Chemical crosslinking carbon nanotube electromagnetic shielding degradable film and preparation method thereof

Abstract

The invention relates to the technical field of medical films, in particular to a chemically crosslinked carbon nanotube electromagnetic shielding degradable film and a preparation method thereof. The chemically crosslinked carbon nanotube electromagnetic shielding degradable film is prepared from 1-4 parts of carbon nanotubes containing carboxyl and hydroxyl on the surface, 20-28 parts of PVA resin, 2-4 parts of a plasticizer, 160-240 parts of pure water and 1-10 parts of a cross-linking agent, wherein the cross-linking agent is a metal ion cross-linking agent or small organic molecules carrying at least one carboxyl or aldehyde functional group; the carbon nano tube with the surface containing carboxyl and hydroxyl and the hydroxyl on the PVA molecular chain are grafted to the peripheral side of the PVA molecular chain through metal ion competitive coordination reaction or esterification reaction, so that the dispersion uniformity of the carbon nano tube and the connection stability of the carbon nano tube and the PVA molecular chain are improved; the prepared film has good degradability, antistatic property and electromagnetic shielding property, can be used in the field of medical non-woven fabric, and improves the safety of medical staff.

Description

Technical Field

[0001] The present application relates to the technical field of medical films, and in particular to a degradable film for shielding electromagnetic waves using chemically cross-linked carbon nanotubes and a preparation method thereof. Background Art

[0002] With the development of modern high-tech, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) issues caused by electromagnetic waves are becoming increasingly serious. These issues not only interfere with and damage electronic instruments and equipment, affecting their proper function and severely limiting their international competitiveness, but also cause environmental pollution and other problems. In particular, electromagnetic pulse (EMP) weapons, a new concept weapon, have achieved substantial breakthroughs. These weapons can directly strike electronic equipment, power systems, and other systems, causing temporary or permanent damage to information systems. Their diverse delivery methods and destructive power are extremely powerful, and the powerful EMPs can also cause damage to the human body. With the widespread use of large-scale electromagnetic equipment such as magnetic resonance imaging (MRI), X-rays, and positron emission tomography (PET) scanners in hospitals, there is a shortage of relevant EMI protection products in the medical field.

[0003] Polyvinyl alcohol (PVA) films, due to their excellent high and low temperature resistance, corrosion resistance, high tensile strength, and flexibility, are used in a wide range of applications, including various plastic products, food packaging, disposable food containers, nonwovens, and industrial and household textiles. Furthermore, with growing environmental awareness, the inherent biodegradability of PVA films has garnered widespread attention, making them a promising market. However, existing PVA products lack electromagnetic (EMI) shielding properties in medical protection, limiting their application. A biodegradable film containing chemically cross-linked carbon nanotubes and a method for its preparation are urgently needed. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a method for preparing a degradable film of chemically cross-linked carbon nanotubes for electromagnetic shielding.

[0005] The present invention provides a chemically cross-linked carbon nanotube degradable film for electromagnetic shielding, which is achieved through the following technical solutions:

[0006] A chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is made of the following raw materials in parts by weight: 1-4 parts of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 20-28 parts of PVA resin, 2-4 parts of plasticizer, 160-240 parts of pure water, and 1-10 parts of a cross-linking agent; the cross-linking agent is a metal ion cross-linking agent or an organic small molecule carrying at least one carboxyl or aldehyde functional group; the plasticizer is a combination of one or more of glycerol, ethylene glycol, propylene glycol, and butylene glycol.

[0007] Preferably, the organic small molecule carrying at least one carboxyl or aldehyde functional group is any one of malonic acid, 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,5-pentanedioic acid, 1,7-pimelic acid, 1,9-nonanedioic acid, and 1,10-decanedioic acid.

[0008] Preferably, the metal cation generated in the metal ion crosslinking agent is Fe 3+ 、Fe 2+ 、Cu 2+ 、Cu + 、Zn 2+ 、Mn 2+ , Pb 2+ 、Ag + 、Al 3+ 、Au + At least one of .

[0009] Preferably, the metal ion crosslinking agent is at least one of copper sulfate, copper chloride, copper nitrate, manganese sulfate, manganese chloride, manganese nitrate, zinc sulfate, zinc chloride, zinc nitrate, ferric chloride, ferric nitrate, aluminum sulfate, aluminum nitrate, lead chloride, lead nitrate, lead acetate, silver nitrate, and chloroauric acid.

