CN103706182A - Spherical and linear combined compound fiber air filtering material and preparation method thereof - Google Patents

Abstract

The invention discloses a spherical and linear combined compound fiber air filtering material and a preparation method thereof. The spherical and linear combined compound fiber air filtering material comprises interlace-arranged electro-spun polysulfone fibers and silica nano-particles inlaid on the surfaces of the electro-spun polysulfone fibers. The preparation method comprises the following steps: adding the silica nano-particles into a polysulfone spinning liquid having a mass fraction of 15-25% to obtain a composite spinning liquid, and collecting electro-spun polysulfone fibers with the surfaces inlaid with the silica nano-particles on the surface of aluminum foil of a receiving roller through an electro-spinning machine having a plurality of parallel nozzles to obtain the spherical and linear combined compound fiber air filtering material. The spherical and linear combined compound fiber air filtering material has a high filtering efficiency on dusts in air, and a low pressure drop.

Description

A ball-and-string combined composite fiber air filter material and its preparation method

technical field

The invention relates to an air filter material, in particular to a ball-string composite fiber air filter material and a preparation method thereof.

Background technique

Dust in the air is one of the main sources of pollution, especially in industrial areas and public social places. : The ultra-clean room of the microelectronics workshop and the air purification of the optical engineering workshop are also essential. Air filtration is usually used to reduce dust in the air. Air filtration is an operation to separate and capture particles dispersed in the air. Electrospinning can be used to obtain nanoscale fibers with a diameter of tens or hundreds of nanometers. The porous fiber membrane formed by the fiber has a large specific surface area and a high porosity of the membrane, which is very suitable for use as a filter material. At present, most of the research on electrospun nanofiber air filter materials is based on traditional filter media, and nanofibers are directly deposited on the base cloth to form a composite filter material composed of nanofiber layers and traditional filter media. Leung found that laminating microfiber mats on the surface of nanofiber mats can increase filtration efficiency, and the pressure drop is smaller than that of pure nanofiber mats. Shin et al. prepared a glass fiber/nanofiber composite filter material. Adding a small amount of nanofiber can improve the collection efficiency of the glass fiber filter material, but the pressure drop will also increase. Qin et al. spread nanofibers of different surface densities on spunbond and meltblown nonwovens. After the nanofibers were spun on the nonwoven base fabric, the filtration efficiency was improved, but the pressure drop also increased significantly. Agne et al. composited PVA nanofiber membranes with polypropylene nonwovens. As the thickness of the nanofiber membranes increased, the filtration efficiency gradually increased. Patanaik, Leung, etc. covered polyethylene oxide (PEO) nanofibers on a nonwoven substrate to form a composite filter material. Wang et al. first electrospun a polyacrylonitrile (PAN) fiber layer and then covered it with PVA nanofibers to form a composite filter material. Vitchuli et al. deposited polyamide 66 nanofibers on a 50/50 polyamide 6/cotton nonwoven fabric substrate, and the filtration efficiency increased when the fiber packing density increased. The above research is to combine single-diameter electrospun nanofibers with ordinary non-woven fabrics to form an air filter material. Although the filtration efficiency has improved, the pressure drop during the filtration process has also increased. Currently, the filtration efficiency is 30%. 2.4g/m is covered on the melt-blown nonwoven fabric with a drop of 35Pa ² After using nanofibers, the filtration efficiency can reach more than 99.9%, but the pressure drop also reaches 1530Pa. How to prepare high-efficiency and low-resistance nanofiber composites by electrospinning has become one of the focuses in the field of filtration materials.

Contents of the invention

The purpose of the present invention is to provide a ball-and-string composite fiber air filter material with high filtration efficiency, small pressure drop, high efficiency and low resistance and a preparation method thereof.

The technical solution of the present invention is: a composite fiber air filter material with ball and thread combination, which includes electrospun polysulfone fibers arranged in a staggered manner and silicon dioxide nanometer microspheres embedded on the surface of the electrospun polysulfone fibers.

Further, the diameter of the electrospun polysulfone fiber is 500-2200 nm, and the diameter of the silica nanosphere is 300-900 nm.

Further, the porosity of the ball-and-wire combined composite fiber air filter material is 80-87%, the average pore size is 0.5 μm-6.5 μm, the filtration efficiency of NaCl aerosol with a median diameter of 75 nm is 99-99.99%, and the pressure drop It is 150~500Pa.

