CN111850824A - A kind of preparation method of submicron composite membrane - Google Patents

Abstract

The invention discloses a preparation method of a submicron composite membrane. First, after mixing an appropriate amount of N,N-dimethylformamide and N-methylpyrrolidone, an appropriate amount of polyetherimide solution is added while stirring, and after stirring uniformly After adding an appropriate amount of silica nanoparticles and stirring uniformly, a composite membrane was obtained by an electrospinning machine. The method has simple preparation process, low cost of raw materials, the diameter of the prepared composite membrane is in nanometer scale, and the packing density is controllable; it has high porosity, can effectively filter out micro- and nano-scale impurities, and improves the filtration precision and filtration efficiency; Thermal stability, chemical stability and hydrolytic stability. It has super-hydrophobicity, self-cleaning and oil-water separation characteristics, prolonging service life and reducing maintenance frequency; it has high charge storage capacity, can continuously show electrification, and improve the filtration efficiency of small particles.

Description

A kind of preparation method of submicron composite membrane

technical field

The invention belongs to the field of nanomaterials, and in particular relates to a preparation method of a submicron composite membrane.

Background technique

In the electrical field, insulating oil is widely used, but the problem of filtration and regeneration of insulating oil is still one of the technical problems in the industry. There are a large number of nano-scale particles and acidic colloids dissolved in the used insulating oil. The conventional filtration method cannot filter the fine particles with micro-sized particles because of the large voids and uncontrollable bulk density of the existing filtration membrane. Therefore, the recycled insulation is often recycled. The oil process is complicated and troublesome, resulting in waste of insulating oil. In order to separate insulating oil efficiently and at low cost, fiber membrane technology is undoubtedly a relatively energy-saving and cost-effective method. Therefore, a new type of fiber membrane with good heat resistance, chemical stability and hydrolysis stability was invented. Membranes must also have good charge retention, controllable packing density and high porosity are particularly important.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the disadvantages of large voids and uncontrollable bulk density of the existing fiber membrane, and to provide a preparation method of a submicron composite membrane.

The specific plans are as follows:

The key to a preparation method of a submicron composite membrane is that it comprises the following steps:

S1. Add an appropriate amount of N,N-dimethylformamide and N-methylpyrrolidone into the polyetherimide solution and mix evenly to form a mixed solution A;

S2. Add an appropriate amount of silica nanoparticles to the above-mentioned mixed solution A and stir for more than 2-4h to obtain a mixed solution B;

S3. using an electrospinning machine to imitate the above mixed solution B to obtain a submicron composite membrane;

As a preferred solution, the mass fraction of N,N-dimethylformamide and N-methylpyrrolidone in step S1 is 1%, and the mass fraction of the polyetherimide solution is 20%.

As a preferred solution, the mass fraction of the silica nanoparticles in step S2 is 2%.

As a preferred solution, the spinning voltage of the electrospinning machine described in step S3 is 25kV, the receiving distance is 8-12cm, the solution supply speed is 1mL/h, and the rotating speed of the receiving drum is 45-55rpm.

As a preferred solution, the composite membrane obtained in step S3 also needs to be dried in a vacuum oven for 2-4 hours to remove residual solvent.

As a preferred solution, in the step S1, the N,N-dimethylformamide and N-methylpyrrolidone are first mixed and placed on a magnetic stirrer, and then the polyetherimide solution is added while stirring Stir well.

Beneficial effects: the preparation method of a submicron composite membrane of the present invention has the advantages of simple preparation process and low cost of raw materials, the diameter of the prepared composite membrane is in the nanometer scale, and the packing density can be controlled; , Nano-scale impurities, improve filtration precision and filtration efficiency; have good thermal stability, chemical stability and hydrolysis stability. It has super-hydrophobicity, self-cleaning and oil-water separation characteristics, prolonging service life and reducing maintenance frequency; it has high charge storage capacity, can continuously show electrification, and improve the filtration efficiency of small particles.

Description of drawings

Fig. 1 is the process flow schematic diagram of the present invention;

Fig. 2 is the surface topography of the PEI-SiO ₂ composite film prepared by the present invention observed by field emission electron microscope.

Detailed ways

Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail:

Embodiment: a preparation method of submicron composite membrane, comprising the following steps:

S1. First mix an appropriate amount of N,N-dimethylformamide and N-methylpyrrolidone and place it on a magnetic stirrer, then add the polyetherimide solution while stirring to form a mixed solution A, in which the mixed solution The mass fraction of N,N-dimethylformamide and N-methylpyrrolidone in A is 1%, and the mass fraction of the polyetherimide solution is 20%;

S2. Add an appropriate amount of silica nanoparticles to the above mixed solution A and stir for more than 2-4 hours to obtain a mixed solution B, wherein the mass fraction of the silica nanoparticles in the mixed solution B is 2%. ;

S3. above-mentioned mixed solution B is imitated to obtain submicron composite film by electrospinning machine, the spinning voltage of described electrospinning machine is 25kV, and the receiving distance is 8-12cm, and the solution supply speed is 1mL/h, and the The rotation speed is 45-55 rpm, and then the obtained product is placed in a vacuum oven with a temperature of 22-26° C. for drying for 2-4 hours to remove residual solvent.

As shown in Figure 2, the diameter of the submicron composite membrane prepared by this method is in the nanometer scale and has high porosity, which can effectively filter out micro- and nano-scale impurities, and improve the filtration precision and filtration efficiency; it has good thermal stability, Chemical stability and hydrolytic stability; with super-hydrophobicity, self-cleaning and oil-water separation characteristics, prolonging service life and reducing maintenance frequency; high charge storage capacity, can continue to show stagnation, and improve resistance to small particles filtration efficiency.

Finally, it should be noted that the above description is only a preferred embodiment of the present invention, and those of ordinary skill in the art can make a variety of similar It is indicated that such transformations fall within the protection scope of the present invention.

Claims (6)

1. a preparation method of submicron composite membrane, is characterized in that, comprises the following steps: S1. Add an appropriate amount of N,N-dimethylformamide and N-methylpyrrolidone into the polyetherimide solution and mix evenly to form a mixed solution A; S2. Add an appropriate amount of silica nanoparticles to the above-mentioned mixed solution A and stir for more than 2-4h to obtain a mixed solution B; S3. Use an electrospinning machine to imitate the above mixed solution B to obtain a submicron composite membrane. 2. The preparation method of a submicron composite membrane according to claim 1, wherein the mass fraction of N,N-dimethylformamide and N-methylpyrrolidone described in step S1 is 1%, The mass fraction of the polyetherimide solution is 20%. 3 . The method for preparing a submicron composite membrane according to claim 1 or 2 , wherein the mass fraction of the silica nanoparticles in step S2 is 2%. 4 . 4. the preparation method of a kind of submicron composite membrane according to claim 3 is characterized in that: the spinning voltage of the electrospinning machine described in step S3 is 25kV, the receiving distance is 8-12cm, and the solution supply speed is 1mL/h, the rotating speed of the receiving drum is 45-55rpm. 5 . The method for preparing a submicron composite membrane according to claim 1 , wherein the composite membrane obtained in step S3 also needs to be dried in a vacuum oven for 2-4 hours to remove residual solvent. 6 . 6. the preparation method of a kind of submicron composite membrane according to claim 1, is characterized in that: described N,N-dimethylformamide and N-methylpyrrolidone are mixed first in described step S1 and then placed On a magnetic stirrer, the polyetherimide solution was added while stirring and stirred uniformly.

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