Multifunctional protective film as well as preparation method and application thereof

Abstract

The invention provides a multifunctional protective film as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) preparation of an electrostatic spraying stock solution: dispersing a flame retardant and super-hydrophobic nanoparticles into a first solvent, carrying out ultrasonic treatment for 30-60 minutes, then adding a macromolecular substance, and stirring at 60-80 DEG C for 30-120 minutes to obtain the electrostatic spraying stock solution; (2) preparation of an electrostatic spinning stock solution: adding polymer particles into a second solvent, and stirring at 40-80 DEG C for 1-5 hours to obtain the electrostatic spinning stock solution; and (3) preparing the multifunctional protective film, namely simultaneously carrying out the electric spraying operation of the electrostatic spraying stock solution and the electric spinning operation of the electrostatic spinning stock solution to obtain the multifunctional protective film. The multifunctional protective film has good water repellency and icing resistance in extremely cold and extremely hot environments, and also has flame retardance.

Description

Technical Field

[0001] The invention belongs to the technical field of nanofibers, and in particular relates to a multifunctional electrostatic spinning protective film for extreme environments and a preparation method thereof. Background Art

[0002] The protective performance of traditional electrospun membranes is mainly reflected in the waterproof and breathable performance, so it is also called waterproof and breathable electrospun membrane. This type of waterproof and breathable membrane is mainly used in fabric fields such as the inner layer of assault jackets, so it needs to face extreme climates such as extreme cold, strong winds, and dust. With the continuous expansion of the application area, the good waterproof and water repellent properties under ordinary conditions can no longer meet the needs of consumers. If the electrospun protective membrane can be given other protective properties on the basis of excellent waterproof performance, such as anti-icing, anti-ice water / hot water, dustproof, etc., then the use scenarios of electrospun membranes will be comprehensively expanded. Therefore, it is very practical to develop a multifunctional electrospun protective membrane for extreme environments. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a multifunctional protective film and a preparation method and application thereof, wherein the multifunctional protective film has good water repellency and anti-icing properties in extremely cold and hot environments, and is flame retardant.

[0004] In order to achieve the above-mentioned purpose, the present invention provides a method for preparing a multifunctional protective film, which comprises the following steps: (1) preparation of an electrostatic spraying stock solution: dispersing a flame retardant and super-hydrophobic nanoparticles into a first solvent, ultrasonicating for 30-60 minutes, and then adding a polymer substance, stirring at 60°C-80°C for 30-120 minutes to obtain an electrostatic spraying stock solution; (2) preparation of an electrostatic spinning stock solution: adding polymer particles into a second solvent, stirring at 40°C-80°C for 1-5 hours to obtain an electrostatic spinning stock solution; (3) preparation of a multifunctional protective film: simultaneously performing electrospraying operation of the electrostatic spraying stock solution and electrospinning operation of the electrostatic spinning stock solution to obtain the multifunctional protective film; the polymer substance comprises polyvinylidene fluoride (PVDF) and polydimethylsiloxane (PDMS).

[0005] According to a specific embodiment of the present invention, preferably, in step (1), the mass ratio of the flame retardant to the first solvent is 3-10:100.

[0006] According to a specific embodiment of the present invention, preferably, the flame retardant includes a combination of two or more of magnesium oxide, magnesium hydroxide and zinc oxide.

[0007] According to a specific embodiment of the present invention, preferably, in step (1), the mass ratio of the super-hydrophobic nanoparticles to the first solvent is 1-3:100.

[0008] According to a specific embodiment of the present invention, preferably, the superhydrophobic nanoparticles include carbon black.

[0009] According to a specific embodiment of the present invention, preferably, in step (1), the mass ratio of the polymer substance to the first solvent is 3-6:100.

[0010] According to a specific embodiment of the present invention, preferably, the polymer substance comprises a mixture of polyvinylidene fluoride and polydimethylsiloxane in a mass ratio of 1:1.