The preparation method of the above-mentioned ball-string composite fiber air filter material comprises the following steps:

1) Prepare a polysulfone spinning solution with a mass fraction of 15%~25%, and then add silica nanospheres to the polysulfone spinning solution. The mass of the silica nanospheres is the polysulfone spinning solution. 0.5%~6% of the liquid mass, and then use a constant temperature magnetic stirrer to stir evenly at room temperature to obtain a composite spinning solution;

2) Pour the composite spinning liquid into several injection syringes, and then put the several injection syringes into the multi-nozzle electrospinning machine in turn, connect each nozzle with copper bars, and then connect the high-voltage DC power supply The anode is connected to the copper strip, the negative electrode is connected to the metal receiving drum and grounded, the multi-nozzle electrospinning machine is started, and the electrospun polysulfone fiber is collected on the aluminum foil surface of the receiving drum with silica nanospheres embedded on the surface;

3) After spinning, a layer of electrospun fiber membrane is formed on the surface of the aluminum foil, and it is placed at room temperature for 24 to 72 hours until the solvent is fully evaporated, and then the electrospun fiber membrane is peeled off from the surface of the aluminum foil, and then heated at 190°C Under heat treatment for 60-180 minutes, a ball-and-string combined composite fiber air filter material with stable structure and performance is obtained.

Further, the solvent of the polysulfone spinning solution is a mixed solution of dimethylformamide and acetone, and the mass ratio of the dimethylformamide to the acetone is 9:1.

Further, when the multi-nozzle electrospinning machine is working, the spinning voltage is 15-30kV, the spinning distance is 10-20cm, the spinning liquid flow rate is 1.0-2.5mL/h, and the cylinder traverse distance is 10-25cm, The traverse speed of the syringe is 10~30cm/min.

The advantages of the present invention are: the ball-and-wire composite fiber air filter material is composed of fibers with a diameter of hundreds of nanometers or 1-2 microns and nano-scale microspheres, and the microspheres on the surface of the fibers can increase the specific surface area of the material , Reduce the pores between the fibers, thereby increasing the ability to absorb and intercept dust in the air, so that the composite filter material has a high filtration rate and low pressure drop, effectively overcoming the existing electrostatic spinning fiber and non-woven Although the composite filter material made of cloth has high filtration efficiency, it has the disadvantage of large pressure drop.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Fig. 1 is the scanning electron micrograph of the ball wire combination type composite fiber air filter material of embodiment one;

Fig. 2 is the scanning electron micrograph of the ball and wire combination type composite fiber air filter material of embodiment two;

Fig. 3 is the scanning electron micrograph of the ball and wire combination type composite fiber air filter material of embodiment three;

Fig. 4 is a scanning electron microscope image of the ball-and-wire combined composite fiber air filter material of Example 4.

Detailed ways

Example 1: Weigh 5g of polysulfone particles with an electronic balance and dissolve them in 20g of a mixed solution of dimethylformamide and acetone with a mass ratio of 9:1, and stir at room temperature with a constant temperature magnetic stirrer to accelerate dissolution, and prepare Obtaining a polysulfone spinning solution with a mass percentage of 20%; taking by weighing 1.5g of silicon dioxide nano-microspheres with an electronic balance, adding in the above-mentioned 25g polysulfone spinning solution, and stirring evenly at room temperature with a constant temperature magnetic stirrer to obtain Composite spinning solution, the diameter of the silica nano-microspheres is 900nm; pour the composite spinning solution into several injection syringes, and then put the several injection syringes into the multi-nozzle electrospinning machine in sequence , adjust the spinning voltage to be 20kV, the spinning distance to be 14cm, the spinning liquid flow rate to be 1.5mL/h, the needle cylinder to traverse distance to 17cm, and the traverse speed to be 30cm/min, start the multi-nozzle electrospinning machine; The surface of the aluminum foil collects electrospun polysulfone fibers with silica nanospheres embedded on the surface; after spinning, a layer of electrospun fiber membrane is formed on the surface of the aluminum foil, which is placed at room temperature for 24 hours, and then the electrospun fiber membrane is removed from the The surface of the aluminum foil was peeled off, and then heat-treated at 190°C for 120 minutes to obtain a ball-and-thread composite fiber air filter material with a stable structure and performance and a thickness of 100.0 μm. Figure 1 shows the ball-and-thread composite fiber in Example 1 Scanning electron microscope image of air filter material.

The ball-wire composite fiber air filter material with a thickness of 100.0 μm has a porosity of 85.7%, an average pore diameter of 5.58 μm, a filtration efficiency of 99.84% for aerosols with a median diameter of 75 nm, and a pressure drop of 330 Pa.

