofibers prepared by electrospinning can be used as oil-absorbing materials to allow oil to enter the voids and matrix of the material, so that it has a high oil-absorbing efficiency.

Contents of the invention

The object of the present invention is to provide a method for preparing superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers with simple operation, low cost, environmentally friendly target product and strong oil absorption performance.

In order to solve the above technical problems, the present invention is achieved in this way.

A method for preparing superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers can be implemented according to the following steps.

(1) Preparation of electrospinning solution: Add deionized water to N,N-dimethylformamide (DMF), add PVDF to the solution while stirring, and finally keep stirring at 50 ^o C for 24 Hour.

(2) Preparation of the target product: Electrospinning the electrospinning solution obtained in step (1); after N,N-dimethylformamide (DMF) volatilizes and solidifies, a fiber mat is formed at the receiving end; the fiber mat is collected After drying, the target product superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers can be obtained.

As a preferred solution, in the step (2) of the present invention, the electrospinning solution obtained in the step (1) is placed in a 10-20ml medical syringe for electrospinning; the voltage of the electrospinning is 18kV, and the nozzle of the medical syringe The distance between the receiver and the receiver was 15 cm, and the flow rate of the electrospinning solution was controlled at 2.0 ml/h.

Further, in step (1) of the present invention, PVDF accounts for 5%-15% of N,N-dimethylformamide (DMF) and deionized water in terms of mass percentage.

Furthermore, in the step (2) of the present invention, in terms of mass percentage, the deionized water in the electrospinning solution accounts for 0-20% of the PVDF.

Furthermore, in the step (2) of the present invention, the content of deionized water in the electrospinning solution is 0-2.5% by mass percentage.

Furthermore, in the step (2) of the present invention, the receiver adopts a high-speed rotating drum aluminum foil receiver with a rotating speed of 500 rpm.

The present invention selects the PVDF separation material with excellent chemical stability and pollution resistance. By controlling the content of H ₂ O in PVDF/DMF/H ₂ O in the electrospinning solution, PVDF can achieve liquid-liquid phase separation in the process of electrospinning to prepare PVDF nanofibers with hollow microsphere structure. The effect of fiber surface microstructure on surface wettability was studied and applied to oil absorption experiments to obtain superhydrophobic/superlipophilic PVDF nanofiber materials.

The invention has the advantages of simple operation, low cost, environment-friendly target product and strong oil absorption performance. In the invention, non-solvent deionized water is added to the electrospinning solution to form a hollow microspherical PVDF nanofiber felt during the electrospinning process. The prepared nanofibers were respectively immersed in the lubricating oil to be tested, taken out after soaking for 1 minute, and weighed after standing for 2 minutes. Repeat the above operations until the oil absorption of the PVDF nanofiber felt sample no longer shows an increasing trend, then calculate its oil absorption.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the expression of the following content.

Figure 1-1, Figure 1-2, Figure 1-3, Figure 1-4, Figure 1-5 and Figure 1-6 are SEM images of PVDF nanofibers prepared from electrospinning solutions with different water contents according to the present invention .

Fig. 2 is the water contact angle of the PVDF nanofiber felt of the present invention.

Fig. 3 is a photograph of water droplets and oil droplets of the present invention on nanofibers.

Fig. 4 is the variation curve of PVDF nanofiber oil absorption with time in the present invention.

detailed description

The water used in the following examples is deionized water; the reagents used are of analytical grade unless otherwise specified; in the examples, the SEM picture of the PVDF nanofiber oil-absorbing material made is scanned by the Hitachi S-3500N type Obtained by electron microscope scanning; in the present invention, a video microscope is used to study the contact angle between the surface of the nanofiber and water and take photos of water droplets for measurement and photography. Fig. 1 is the SEM picture of the PVDF nanofiber that the electrospinning solution of different water content of the present invention makes; Wherein, A: 0.0%, B: 0.5%, C: 1.0%, D: 1.5%, E: 2.0% , F: 2.5%.

Example 1.

Weigh 3g of PVDF powder, slowly add it into 18g of DMF under magnetic stirring, and then place it in a water bath at 50°C for 24h with magnetic stirring to form an electrospinning solution. The solution was cooled to room temperature before electrospinning. The above electrospinning solution was placed in a 20ml plastic syringe equipped with a 0.5mm diameter stainless steel needle. The voltage of electrospinning is 18kV, the distance between the nozzle and the receiver is 15cm, the advancing speed of the syringe is 2ml/h, and the humidity in the box is 50%. During the electrospinning process, solidification occurs due to the volatilization of the volatile solvent DMF, and a layer of PVDF fiber mat is formed on the aluminum foil. The PVDF fiber felt was collected and dried in a vacuum oven at 50 ^o C for 24 hours to obtain hollow microspherical PVDF nanofibers. Weigh 0.5g of the PVDF nanofiber felt sample and place it in a stainless steel dense mesh basket. Then fully immerse it in the lubricating oil to be tested. After soaking for 1 minute, take out the small basket containing the PVDF nanofiber felt, and place it on an electronic balance to measure the weight after it has stood still for 2 minutes. Repeat the above operations until the oil absorption of the PVDF nanofiber felt sample no longer shows an increasing trend, then calculate its oil absorption. The oil absorption rate of PVDF nanofiber mat can be calculated using the following formula: , where m ₀ is the original mass of PVDF nanofiber felt, and m _t is its mass after oil absorption for a period of time. The oil absorption of the nanofibers reached the optimum value of 11.76 g/g at 2 minutes, and then basically reached the oil absorption equilibrium (see Figure 4).