[0011] According to a specific embodiment of the present invention, preferably, in step (2), the mass ratio of the polymer particles to the second solvent is 3-25:100.

[0012] The electrospinning stock solution can be any spinning solution that can be electrospun into a nanofiber membrane. According to a specific embodiment of the present invention, preferably, the electrospinning stock solution is selected from a combination of polyurethane and dimethylformamide (DMF), a combination of polyvinylidene fluoride (PVDF) and dimethylformamide (DMF), a combination of polyvinyl alcohol and water, a combination of nylon and formic acid, a combination of gelatin and water, a combination of zein and ethanol, a combination of polyvinyl pyrrolidone (PVP) and water, a combination of polylactic acid (PLA) and dichloromethane, a combination of poly(ethylene oxide) (PEO) and water, and a combination of polyethylene (PS) and tetrahydrofuran (THF).

[0013] According to a specific embodiment of the present invention, preferably, the first solvent comprises a mixture of dimethylformamide and tetrahydrofuran in a mass ratio of 1:1.

[0014] According to a specific embodiment of the present invention, preferably, in step (3), the electrostatic spraying solution and the electrostatic spinning solution are respectively injected into two independent syringes, and the multifunctional protective film is prepared by a double-needle electrospinning device, and a high voltage of 15-26 kV is applied to the two needles at the same time, and the receiving distance is controlled between 8-20 cm.

[0015] According to a specific embodiment of the present invention, preferably, the injection speed of the electrostatic spraying solution is 0.3-0.9 ml / h, and the injection speed of the electrostatic spinning solution is 0.1-0.3 ml / h.

[0016] According to a specific embodiment of the present invention, preferably, the ratio of the injection speed of the electrostatic spraying solution to the injection speed of the electrostatic spinning solution is 2-3:1.

[0017] According to a specific embodiment of the present invention, the above preparation method comprises the following specific steps:

[0018] (1) Preparation of electrostatic spray stock solution: a certain amount of flame retardant powder and super-hydrophobic nanoparticles are dispersed in a first solvent, ultrasonicated for 30-60 minutes, and then a certain amount of polymer is added, placed in a water bath at 60° C.-80° C., rapidly stirred for 30-120 minutes, and then taken out to obtain a black, uniform, low-viscosity electrostatic spray stock solution, which is cooled to room temperature for later use;

[0019] (2) Preparation of electrospinning stock solution: adding a certain mass of polymer particles into the second solvent, stirring at 40°C-80°C for 1-5 hours, and cooling to obtain a viscous and uniform electrospinning stock solution;

[0020] (3) Preparation of electrospun membrane containing micro-nanoparticles: Aluminum foil or silicone oil paper is used as a receiving substrate, which is wrapped around the surface of a drum. The electrostatic spraying solution and the electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. A high voltage of 15-26 kV is applied to the two needles through a double-needle electrospinning device. The receiving distance is controlled between 8-20 cm. After spinning for 2-20 hours, the receiving substrate and the obtained electrospun membrane are removed together, placed in an oven at 40°C-60°C for 24-48 hours, and then the electrospun membrane is removed to obtain the multifunctional protective membrane.

[0021] The present invention also provides a multifunctional protective film prepared by the above preparation method.

[0022] The present invention also provides the use of the multifunctional protective film in waterproof products, such as outdoor jackets, waterproof raincoats, firefighter protective clothing, etc.

[0023] The multifunctional electrospinning protective film of the present invention not only has excellent water repellency and moisture permeability, but also can maintain good superhydrophobicity in extreme weather conditions, whether it is extremely cold or high temperature, and also has anti-icing, self-cleaning and certain flame retardancy. The preparation method of this multifunctional electrospinning protective film has strong universality, controllability, and feasibility, and is suitable for all electrospinning polymers. The present invention has the following beneficial effects:

[0024] 1. The synergistic effect of electrostatic spraying and electrostatic spinning can construct a super-hydrophobic nanofiber membrane with uniform structure inside and outside;

[0025] 2. One-step preparation method, low cost, non-toxic and harmless;