[0010] When the cross-linking agent is a metal ion cross-linking agent, the composite process of PVA-OH and HO-CNTs-COOH through esterification reaction with the metal ion cross-linking agent is as follows:

[0011]

[0012] Inorganic metal salts dissociate into metal ions Me n+ It exists in the form of coordination inside the PVA degradable film, which can improve the antibacterial, anti-mildew, electromagnetic shielding and antistatic effects of the PVA film.

[0013] When the cross-linking agent is a metal ion cross-linking agent, the composite process of PVA-OH and HO-CNTs-COOH through esterification reaction with organic small molecules carrying at least one carboxyl or aldehyde functional group is as follows:

[0014]

[0015] The chemical cross-linking agent is an organic small molecule carrying at least one carboxyl or aldehyde functional group. In the solution, PVA-OH and HO-CNTs-COOH are compounded through esterification reaction with the chemical cross-linking agent, which can improve the electromagnetic shielding and antistatic effects of the PVA film.

[0016] Preferably, the carbon nanotubes containing carboxyl and hydroxyl groups on the surface include carboxyl groups -COOH and hydroxyl groups -OH, and also include at least one of amino groups -NH2, thiol groups -SH, aldehyde groups -CHO, and epoxy groups -CH(O)CH-.

[0017] Preferably, the preparation method of the carbon nanotubes containing carboxyl and hydroxyl groups on the surface is as follows: using a strong acid or a strong oxidant or a Fenton reagent or plasma to treat carbon nanotubes CNTs, at least carboxyl -COOH and hydroxyl -OH functional groups are introduced into the surface of CNTs, and the carbon nanotubes containing carboxyl and hydroxyl groups on the surface are modified.

[0018] Preferably, the carbon nanotubes are single-walled carbon nanotubes and / or multi-walled carbon nanotubes; the carbon nanotubes containing carboxyl and hydroxyl groups on the surface are single-walled carbon nanotubes containing carboxyl and hydroxyl groups on the surface and / or multi-walled carbon nanotubes containing carboxyl and hydroxyl groups on the surface.

[0019] Preferably, the alcoholysis degree of the PVA is ≥79%, the polymerization degree is 300-2400, and the PVA includes at least one of PVA-2499, PVA-1788, PVA-1799, and PVA-2388.

[0020] In the present invention, carbon nanotubes are carboxylated and modified. The resulting carboxyl-modified carbon nanotubes react with the hydroxyl groups on the PVA resin through a competitive coordination reaction with metal ions, thereby grafting the carbon nanotubes onto the sides of the PVA molecular chains. This improves the dispersion uniformity of the carbon nanotubes and the connection stability with the PVA molecular chains, and imparts good biodegradability, antistatic properties, and antibacterial and mildew-proof properties to the prepared film. The metal ions and the carbon nanotubes produce a synergistic effect, giving the prepared film better electromagnetic shielding properties. The EMI performance SE in the X-band (8.2-12.4 GHz) is 17-45 dB, and it can be used in the field of medical nonwovens to improve the safety of medical staff.

[0021] Further preferably, the metal cation generated in the metal ion crosslinking agent is Fe 3+ 、Cu 2+ 、Al 3+ 、Ag + At least one of the metal ion cross-linking agent is copper sulfate, copper chloride, copper nitrate, ferric chloride, ferric nitrate, aluminum sulfate, aluminum nitrate, and silver nitrate.

[0022] In the present invention, Fe is selected 3+ 、Cu 2+ 、Al 3+ 、Ag + At least one of them is compounded with carbon nanotubes containing carboxyl and hydroxyl groups on the surface, and the prepared film has a relatively better electromagnetic shielding effect. That is, under the same electromagnetic shielding effect, the amount of carbon nanotubes containing carboxyl and hydroxyl groups on the surface and metal ion crosslinking agent can be reduced, thereby optimizing the cost of the degradable film of chemically crosslinked carbon nanotubes for electromagnetic shielding.

[0023] The present invention provides a method for preparing a degradable film of chemically cross-linked carbon nanotubes for electromagnetic shielding, which is achieved through the following technical solutions:

[0024] A method for preparing a chemically cross-linked carbon nanotube degradable film for electromagnetic shielding comprises the following steps:

[0025] Step 1, preparation of carbon nanoparticles containing carboxyl and hydroxyl groups on the surface;

[0026] Step 2: Preparation of a mixed gel solution: uniformly mix accurately measured PVA resin, carbon nanotubes with carboxyl and hydroxyl groups on their surfaces, plasticizer, and pure water, raise the temperature to 80-95°C and stir for 2-4 hours, then add a crosslinker aqueous solution according to the ratio and stir for 2-4 hours to prepare a mixed gel solution;

[0027] Step three, cool the mixed gel solution in step two to 50-65°C and add it to the inside of the slit coater, set the die temperature to 60-120°C, the discharge thickness to 65-350 microns, the dry film thickness to 20-50 microns, the solution viscosity to 4000-6000 centipoise, and the solid content to 15-30%, and prepare a chemically cross-linked carbon nanotube electromagnetic shielding degradable film through a one-step method.