Example 2: 5g of polysulfone particles were weighed with an electronic balance and dissolved in 20g of a mixed solution of dimethylformamide and acetone with a mass ratio of 9:1, and stirred at room temperature with a constant temperature magnetic stirrer to accelerate dissolution, and the preparation Obtain a polysulfone spinning solution with a mass percentage of 20%; weigh 1g of silicon dioxide nano-microspheres with an electronic balance, add them to the above-mentioned 25g polysulfone spinning solution, and stir evenly at room temperature with a constant temperature magnetic stirrer to obtain a composite Spinning solution, the diameter of the silica nano-microspheres is 300nm; pour the composite spinning solution into several injection syringes, and then put the several injection syringes into a multi-nozzle electrospinning machine in sequence, Adjust the spinning voltage to 21kV, the spinning distance to 15cm, the spinning liquid flow rate to 1.0mL/h, the needle cylinder traverse distance to 18cm, and the traverse speed to 28cm/min, start the multi-nozzle electrospinning machine; The surface collects electrospun polysulfone fibers with silica nanospheres embedded on the surface; after spinning, a layer of electrospun fiber membrane is formed on the surface of the aluminum foil, which is placed at room temperature for 36 hours, and then the electrospun fiber membrane is removed from the aluminum foil. The surface was peeled off, and then heat-treated at 190°C for 180 minutes to obtain a ball-and-string composite fiber air filter material with a stable structure and performance and a thickness of 96.1 μm. Scanning electron microscope image of filter material.

The ball-and-wire combined composite fiber air filter material with a thickness of 96.1 μm has a porosity of 86.1%, an average pore size of 6.01 μm, a filtration efficiency of 99.97% for aerosols with a median diameter of 75 nm, and a pressure drop of 302 Pa.

Example 3: Weigh 3.75g of polysulfone particles with an electronic balance and dissolve them in 21.25g of a mixed solution of dimethylformamide and acetone with a mass ratio of 9:1, and stir at room temperature with a constant temperature magnetic stirrer to accelerate dissolution , to prepare a polysulfone spinning solution with a mass percentage of 15%; weigh 1.0 g of silicon dioxide nano-microspheres with an electronic balance, add it to the above 25 g polysulfone spinning solution, and stir it evenly at room temperature with a constant temperature magnetic stirrer , to obtain a composite spinning solution, the diameter of the silica nano-microspheres is 600nm; the composite spinning solution is poured into several injection syringes, and then the several injection syringes are put into the multi-nozzle electrospinning Silk machine, adjust the spinning voltage to be 20kV, the spinning distance to be 18cm, the spinning liquid flow rate to be 1.0mL/h, the needle cylinder to move laterally to 18cm, and to move at a speed of 30cm/min, and start the multi-nozzle electrospinning machine; The surface of the aluminum foil of the drum collects the electrospun polysulfone fibers embedded with silica nano-microspheres; after spinning, a layer of electrospun fiber film is formed on the surface of the aluminum foil, which is placed at room temperature for 24 hours, and then the electrospun fibers are The film was peeled off from the surface of the aluminum foil, and then heat-treated at 190°C for 120 minutes to obtain a ball-and-wire composite air filter material with a stable structure and performance and a thickness of 95.0 μm. Figure 3 shows the ball-and-wire composite air filter material of Example 3 Scanning electron microscope image of composite fiber air filter material.

The ball-wire composite fiber air filter material with a thickness of 95.0 μm has a porosity of 86.3%, an average pore diameter of 5.91 μm, a filtration efficiency of 99.71% for aerosols with a median diameter of 75 nm, and a pressure drop of 292 Pa.

Example 4: Weigh 6.25g of polysulfone particles with an electronic balance and dissolve in 18.75g of a mixed solution of dimethylformamide and acetone with a mass ratio of 9:1, and stir at room temperature with a constant temperature magnetic stirrer to accelerate dissolution , to prepare a polysulfone spinning solution with a mass percentage of 25%; weigh 1.0 g of silicon dioxide nano-microspheres with an electronic balance, add them to the above 25 g of polysulfone spinning solution, and stir evenly at room temperature with a constant temperature magnetic stirrer , to obtain a composite spinning solution, the diameter of the silicon dioxide nano-microspheres is 300nm; the composite spinning solution is poured into several injection syringes, and then the several injection syringes are put into the multi-nozzle electrospinning Silk machine, adjust the spinning voltage to be 20kV, the spinning distance to be 15cm, the spinning liquid flow rate to be 2.5mL/h, the needle cylinder to move laterally to 16cm, and to move at a speed of 30cm/min, and start the multi-nozzle electrospinning machine; The surface of the aluminum foil of the drum collects the electrospun polysulfone fibers embedded with silica nano-microspheres; after spinning, a layer of electrospun fiber film is formed on the surface of the aluminum foil, which is placed at room temperature for 24 hours, and then the electrospun fibers are The film was peeled off from the surface of the aluminum foil, and then heat-treated at 190°C for 180 minutes to obtain a ball-and-wire composite air filter material with a stable structure and performance and a thickness of 102.0 μm. Figure 4 shows the ball-and-wire composite air filter material of Example 4 Scanning electron microscope image of composite fiber air filter material.