[0026] 3. It has a wider range of uses and application scenarios;

[0027] 4. It has water repellency, cold / hot water repellency, self-cleaning, anti-icing and flame retardant properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a photo of a 60°C water stream hitting the multifunctional electrospun protective film on the arm and then bouncing off;

[0029] Figure 2 This is a scanning electron microscope image of the multifunctional electrospun protective film;

[0030] Figure 3 The heat release rate and total heat release results of the combustion experiment of ordinary electrospun PU film and multifunctional electrospun protective film;

[0031] Figure 4 It is the surface contact angle photos of various liquids;

[0032] Figure 5 The freezing time of water droplets on the surface of electrospun PU film and multifunctional electrospun protective film;

[0033] Figure 6 This is a photo of the rapid shedding process of ice droplets on the surface of the multifunctional electrospun protective film;

[0034] Figure 7 The graphs are the changes of contact angle of the super hydrophobic film after washing and stirring in ice water and hot water bath at 0℃ and 90℃ for 1h;

[0035] Figure 8 This is a scanning electron microscope image of a PVA-based superhydrophobic electrospun protective film;

[0036] Fig. 9 Statistical curves of water contact angles of three films after 30 friction cycles. DETAILED DESCRIPTION

[0037] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0038] Example 1

[0039] This embodiment provides a multifunctional protective film, and the preparation method thereof is as follows:

[0040] (1) Preparation of electrostatic spray stock solution: 0.5g magnesium hydroxide powder and 0.2g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5g DMF and 5g THF. After ultrasonication for 30min, 0.25g PVDF and 0.25g PDMS were added, placed in a 60°C water bath, stirred rapidly for 120min, and then taken out to obtain a black, uniform, low-viscosity electrostatic spray stock solution, which was cooled to room temperature for later use;

[0041] (2) Preparation of electrospinning stock solution: 0.8 g of polyurethane particles were added to 10 g of DMF solvent and stirred at 80 °C for 2 h. After cooling, a viscous and uniform electrospinning stock solution was obtained;

[0042] (3) Preparation of electrospinning membrane containing micro-nanoparticles: Aluminum foil is used as the receiving substrate and is wrapped around the surface of the drum. The electrostatic spraying solution and electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. The electrospray rate is set to 0.9 ml / h, and the electrospinning rate is set to 0.3 ml / h. Through a double-needle electrospinning device, a high voltage of 18 kV is applied to the two needles at the same time, and the receiving distance is controlled at 10 cm. After spinning for 5 hours, the receiving substrate and the obtained electrospinning membrane are removed together, placed in a 40°C oven for 24 hours, and then the obtained multifunctional electrospinning protective film is removed. The optical photograph of the protective film on the hand is as follows. Figure 1 As shown in Figure 1, the 60℃ hot water flow is completely rejected. The scanning electron microscope image is shown in Figure 1. Figure 2 shown.

[0043] The flame retardant properties of the material were evaluated by microscale combustion calorimetry (MCC) to monitor the real combustion behavior of the material under fire scenarios, and the measured temperature range was 70℃-750℃. Compared with the pure polyurethane electrospun membrane, the heat release rate during combustion was significantly reduced, showing good flame retardancy, such as Figure 3 As shown; the preparation method of the pure polyurethane electrospinning membrane is as follows:

[0044] 0.8g polyurethane particles were added to 10g DMF solvent and stirred at 80℃ for 2h. After cooling, a viscous and uniform electrospinning stock solution was obtained. The spinning solution was injected into the syringe, and 18kV high voltage was applied to the needle. The receiving distance was 10cm. After spinning for 5h, the receiving substrate and the obtained electrospinning membrane were removed together, and the obtained PU electrospinning membrane was removed after being placed in a 40℃ oven for 24h.