[0028] The synthesis technology of the electromagnetic shielding degradable film of the present invention is relatively low in difficulty, has little pollution, and is easy to realize large-scale batch industrial production.

[0029] In summary, this application has the following advantages:

[0030] 1. The PVA film of the present invention has antibacterial, anti-mildew, electromagnetic shielding and antistatic effects, and is used in the field of medical nonwovens to improve the safety of medical staff.

[0031] 2. The synthesis technology of the metal ion coordination type antibacterial, mildew proof and electromagnetic shielding degradable film in the present invention is relatively low in difficulty and has little pollution, which facilitates large-scale batch industrial production, thereby reducing the cost of using nano antibacterial agents, mildew proof agents and electromagnetic shielding materials, and enhancing the market competitiveness of chemically cross-linked carbon nanotube electromagnetic shielding degradable film.

[0032] 3. The organic esterification-based degradable film synthesis technology for electromagnetic shielding in the present invention is relatively easy to synthesize, has low pollution, and is easy to implement in large-scale industrial production. This can reduce the cost of using nano-antibacterial agents, mildew inhibitors, and electromagnetic shielding materials, and enhance the market competitiveness of degradable films for medical and health use. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 1 is a diagram showing the reaction equation of PVA-OH and HO-CNTs-COOH reacting with a cross-linking agent in the embodiment. DETAILED DESCRIPTION

[0034] In order to further understand the creativity and technical advancement of the present invention, the preferred embodiments of the present invention are discussed in detail below in conjunction with examples and comparative examples.

[0035] Example: A chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 1-4 parts of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 20-28 parts of PVA resin, 2-4 parts of plasticizer, 160-240 parts of pure water, and 1-10 parts of metal ion cross-linking agent.

[0036] The plasticizer is at least one of glycerol, ethylene glycol, propylene glycol, and butylene glycol.

[0037] The alcoholysis degree of PVA is ≥79%, and the polymerization degree is 300-2400. The PVA resin can be selected from at least one of PVA-2499, PVA-1788, PVA-1799, and PVA-2388. Preferably, the PVA resin is PVA-2499.

[0038] The crosslinking agent is a metal ion crosslinking agent or an organic small molecule carrying at least one carboxyl or aldehyde functional group. The organic small molecule carrying at least one carboxyl or aldehyde functional group is any one of malonic acid, 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,5-glutaric acid, 1,7-pimelic acid, 1,9-nonanedioic acid, and 1,10-decanedioic acid.

[0039] The metal cation generated in the metal ion crosslinker is Fe 3+ 、Fe 2+ 、Cu 2+ 、Cu + 、Zn 2+ 、Mn 2+ , Pb 2+ 、Ag + 、Al 3 + 、Au + At least one of the metal ion crosslinking agent generates anions of SO4 2- 、Cl - 、NO3 - Specifically, the metal ion crosslinking agent is at least one of copper sulfate, copper chloride, copper nitrate, manganese sulfate, manganese chloride, manganese nitrate, zinc sulfate, zinc chloride, zinc nitrate, ferric chloride, ferric nitrate, aluminum sulfate, aluminum nitrate, lead chloride, lead nitrate, lead acetate, silver nitrate, and chloroauric acid.

[0040] Preferably, the metal cation generated in the metal ion crosslinking agent is Fe 3+ 、Cu 2+ 、Al 3+、Ag + At least one of, specifically, the metal ion crosslinking agent is at least one of copper sulfate, copper chloride, copper nitrate, ferric chloride, ferric nitrate, aluminum sulfate, aluminum nitrate, and silver nitrate.

[0041] When the crosslinking agent is a metal ion crosslinking agent, the PVA-OH and HO-CNTs-COOH undergo esterification reaction with the metal ion crosslinking agent to form a composite process. Figure 1 . Inorganic metal salts dissociate into metal ions Me n+ It exists in the form of coordination inside the PVA degradable film, which can improve the antibacterial, anti-mildew, electromagnetic shielding and antistatic effects of the PVA film.

[0042] When the crosslinking agent is a metal ion crosslinking agent, PVA-OH and HO-CNTs-COOH undergo esterification reaction with organic small molecules carrying at least one carboxyl or aldehyde functional group. Figure 1 The chemical cross-linking agent is an organic small molecule carrying at least one carboxyl or aldehyde functional group. In the solution, PVA-OH and HO-CNTs-COOH are compounded through esterification reaction with the chemical cross-linking agent, which can improve the electromagnetic shielding and antistatic effects of the PVA film.