The ball-and-wire composite fiber air filter material with a thickness of 102.0 μm has a porosity of 83.6%, an average pore diameter of 4.13 μm, a filtration efficiency of 99.92% for aerosols with a median diameter of 75 nm, and a pressure drop of 341 Pa.

Figures 1 to 4 are scanning electron micrographs of the four ball-and-wire combined composite fiber air filter materials of Examples 1 to 4, respectively. From Figures 1 to 4, it can be seen that a certain amount of silica nanometers are embedded on the surface of the fibers. Microspheres, and the distribution is relatively uniform. The existence of these nano-microspheres increases the surface area of the fiber, which further improves the adsorption capacity of the fiber filter material to dust in the air. Fibrous air filter material has increased filtration efficiency and reduced pressure drop (see Table 1).

Table 1 Filtration performance comparison between ball and wire combined fiber membrane and single polysulfone fiber membrane

sample Sample thickness/μm Filtration efficiency/% Pressure drop/Pa Electrospun polysulfone fiber membrane 99.0 97.23 498 Example 1 (electrospun polysulfone fibers/900nm microspheres) 100.0 99.84 330 Example 2 (electrospun polysulfone fibers/300nm microspheres) 96.1 99.97 302 Example 3 (electrospun polysulfone fibers/600nm microspheres) 95.0 99.71 292 Example 4 (electrospun polysulfone fibers/300nm microspheres) 102.0 99.92 341

Of course, the above-mentioned embodiments are only to illustrate the technical conception and characteristics of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and not to limit the protection scope of the present invention. All modifications made according to the spirit of the main technical solutions of the present invention shall fall within the protection scope of the present invention.

Claims (6)

1. the combined composite fibre air filting material of ball line, is characterized in that, comprises staggered Static Spinning polysulfone fibre, and the silicon dioxide nanosphere that is embedded in described Static Spinning polysulfone fibre surface.

2. the combined composite fibre air filting material of ball line according to claim 1, is characterized in that, the diameter of described Static Spinning polysulfone fibre is 500 ~ 2200nm, and the diameter of described silicon dioxide nanosphere is 300 ~ 900nm.

3. the combined composite fibre air filting material of ball line according to claim 1, it is characterized in that, the porosity of the combined composite fibre air filting material of this ball line is 80 ~ 87%, average pore size is 0.5 μ m ~ 6.5 μ m, to the aerocolloidal filter efficiency of quantity median diameter 75nmNaCl, be 99 ~ 99.99%, pressure is reduced to 150 ~ 500Pa.

4. a preparation method for the combined composite fibre air filting material of ball line as claimed in claim 1, is characterized in that, comprises the following steps:

1) the polysulfones spinning solution that preparation mass fraction is 15% ~ 25%, in this polysulfones spinning solution, add silicon dioxide nanosphere again, the quality of this silicon dioxide nanosphere is 0.5% ~ 6% of this polysulfones spinning solution quality, then, after at room temperature stirring by constant temperature blender with magnetic force, obtain composite spinning liquid;

2) described composite spinning liquid is poured in several injection needle tubes, again these several injection needle tubes are put into multiple spray head static spinning machine successively, with copper bar, each shower nozzle is communicated with, again the positive pole of high-voltage DC power supply is connected with copper bar, negative pole receives cylinder with metal and is connected also ground connection, start this multiple spray head static spinning machine, at the aluminium foil surface that receives cylinder, collect the Static Spinning polysulfone fibre that surface inserting has silicon dioxide nanosphere;

3) after spinning, surface at aluminium foil forms one deck electrostatic spinning fiber film, it is at room temperature placed and is fully volatilized to solvent for 24 ~ 72 hours, again electrostatic spinning fiber film is taken off from aluminium foil surface, then heat treatment 60 ~ 180 minutes at 190 ℃, obtains the combined composite fibre air filting material of ball line of structure and stable performance.

5. the preparation method of the combined composite fibre air filting material of ball line according to claim 4, it is characterized in that, the solvent of described polysulfones spinning solution is the mixed solution of dimethyl formamide and acetone, and the mass ratio of described dimethyl formamide and described acetone is 9:1.

6. the preparation method of the combined composite fibre air filting material of ball line according to claim 4, it is characterized in that, spinning voltage during described multiple spray head static spinning machine work is 15 ~ 30kV, spinning distance is 10 ~ 20cm, spinning solution flow 1.0 ~ 2.5mL/h, the traversing distance 10 ~ 25cm of syringe, syringe transverse moving speed 10 ~ 30cm/min.

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