[0045] The two membrane samples were placed in a -5℃ refrigerator. About 100μl of water droplets were added to the surface of the membrane, and the entire freezing process was recorded with a camera. Compared with the pure PU electrospun membrane, the freezing time of water droplets on the surface of the obtained multifunctional protective membrane was significantly prolonged under -5℃ environment, showing good anti-icing properties. Figure 5 ; and in the sun, ice droplets can detach from the membrane surface within 2 seconds, which has an excellent de-icing effect. Figure 6 .

[0046] Example 2

[0047] This embodiment provides a multifunctional protective film, and the preparation method thereof is as follows:

[0048] (1) Preparation of electrostatic spray stock solution: 0.8g zinc oxide powder and 0.15g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5g DMF and 5g THF. After ultrasonication for 60min, 0.25g PVDF and 0.25g PDMS were added, placed in a 60°C water bath, stirred rapidly for 60min, and then taken out to obtain a black, uniform, low-viscosity electrostatic spray stock solution, which was cooled to room temperature for later use;

[0049] (2) Preparation of electrospinning solution: 2.4 g PVDF particles were added to 10 g DMF solvent and stirred at 60 °C for 3 h. After cooling, a viscous and uniform electrospinning solution was obtained;

[0050] (3) Preparation of electrospinning membrane containing micro-nanoparticles: Aluminum foil is used as the receiving substrate and is wrapped around the surface of the drum. The electrostatic spraying solution and electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. Through a double-needle electrospinning device, a high voltage of 22kV is applied to the two needles at the same time, and the receiving distance is controlled at 10cm. The electrospray rate is set to 0.9ml / h, and the electrospinning rate is set to 0.3ml / h. After spinning for 3 hours, the receiving substrate and the obtained electrospinning membrane are removed together, placed in a 60°C oven for 24 hours, and then the obtained multifunctional electrospinning protective membrane is removed.

[0051] At room temperature and pressure, the multifunctional electrospun protective film is placed flat on a glass sheet. A 5μl droplet is slowly and gently added to its surface using a micro syringe. A macro camera is used to record the droplet photo, and finally the contact angle measurement software is used to test the specific value of its contact angle. The contact angles of various liquids on its surface are as follows: Figure 4 As shown, it proves that it has excellent hydrophobicity.

[0052] Example 3

[0053] This embodiment provides a multifunctional protective film, and the preparation method thereof is as follows:

[0054] (1) Preparation of electrostatic spray stock solution: 1g magnesium oxide powder and 0.3g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5g DMF and 5g THF. After ultrasonication for 40min, 0.25g PVDF and 0.25g PDMS were added, placed in a 70°C water bath, stirred rapidly for 100min, and then taken out to obtain a black, uniform, low-viscosity electrostatic spray stock solution, which was cooled to room temperature for later use;

[0055] (2) Preparation of electrospinning stock solution: 1.4 g of nylon particles were added to 10 g of formic acid solvent and stirred at 70 °C for 1 h. After cooling, a viscous and uniform electrospinning stock solution was obtained;

[0056] (3) Preparation of electrospinning membrane containing micro-nanoparticles: Aluminum foil is used as the receiving substrate and is wrapped around the surface of the drum. The electrostatic spraying solution and electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. Through a double-needle electrospinning device, a high voltage of 26kV is applied to the two needles at the same time, and the receiving distance is controlled at 8cm. The electrospray rate is set to 0.9ml / h, and the electrospinning rate is set to 0.3ml / h. After spinning for 12 hours, the receiving substrate and the obtained electrospinning membrane are removed together, placed in a 60°C oven for 30 hours, and then the obtained multifunctional electrospinning protective membrane is removed. It is placed in an ice water bath and a hot water bath at 0°C and 90°C, respectively, and washed and stirred for 1 hour, and the change in the surface water droplet contact angle with the washing time is measured, such as Figure 7 As shown, Figure 7 In the figure, the triangle represents hot water and the square represents ice water. The results show that ice water and hot water do not destroy its hydrophobicity.