[0043] The preparation method of carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface is as follows: using a strong acid or a strong oxidant or a Fenton reagent or plasma to treat carbon nanotubes (CNTs), the carbon nanotubes are single-walled carbon nanotubes and / or multi-walled carbon nanotubes, at least carboxyl groups -COOH and hydroxyl groups -OH functional groups are introduced into the surface of the CNTs, and the carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface are modified. That is, the obtained carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface are single-walled carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface and / or multi-walled carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface.

[0044] Carbon nanotubes with surface carboxyl and hydroxyl groups include carboxyl groups (COOH) and hydroxyl groups (OH), and also include at least one of amino groups (NH2), thiol groups (SH), aldehyde groups (CHO), and epoxy groups (CH(O)CH-). Specifically, 10g of carbon nanotubes (CNTs) were added to 100mL of a solution containing a strong acid, strong oxidant, or Fenton's reagent, stirred for 2-4 hours, and then directly centrifuged, washed, and dried to obtain carbon nanotubes with surface carboxyl and hydroxyl groups.

[0045] Example 1: A chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 2g of anhydrous copper sulfate, 24g of PVA-2499 resin, 1g of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g of glycerol and 200g of pure water.

[0046] A chemically cross-linked carbon nanotube degradable film for electromagnetic shielding comprises the following steps:

[0047] See also Figure 1 Step 1: Preparation of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces: 98% H2SO4 and 65% HNO3 were mixed in a volume ratio of 3:1 to form a mixed acid. 100 mL of the mixed acid was added to 10 g of carbon nanotubes (CNTs model NC7000, sourced from Nanocyl SA, Belgium). The mixture was ultrasonically stirred for 4 hours, followed by direct centrifugation, washing, and drying to obtain carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH).

[0048] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 1 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed uniformly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 2 g of anhydrous copper sulfate was dissolved in 18 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was stirred at 200 rpm for 2 hours to obtain a mixed gel solution.

[0049] Step three, cool the mixed gel solution in step two to 60°C and add it into the slit coater, set the die temperature to 120°C, the discharge thickness to 250 μm, the dry film thickness to 50 μm, the solution viscosity to 5000 centipoise, and the solid content to 20%, and prepare a chemically cross-linked carbon nanotube electromagnetic shielding degradable film through a one-step method.

[0050] The difference between Example 2 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 2g of anhydrous copper sulfate, 24g of PVA-2499 resin, 2g of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g of glycerol and 200g of pure water.

[0051] The difference in the preparation method of the chemically cross-linked carbon nanotube degradable film for electromagnetic shielding lies in: Step 2, preparation of the mixed gel solution: 24g of PVA-2499, 2g of carbon nanotubes with carboxyl and hydroxyl groups on the surface prepared in Step 1 (HO-CNTs-COOH), 4g of glycerol and 200g of pure water are mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A, then 2g of anhydrous copper sulfate is dissolved in 18g of pure water to form a copper sulfate aqueous solution, 20g of the copper sulfate aqueous solution is added to the mixed solution A, and mixed at a stirring speed of 200rpm for 3 hours to obtain a mixed gel solution.

[0052] The difference between Example 3 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 2g anhydrous copper sulfate, 24g PVA-2499 resin, 4g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0053] The difference in the preparation method of the chemically cross-linked carbon nanotube degradable film for electromagnetic shielding lies in: Step 2, preparation of the mixed gel solution: 24g of PVA-2499, 4g of carbon nanotubes with carboxyl and hydroxyl groups on the surface prepared in Step 1 (HO-CNTs-COOH), 4g of glycerol and 200g of pure water are mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A, then 2g of anhydrous copper sulfate is dissolved in 18g of pure water to form a copper sulfate aqueous solution, 20g of the copper sulfate aqueous solution is added to the mixed solution A, and mixed at a stirring speed of 200rpm for 4 hours to obtain a mixed gel solution.

[0054] The difference between Example 4 and Example 2 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 1g of anhydrous copper sulfate, 24g of PVA-2499 resin, 2g of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g of glycerol and 200g of pure water.

[0055] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0056] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 2 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 1 g of anhydrous copper sulfate was dissolved in 19 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0057] The difference between Example 5 and Example 2 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 4g anhydrous copper sulfate, 24g PVA-2499 resin, 2g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0058] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0059] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 2 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 4 g of anhydrous copper sulfate was dissolved in 16 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0060] The difference between Example 6 and Example 2 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 6g of anhydrous copper sulfate, 24g of PVA-2499 resin, 2g of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g of glycerol and 200g of pure water.