Example 2.

Weigh 3g of PVDF powder, slowly add it into a mixed solution of 18g DMF and 0.1g deionized water under magnetic stirring, and then place it in a 50°C water bath with magnetic stirring for 24h to form an electrospinning solution. The solution was cooled to room temperature before electrospinning. The above electrospinning solution was placed in a 20ml plastic syringe equipped with a 0.5mm diameter stainless steel needle. The voltage of electrospinning is 18kV, the distance between the nozzle and the receiver is 15cm, the advancing speed of the syringe is 2ml/h, and the humidity in the box is 50%. During the electrospinning process, solidification occurs due to the volatilization of the volatile solvent DMF, and a layer of PVDF fiber mat is formed on the aluminum foil. The PVDF fiber felt was collected and dried in a vacuum oven at 50 ^o C for 24 hours to obtain hollow microspherical PVDF nanofibers. Weigh 0.5g of the PVDF nanofiber felt sample and place it in a stainless steel dense mesh basket. Then fully immerse it in the lubricating oil to be tested. After soaking for 1 minute, take out the small basket containing the PVDF nanofiber felt, and place it on an electronic balance to measure the weight after it has stood still for 2 minutes. Repeat the above operations until the oil absorption of the PVDF nanofiber felt sample no longer shows an increasing trend, then calculate its oil absorption. The oil absorption rate of PVDF nanofiber mat can be calculated using the following formula: , where m ₀ is the original mass of PVDF nanofiber felt, and m _t is its mass after oil absorption for a period of time. The oil absorption of nanofibers reaches the optimum value of 14.9g/g in 5 minutes, and then basically reaches the oil absorption balance (see Figure 4).

Example 3.

Weigh 3g of PVDF powder, slowly add it into a mixed solution of 18g DMF and 0.2g deionized water under magnetic stirring, and then place it in a water bath at 50°C for 24h with magnetic stirring to form an electrospinning solution. The solution was cooled to room temperature before electrospinning. The above electrospinning solution was placed in a 20ml plastic syringe equipped with a 0.5mm diameter stainless steel needle. The voltage of electrospinning is 18kV, the distance between the nozzle and the receiver is 15cm, the advancing speed of the syringe is 2ml/h, and the humidity in the box is 50%. During the electrospinning process, solidification occurs due to the volatilization of the volatile solvent DMF, and a layer of PVDF fiber mat is formed on the aluminum foil. The PVDF fiber felt was collected and dried in a vacuum oven at 50 ^o C for 24 hours to obtain hollow microspherical PVDF nanofibers. Weigh 0.5g of the PVDF nanofiber felt sample and place it in a stainless steel dense mesh basket. Then fully immerse it in the lubricating oil to be tested. After soaking for 1 minute, take out the small basket containing the PVDF nanofiber felt, and place it on an electronic balance to measure the weight after it has stood still for 2 minutes. Repeat the above operations until the oil absorption of the PVDF nanofiber felt sample no longer shows an increasing trend, then calculate its oil absorption. The oil absorption rate of PVDF nanofiber felt can be calculated using the following formula: , where m ₀ is the original mass of PVDF nanofiber felt, and m _t is its mass after oil absorption for a period of time. The oil absorption of nanofibers reached the optimum value of 15.7g/g at 7 minutes, and then basically reached the oil absorption equilibrium (see Figure 4).

Example 4.

Weigh 3g of PVDF powder, slowly add it into a mixed solution of 18g DMF and 0.3g deionized water under magnetic stirring, and then place it in a water bath at 50°C for 24h with magnetic stirring to form an electrospinning solution. The solution was cooled to room temperature before electrospinning. The above electrospinning solution was placed in a 20ml plastic syringe equipped with a 0.5mm diameter stainless steel needle. The voltage of electrospinning is 18kV, the distance between the nozzle and the receiver is 15cm, the advancing speed of the syringe is 2ml/h, and the humidity in the box is 50%. During the electrospinning process, solidification occurs due to the volatilization of the volatile solvent DMF, and a layer of PVDF fiber mat is formed on the aluminum foil. The PVDF fiber felt was collected and dried in a vacuum oven at 50 ^o C for 24 hours to obtain hollow microspherical PVDF nanofibers. Weigh 0.5g of the PVDF nanofiber felt sample and place it in a stainless steel dense mesh basket. Then fully immerse it in the lubricating oil to be tested. After soaking for 1 minute, take out the small basket containing the PVDF nanofiber felt, and place it on an electronic balance to measure the weight after it has stood still for 2 minutes. Repeat the above operations until the oil absorption of the PVDF nanofiber felt sample no longer shows an increasing trend, then calculate its oil absorption. The oil absorption rate of PVDF nanofiber mat can be calculated using the following formula: , where m ₀ is the original mass of PVDF nanofiber felt, and m _t is its mass after oil absorption for a period of time. The oil absorption of nanofibers reached the optimum value of 17.08g/g at 6 minutes, and then basically reached the oil absorption balance (see Figure 4).