[0057] Example 4

[0058] This embodiment provides a multifunctional protective film, and the preparation method thereof is as follows:

[0059] (1) Preparation of electrostatic spray stock solution: 1g magnesium hydroxide powder and 0.3g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5g DMF and 5g THF. After ultrasonication for 50min, 0.25g PVDF and 0.25g PDMS were added, placed in a 60°C water bath, stirred rapidly for 120min, and then taken out to obtain a black, uniform, low-viscosity electrostatic spray stock solution, which was cooled to room temperature for later use;

[0060] (2) Preparation of electrospinning solution: 1.5 g of PVA particles were added to 10 g of water and stirred at 70 °C for 1 h. After cooling, a viscous and uniform electrospinning solution was obtained;

[0061] (3) Preparation of electrospinning membrane containing micro-nanoparticles: Aluminum foil is used as the receiving substrate and is wrapped around the surface of the drum. The electrostatic spraying solution and electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. The electrospray rate is set to 0.9 ml / h, and the electrospinning rate is set to 0.3 ml / h. Through a double-needle electrospinning device, a high voltage of 16 kV is applied to the two needles at the same time, and the receiving distance is controlled at 15 cm. After spinning for 20 hours, the receiving substrate and the obtained electrospinning membrane are removed together, placed in a 40°C oven for 20 hours, and then the obtained multifunctional electrospinning protective membrane is removed. The scanning electron microscope image is as follows Figure 8 As shown in Figure 2, water droplets are spherical on the surface of the multifunctional electrospun protective film, showing super hydrophobicity.

[0062] Comparative Example 1

[0063] This comparative example provides a non-superhydrophobic electrospinning membrane as a control, and its preparation method is as follows:

[0064] (1) Preparation of electrostatic spray stock solution: 0.5 g magnesium hydroxide powder and 0.2 g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5 g DMF and 5 g THF. After ultrasonication for 30 min, 0.25 g PDMS was added, placed in a 60°C water bath, rapidly stirred for 120 min, and then taken out to obtain a black low-viscosity electrostatic spray stock solution, which was cooled to room temperature for later use;

[0065] (2) Preparation of electrospinning stock solution: 0.8 g of polyurethane particles were added to 10 g of DMF solvent and stirred at 80 °C for 2 h. After cooling, a viscous and uniform electrospinning stock solution was obtained;

[0066] (3) Preparation of electrospun membrane containing micro-nanoparticles: Aluminum foil is used as the receiving substrate and is wrapped around the surface of the drum. The electrostatic spraying solution and electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. The electrospraying rate is set to 0.9 ml / h, and the electrospinning rate is set to 0.3 ml / h. Through a double-needle electrospinning device, a high voltage of 18 kV is applied to the two needles at the same time, and the receiving distance is controlled at 10 cm. After spinning for 5 hours, the receiving substrate and the obtained electrospinning membrane are removed together, and the obtained electrospinning protective film is removed after being placed in a 40°C oven for 24 hours. A 5 μl droplet is slowly and gently dripped onto its surface, and its water contact angle is measured to be 142°, which does not meet the superhydrophobic standard. This comparative example reflects the necessity of PVDF.

[0067] Comparative Example 2

[0068] This comparative example provides an unfeasible electrospinning membrane preparation method as a control, and the preparation method is as follows:

[0069] (1) Preparation of electrostatic spray stock solution: 1g magnesium hydroxide powder and 0.2g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5g DMF and 5g THF. After ultrasonication for 30min, 0.25g PDMS was added, placed in a 60°C water bath, rapidly stirred for 120min, and then taken out to obtain a black low-viscosity electrostatic spray stock solution, which was cooled to room temperature for use;

[0070] (2) Preparation of electrospinning stock solution: 0.8 g of polyurethane particles were added to 10 g of DMF solvent and stirred at 80 °C for 2 h. After cooling, a viscous and uniform electrospinning stock solution was obtained;

[0071] (3) Preparation of electrospinning membrane containing micro-nanoparticles: Aluminum foil is used as the receiving substrate and is wrapped around the drum surface. The electrostatic spraying solution and electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. The electrospraying rate is set to 0.9 ml / h, and the electrospinning rate is set to 0.3 ml / h. Through a double-needle electrospinning device, a high voltage of 18 kV is applied to the two needles at the same time, and the receiving distance is controlled at 10 cm. When spinning starts, the electrospray liquid is blocked and stable spraying cannot be achieved. This shows that the content of magnesium hydroxide powder must be within a certain range to be feasible.