[0061] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0062] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499 (degree of polymerization 2400, degree of alcoholysis ≥99%, purity >98.5%, Anhui Wanwei High-tech Materials Co., Ltd.), 2 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85° C. and stirred for 4 hours to obtain a mixed solution A. Subsequently, 6 g of anhydrous copper sulfate was dissolved in 24 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0063] The difference between Example 7 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 8g of anhydrous copper sulfate, 24g of PVA-2499 resin, 2g of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g of glycerol and 200g of pure water.

[0064] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0065] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 2 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 8 g of anhydrous copper sulfate was dissolved in 32 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0066] The difference between Example 8 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 10g anhydrous copper sulfate, 24g PVA-2499 resin, 2g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0067] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0068] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 2 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 10 g of anhydrous copper sulfate was dissolved in 30 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0069] The difference between Example 9 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 6g of anhydrous copper sulfate, 24g of PVA-2499 resin, 4g of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g of glycerol and 200g of pure water.

[0070] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0071] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 6 g of anhydrous copper sulfate was dissolved in 24 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0072] The difference between Example 10 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 8g of anhydrous copper sulfate, 24g of PVA-2499 resin, 4g of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g of glycerol and 200g of pure water.

[0073] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0074] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 8 g of anhydrous copper sulfate was dissolved in 32 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was stirred at 200 rpm for 4 hours to obtain a mixed gel solution.

[0075] The difference between Example 11 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 10g anhydrous copper sulfate, 24g PVA-2499 resin, 4g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0076] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0077] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 4 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 10 g of anhydrous copper sulfate was dissolved in 30 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was stirred at 200 rpm for 4 hours to obtain a mixed gel solution.

[0078] The difference between Example 12 and Example 9 is that anhydrous copper sulfate is replaced by manganese sulfate.

[0079] The difference between Example 13 and Example 9 is that anhydrous copper sulfate is replaced by zinc sulfate.

[0080] The difference between Example 14 and Example 9 is that anhydrous copper sulfate is replaced by ferric nitrate.

[0081] The difference between Example 15 and Example 9 is that anhydrous copper sulfate is replaced by aluminum nitrate.

[0082] The difference between Example 16 and Example 9 is that anhydrous copper sulfate is replaced by silver nitrate.

[0083] The difference between Example 17 and Example 9 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 1g silver nitrate and 5g ferric nitrate, 24g PVA-2499 resin, 4g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0084] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0085] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 4 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 1 g of silver nitrate and 5 g of ferric nitrate were dissolved in 24 g of pure water to form a copper sulfate solution. 20 g of the copper sulfate solution was added to the mixed solution A, and the mixture was stirred at 200 rpm for 4 hours to obtain a mixed gel solution.

[0086] The difference between Example 18 and Example 9 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 1g silver nitrate, 2g anhydrous copper sulfate and 3g ferric nitrate, 24g PVA-2499 resin, 4g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0087] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0088] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 1 g of silver nitrate, 2 g of anhydrous copper sulfate, and 3 g of ferric nitrate were dissolved in 24 g of pure water to form a copper sulfate solution. 20 g of the copper sulfate solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0089] The difference between Example 19 and Example 9 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 1g silver nitrate, 2g aluminum nitrate and 3g ferric nitrate, 24g PVA-2499 resin, 4g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0090] The difference between the preparation methods of chemically cross-linked carbon nanotube degradable films for electromagnetic shielding is:

[0091] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 1 g of silver nitrate, 2 g of copper nitrate, and 3 g of ferric nitrate were dissolved in 24 g of pure water to form a copper sulfate solution. 20 g of the copper sulfate solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 4 hours to obtain a mixed gel solution.

[0092] The difference between Example 20 and Example 9 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 1g silver nitrate, 2g aluminum nitrate and 3g anhydrous copper sulfate, 24g PVA-2499 resin, 4g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0093] The difference between the preparation methods of chemically cross-linked carbon nanotube degradable films for electromagnetic shielding is:

[0094] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499, 4 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85°C and stirred for 4 hours to obtain a mixed solution A. Subsequently, 1 g of silver nitrate, 2 g of copper nitrate, and 3 g of anhydrous copper sulfate were dissolved in 24 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was stirred at 200 rpm for 4 hours to obtain a mixed gel solution.

[0095] Example 21: A chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is made of 2g of malonic acid, 24g of PVA-2499, 2g of carbon nanotubes with carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4g of glycerol and 200g of pure water.