Example 5.

Weigh 3g of PVDF powder, slowly add it into a mixed solution of 18g DMF and 0.4g deionized water under magnetic stirring, and then place it in a 50°C water bath with magnetic stirring for 24h to form an electrospinning solution. The solution was cooled to room temperature before electrospinning. The above electrospinning solution was placed in a 20ml plastic syringe equipped with a 0.5mm diameter stainless steel needle. The voltage of electrospinning is 18kV, the distance between the nozzle and the receiver is 15cm, the advancing speed of the syringe is 2ml/h, and the humidity in the box is 50%. During the electrospinning process, solidification occurs due to the volatilization of the volatile solvent DMF, and a layer of PVDF fiber mat is formed on the aluminum foil. The PVDF fiber felt was collected and dried in a vacuum oven at 50 ^o C for 24 hours to obtain hollow microspherical PVDF nanofibers. Weigh 0.5g of the PVDF nanofiber felt sample and place it in a stainless steel dense mesh basket. Then fully immerse it in the lubricating oil to be tested. After soaking for 1 minute, take out the small basket containing the PVDF nanofiber felt, and place it on an electronic balance to measure the weight after it has stood still for 2 minutes. Repeat the above operations until the oil absorption of the PVDF nanofiber felt sample no longer shows an increasing trend, then calculate its oil absorption. The oil absorption rate of PVDF nanofiber mat can be calculated using the following formula: , where m ₀ is the original mass of PVDF nanofiber felt, and m _t is its mass after oil absorption for a period of time. The oil absorption of nanofibers reached the optimum value of 17.36g/g at 7 minutes, and then basically reached the oil absorption balance (see Figure 4).

Example 6.

Weigh 3g of PVDF powder, slowly add it into a mixed solution of 18g DMF and 0.5g deionized water under magnetic stirring, and then place it in a water bath at 50°C for 24h with magnetic stirring to form an electrospinning solution. The solution was cooled to room temperature before electrospinning. The above electrospinning solution was placed in a 20ml plastic syringe equipped with a 0.5mm diameter stainless steel needle. The voltage of electrospinning is 18kV, the distance between the nozzle and the receiver is 15cm, the advancing speed of the syringe is 2ml/h, and the humidity in the box is 50%. During the electrospinning process, solidification occurs due to the volatilization of the volatile solvent DMF, and a layer of PVDF fiber mat is formed on the aluminum foil. The PVDF fiber felt was collected and dried in a vacuum oven at 50 ^o C for 24 hours to obtain hollow microspherical PVDF nanofibers. Weigh 0.5g of the PVDF nanofiber felt sample and place it in a stainless steel dense mesh basket. Then fully immerse it in the lubricating oil to be tested. After soaking for 1 minute, take out the small basket containing the PVDF nanofiber felt, and place it on an electronic balance to measure the weight after it has stood still for 2 minutes. Repeat the above operations until the oil absorption of the PVDF nanofiber felt sample no longer shows an increasing trend, then calculate its oil absorption. The oil absorption rate of PVDF nanofiber mat can be calculated using the following formula: , where m ₀ is the original mass of PVDF nanofiber felt, and m _t is its mass after oil absorption for a period of time. The oil absorption of nanofibers reached the optimum value of 21.48g/g at 6 minutes, and then basically reached the oil absorption equilibrium (see Figure 4).

Claims (4)

1. a preparation method of superhydrophobic/super-oleophilic hollow microspherical PVDF nanofiber, is characterized in that, implements as follows: (1) Preparation of electrospinning solution: Add deionized water to N,N-dimethylformamide (DMF), add PVDF to the solution while stirring, and finally keep stirring at 50 ^o C for 24 hours; the ratio of deionized water to PVDF is 0.1-0.5:3; (2) Preparation of the target product: Electrospinning the electrospinning solution obtained in step (1); N,N-dimethylformamide (DMF) and a small amount of deionized water are volatilized and solidified together to form a fiber mat at the receiving end; The fiber mat is collected and then dried to obtain the target product superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers. 2. The method for preparing superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers according to claim 1, characterized in that: in the step (2), the electrospinning solution obtained in the step (1) is placed at 10- Electrospinning was carried out in a 20ml medical syringe; the electrospinning voltage was 18kV, the distance between the nozzle of the medical syringe and the receiver was 15cm, and the flow rate of the electrospinning solution was controlled at 2.0ml/h. 3. The method for preparing superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers according to claim 2, characterized in that: in the step (1), in terms of mass percentage, PVDF accounts for N, N-di Methylformamide (DMF) and take 5%~15% of deionized water. 4. The method for preparing superhydrophobic/superoleophilic hollow microspherical PVDF nanofibers according to claim 3, characterized in that: in the step (2), the receiver adopts a high-speed rotating drum aluminum foil receiver with a rotating speed of 500 rpm /min.