[0072] Comparative Example 3

[0073] This comparative example provides an unfeasible method for preparing a multifunctional protective film, and the preparation method is as follows:

[0074] (1) Preparation of electrostatic spray stock solution: 0.5g magnesium hydroxide powder and 0.2g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5g DMF and 5g THF. After ultrasonication for 30min, 0.25g PVDF and 0.25g PDMS were added, placed in a 60°C water bath, stirred rapidly for 120min, and then taken out to obtain a black, uniform, low-viscosity electrostatic spray stock solution, which was cooled to room temperature for later use;

[0075] (2) Preparation of electrospinning stock solution: 0.8 g of polyurethane particles were added to 10 g of DMF solvent and stirred at 80 °C for 2 h. After cooling, a viscous and uniform electrospinning stock solution was obtained;

[0076] (3) Preparation of electrospun membrane containing micro-nanoparticles: Aluminum foil is used as the receiving substrate and is wrapped around the drum surface. The electrostatic spraying solution and electrospinning solution obtained in step (1) and step (2) are respectively injected into two independent syringes. The electrospraying rate is set to 1.2 ml / h, and the electrospinning rate is set to 0.2 ml / h. Through a double-needle electrospinning device, a high voltage of 18 kV is applied to the two needles at the same time, and the receiving distance is controlled at 10 cm. After spinning for 5 hours, it was found that only incomplete and broken electrospun membranes could be obtained on the substrate. This shows that the electrospraying rate and electrospinning rate need to be controlled within a certain range to be feasible.

[0077] Comparative Example 4

[0078] This comparative example provides two methods for preparing multifunctional protective films with weak mechanical strength, and the preparation methods are as follows:

[0079] (1) Add 0.8g of polyurethane particles to 10g of DMF solvent and stir at 80℃ for 2h. After cooling, a viscous and uniform electrospinning stock solution is obtained. Then add 1g of magnesium hydroxide powder, 0.2g of superhydrophobic carbon black nanoparticles, 0.25g of PVDF and 0.25g of PDMS to the above electrospinning stock solution and stir for 24h to obtain the final mixed spinning solution. Inject it into a syringe and apply 18kV high voltage to the needle with a receiving distance of 10cm. After spinning for 5h, a mixed electrospinning membrane is obtained on the receiving substrate, named M-①.

[0080] (2) Preparation of electrostatic spray stock solution: 1g magnesium hydroxide powder and 0.2g superhydrophobic carbon black nanoparticles were dispersed in a mixed organic solvent of 5g DMF and 5g THF. After ultrasonication for 30min, 0.25g PVDF and 0.25g PDMS were added, placed in a 60°C water bath, stirred rapidly for 120min, and then taken out to obtain a black low-viscosity electrostatic spray stock solution, which was cooled to room temperature for use;

[0081] (3) Preparation of electrospinning stock solution: 0.8 g of polyurethane particles were added to 10 g of DMF solvent and stirred at 80 °C for 2 h. After cooling, a viscous and uniform electrospinning stock solution was obtained;

[0082] (4) The electrospinning stock solution obtained in step (3) was injected into a syringe, and a high voltage of 18 kV was applied to the needle, and the receiving distance was 10 cm. After spinning for 5 hours, a PU electrospinning membrane was obtained on the receiving substrate. With this membrane as the receiving substrate, the electrostatic spraying stock solution obtained in step (2) was injected into a new syringe, and a high voltage of 18 kV was applied to the needle, and the receiving distance was 10 cm. A layer of super-hydrophobic particles was electrosprayed on the surface of the PU electrospinning membrane to make it a super-hydrophobic membrane, which was named M-②.