[0096] The preparation method of the chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is as follows:

[0097] Step 1: Add 24 parts of PVA, 2 g of carbon nanotubes with carboxyl and hydroxyl groups on their surfaces (HO-CNTs-COOH) prepared in Step 1, 4 g of glycerol, and 2 g of malonic acid to 200 g of pure water, raise the temperature from room temperature to 85°C, and stir at 200 rpm for 4 hours to obtain a mixed solution A, thereby preparing a mixed gel solution.

[0098] Step 2: Cool the mixed gel solution in step 1 to 60°C and add it into a slit coater. The die temperature is set to 120°C, the discharge thickness is set to 250 μm, the dry film thickness is set to 50 μm, the solution viscosity is set to 5000 centipoise, and the solid content is set to 20%. A chemically cross-linked carbon nanotube electromagnetic shielding degradable film is prepared through a one-step method.

[0099] The difference between Example 22 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 2 g of malonic acid, 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol and 200 g of pure water.

[0100] The difference between Example 23 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 4 g of malonic acid, 24 g of PVA-2499, 2 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol and 200 g of pure water.

[0101] The difference between Example 24 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 4 g of malonic acid, 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol and 200 g of pure water.

[0102] The difference between Example 25 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 6 g of malonic acid, 24 g of PVA-2499, 2 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol and 200 g of pure water.

[0103] The difference between Example 26 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 6 g of malonic acid, 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol and 200 g of pure water.

[0104] The difference between Example 27 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 8 g of malonic acid, 24 g of PVA-2499, 2 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol and 200 g of pure water.

[0105] The difference between Example 28 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 8 g of malonic acid, 24 g of PVA-2499, 4 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol and 200 g of pure water.

[0106] The difference between Example 29 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 10g of malonic acid, 24g of PVA-2499, 2g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4g of glycerol and 200g of pure water.

[0107] The difference between Example 30 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 10g of malonic acid, 24g of PVA-2499, 4g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4g of glycerol and 200g of pure water.

[0108] The difference between Example 31 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 10g of 1,5-pentanedioic acid, 24g of PVA-2499, 4g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4g of glycerol and 200g of pure water.

[0109] The difference between Example 32 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 10g of 1,6-adipic acid, 24g of PVA-2499, 4g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface prepared in step 1 (HO-CNTs-COOH), 4g of glycerol and 200g of pure water.

[0110] The difference between Comparative Example 1 and Example 1 is that a degradable film is made from 24g of PVA-2499 resin, 4g of glycerol and 200g of pure water. The preparation method of the degradable film is as follows:

[0111] Step 1: Preparation of mixed gel solution: 24 g PVA-2499 (degree of polymerization 2400, alcoholysis degree ≥99%, purity >98.5%, Anhui Wanwei High-tech Materials Co., Ltd.), 4 g glycerol and 200 g pure water were mixed evenly, heated to 85° C. and stirred for 4 hours to obtain a mixed gel solution;

[0112] Step 2: Cool the mixed gel solution in step 1 to 60°C and add it into a slit coater. The die temperature is set to 120°C, the discharge thickness is set to 250 μm, the dry film thickness is set to 50 μm, the solution viscosity is set to 5000 centipoise, and the solid content is set to 20%. A chemically cross-linked carbon nanotube electromagnetic shielding degradable film is prepared through a one-step method.

[0113] The difference between Comparative Example 2 and Comparative Example 1 is that a degradable film is made from 2 g of anhydrous copper sulfate, 24 g of PVA-2499, 4 g of glycerol and 200 g of pure water.

[0114] The difference between the preparation methods of the degradable film is: Step 1, preparation of the mixed gel solution: 24g PVA-2499 (polymerization degree 2400, alcoholysis degree ≥99%, purity >98.5%, Anhui Wanwei High-tech Materials Co., Ltd.), 4g glycerol and 200g pure water are accurately measured and evenly mixed, heated to 85°C and stirred for 4 hours to obtain a mixed solution A, then 2g anhydrous copper sulfate is dissolved in 8g pure water to form a copper sulfate aqueous solution, 20g of the copper sulfate aqueous solution is added to the mixed solution A, and mixed at a stirring speed of 200rpm for 2 hours to obtain a mixed gel solution.

[0115] The difference between Comparative Example 3 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 24g PVA-2499 resin, 1g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0116] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0117] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499 (degree of polymerization 2400, degree of alcoholysis ≥99%, purity >98.5%, Anhui Wanwei High-tech Materials Co., Ltd.), 1 g of carbon nanotubes with surface carboxyl and hydroxyl groups (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol, and 200 g of pure water were mixed uniformly, heated to 85° C., and stirred for 4 hours to obtain a mixed gel solution.

[0118] The difference between Comparative Example 4 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 2g anhydrous copper sulfate, 24g PVA-2499 resin, 0.5g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0119] The difference in the preparation method of chemically cross-linked carbon nanotube degradable film for electromagnetic shielding is:

[0120] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499 (degree of polymerization 2400, degree of alcoholysis ≥99%, purity >98.5%, Anhui Wanwei High-tech Materials Co., Ltd.), 0.5 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85° C. and stirred for 4 hours to obtain a mixed solution A. Subsequently, 2 g of anhydrous copper sulfate was dissolved in 18 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 2 hours to obtain a mixed gel solution.

[0121] The difference between Comparative Example 5 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 0.5g anhydrous copper sulfate, 24g PVA-2499 resin, 1g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0122] The difference between the preparation methods of chemically cross-linked carbon nanotube degradable films for electromagnetic shielding is:

[0123] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499 (degree of polymerization 2400, degree of alcoholysis ≥99%, purity >98.5%, Anhui Wanwei High-tech Materials Co., Ltd.), 1 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85° C. and stirred for 4 hours to obtain a mixed solution A. Subsequently, 0.5 g of anhydrous copper sulfate was dissolved in 19.5 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 2 hours to obtain a mixed gel solution.

[0124] The difference between Comparative Example 6 and Example 1 is that a chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 0.5g anhydrous copper sulfate, 24g PVA-2499 resin, 0.5g carbon nanotubes with carboxyl and hydroxyl groups on the surface, 4g glycerol and 200g pure water.

[0125] The difference between the preparation methods of chemically cross-linked carbon nanotube degradable films for electromagnetic shielding is:

[0126] Step 2, preparation of a mixed gel solution: 24 g of PVA-2499 (degree of polymerization 2400, degree of alcoholysis ≥99%, purity >98.5%, Anhui Wanwei High-tech Materials Co., Ltd.), 0.5 g of carbon nanotubes containing carboxyl and hydroxyl groups on the surface (HO-CNTs-COOH) prepared in step 1, 4 g of glycerol, and 200 g of pure water were mixed evenly, heated to 85° C. and stirred for 4 hours to obtain a mixed solution A. Subsequently, 0.5 g of anhydrous copper sulfate was dissolved in 19.5 g of pure water to form a copper sulfate aqueous solution. 20 g of the copper sulfate aqueous solution was added to the mixed solution A, and the mixture was mixed at a stirring speed of 200 rpm for 2 hours to obtain a mixed gel solution.

[0127] The difference between Comparative Example 7 and Example 21 is that the chemically cross-linked carbon nanotube electromagnetic shielding degradable film is made of 10 g of malonic acid, 24 g of PVA-2499, 4 g of glycerol and 200 g of pure water.

[0128] Performance test: 1. Test method for antibacterial rate: QB / T 2591-2003 "Test method for antibacterial performance and antibacterial effect of antibacterial plastics" tests the antibacterial rate of the film. Pour about 15mL of culture medium into a sterile culture dish in a sterile manner. After the culture medium solidifies, use a sterile pipette to draw 100μL of bacterial suspension on the surface of the culture medium. Use a sterile coating rod to evenly spread the added bacterial suspension, and place a sterile sample in the culture dish. Bacteria are cultured in an incubator at 37°C for 24 hours, and molds are cultured in an incubator at 28°C for 48 hours. Experiments are conducted on Escherichia coli, Staphylococcus aureus, Candida albicans and Penicillium respectively. The judgment standard is that when the inhibition value is ≥2 or the inhibition rate is ≥99%, it proves that it has an antibacterial effect. 2. Test method for antistatic level: Use a dual-electric four-probe square resistance resistivity tester to test the surface resistance of the membrane material. The surface resistance of the tested membrane material is <10 9 Ohm, it is considered that it has antistatic properties and is OK. The surface resistance of the test film is >10 9 3. Test method for water vapor transmission rate: According to GB / T 19082-2023, the water vapor transmission rate is ≥550g / m 2 1 / 24h is recorded as Pass, otherwise it is recorded as NG. 4. Hydrostatic Pressure Test Method: Measured in accordance with GB / T 19082-2023. A hydrostatic pressure ≥1500mmH20 is recorded as Pass, otherwise it is recorded as NG. 5. Mildew Resistance Test Method: Measured in accordance with GB / T 24346-2009, Evaluation of Mildew Resistance of Textiles. 6. Electromagnetic Shielding Performance Test Method: Measured in accordance with GB / T 23463-2009, test band X-band (8.2-12.4 GHz).