[0083] (5) The multifunctional protective film in Example 1 is named M-③. A friction cycle test was conducted on M-①, M-② and M-③. The three films (~2×2 cm) were attached to a clean and flat glass sheet with double-sided tape. Then, the film was placed on a rough cotton cloth and pressed against the glass sheet with a load of 50 g. The sample moved 10 cm along the ruler as a cycle. A total of 30 wear tests were conducted. Finally, the water contact angle of the film surface after the friction cycle was measured. The results are shown in Table 1. Fig. 9 The results show that after 30 friction cycles, M-③ still retains a certain degree of hydrophobicity, while the other two contact angles are significantly reduced. This shows that the multifunctional protective film of the present invention has better mechanical stability.

[0084] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a multifunctional protective film, comprising the following steps: (1) Preparation of electrostatic spray stock solution: disperse the flame retardant and super-hydrophobic nanoparticles in the first solvent, ultrasonicate for 30-60 minutes, then add the polymer substance, stir at 60° C.-80° C. for 30-120 minutes to obtain the electrostatic spray stock solution; (2) Preparation of electrospinning stock solution: adding polymer particles to the second solvent, stirring at 40° C.-80° C. for 1-5 hours, to obtain electrospinning stock solution; (3) Preparation of a multifunctional protective film: performing electrospraying of the electrostatic spraying solution and electrospinning of the electrostatic spinning solution simultaneously to obtain the multifunctional protective film; The polymer substance includes polyvinylidene fluoride and polydimethylsiloxane.

2. The preparation method according to claim 1, wherein In step (1), the mass ratio of the flame retardant to the first solvent is 3-10:100; Preferably, the flame retardant includes a combination of two or more of magnesium oxide, magnesium hydroxide and zinc oxide.

3. The preparation method according to claim 1, wherein In step (1), the mass ratio of the super-hydrophobic nanoparticles to the first solvent is 1-3:100; Preferably, the superhydrophobic nanoparticles comprise carbon black.

4. The preparation method according to claim 1, wherein In step (1), the mass ratio of the polymer substance to the first solvent is 3-6:100; Preferably, the polymer substance comprises a mixture of polyvinylidene fluoride and polydimethylsiloxane in a mass ratio of 1:

1.

5. The preparation method according to claim 1, wherein In step (2), the mass ratio of the polymer particles to the second solvent is 3-25:

100.

6. The preparation method according to claim 1, wherein The electrospinning stock solution is selected from a combination of polyurethane and dimethylformamide, a combination of polyvinylidene fluoride and dimethylformamide, a combination of polyvinyl alcohol and water, a combination of nylon and formic acid, a combination of gelatin and water, a combination of zein and ethanol, a combination of polyvinyl pyrrolidone and water, a combination of polylactic acid and dichloromethane, a combination of polyhexyl oxide and water, and a combination of polyethylene and tetrahydrofuran.

7. The preparation method according to claim 1, wherein The first solvent includes a mixture of dimethylformamide and tetrahydrofuran in a mass ratio of 1:

1.

8. The preparation method according to claim 1, wherein In step (3), the electrostatic spraying solution and the electrostatic spinning solution are respectively injected into two independent syringes, and the multifunctional protective film is prepared by a double-needle electrospinning device, and a high voltage of 15-26 kV is applied to the two needles at the same time, and the receiving distance is controlled between 8-20 cm; Preferably, the injection speed of the electrostatic spraying solution is 0.3-0.9 ml / h, and the injection speed of the electrostatic spinning solution is 0.1-0.3 ml / h; Preferably, the ratio of the injection speed of the electrostatic spraying solution to the injection speed of the electrostatic spinning solution is 2-3:

1.

9. The multifunctional protective film obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the multifunctional protective film according to claim 9 in waterproof products; Preferably, the waterproof product includes outdoor jackets, waterproof raincoats or firefighter protective clothing.

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