[0129] Table 1: Antibacterial and mildew-proof test parameters of the degradable films in Examples 1-20 and Comparative Examples 1-6

[0130] Candida albicans antibacterial rate % Escherichia coli antibacterial rate% Antibacterial rate of Staphylococcus aureus % Penicillium antibacterial rate% Mildew resistance grade / level Example 1 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 2 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 3 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 4 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 5 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 6 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 7 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 8 ＞99.9 ＞99.9 ＞99.9 ＞99.9 0 Example 9 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 10 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 11 ＞99.9 ＞99.9 ＞99.9 ＞99.9 0 Example 12 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 13 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 14 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 15 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 16 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 17 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 18 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 19 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Example 20 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Comparative Example 1 10.5 15.1 18.5 14.1 4 Comparative Example 2 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Comparative Example 3 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Comparative Example 4 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Comparative Example 5 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1 Comparative Example 6 ＞99.9 ＞99.9 ＞99.9 ＞99.9 1

[0131] Table 2: Physical and chemical performance test parameters of the degradable films in Examples 1-20 and Comparative Examples 1-6

[0132] Electromagnetic shielding effectiveness (dB) After washing 10 times (dB) After washing 20 times (dB) Antistatic grade (NG / OK) Hydrostatic performance (NG / Pass) Example 1 13.1 12.1 10.2 OK Pass Example 2 17.2 16.8 15.8 OK Pass Example 3 22.2 21.4 20.1 OK Pass Example 4 15.2 14.1 13.0 OK Pass Example 5 19.3 18.6 17.4 OK Pass Example 6 24.5 23.7 22.3 OK Pass Example 7 28.9 27.8 26.9 OK Pass Example 8 31.2 30.4 29.6 OK Pass Example 9 36.7 35.8 34.5 OK Pass Example 10 42.3 41.2 40.4 OK Pass Example 11 44.8 42.8 40.3 OK Pass Example 12 36.2 35.3 34.0 OK Pass Example 13 37.0 36.5 35.8 OK Pass Example 14 36.8 36.0 35.7 OK Pass Example 15 36.2 35.4 34.5 OK Pass Example 16 37.1 36.2 35.7 OK Pass Example 17 36.9 36.2 35.6 OK Pass Example 18 36.9 36.4 36.0 OK Pass Example 19 36.7 36.2 35.3 OK Pass Example 20 36.4 36.2 36.1 OK Pass Example 21 15.2 14.7 14.5 OK Pass Example 22 20.2 19.5 19.2 OK Pass Example 23 15.3 14.6 14.2 OK Pass Example 24 20.3 19.5 19.2 OK Pass Example 25 15.4 14.7 14.1 OK Pass Example 26 20.6 19.9 19.1 OK Pass Example 27 15.5 14.8 14.2 OK Pass Example 28 20.4 19.4 19.2 OK Pass Example 29 15.4 14.7 14.4 OK Pass Example 30 21.1 20.5 19.8 OK Pass Example 31 20.7 19.9 19.1 OK Pass Example 32 20.8 20.0 19.4 OK Pass Comparative Example 1 0.0 0.0 0.0 NG Pass Comparative Example 2 5.0 4.5 4.2 OK Pass Comparative Example 3 9.1 8.6 8.0 OK Pass Comparative Example 4 9.8 9.2 9.0 OK Pass Comparative Example 5 11.8 10.7 9.5 OK Pass Comparative Example 6 8.7 8.0 7.2 OK Pass Comparative Example 7 0.0 0.0 0.0 NG Pass

[0133] It can be seen from Examples 1-20 and Comparative Examples 1-6 and Table 1-2 that the copper ion coordination antibacterial, mildew-proof and electromagnetic shielding degradable film of the present invention has antibacterial, mildew-proof, electromagnetic shielding and antistatic effects, and is used in the field of medical non-woven fabrics to reduce the risk of bacterial infection and static electricity for medical staff.

[0134] Combining Examples 1-20 and Comparative Examples 1-6 and Table 1-2, it can be seen that, considering the comprehensive production cost and physical and chemical properties, the antibacterial, mildew-proof and electromagnetic shielding degradable film for traditional Chinese medicine and health use in Example 11 is an industrial mass production solution.

[0135] In summary, in the present invention, carbon nanotubes are carboxylated and modified. The carboxyl-modified carbon nanotubes compete with the hydroxyl groups on the PVA resin for coordination reaction with metal ions, and the carbon nanotubes are grafted onto the sides of the PVA molecular chains. This improves the dispersion uniformity of the carbon nanotubes and the connection stability with the PVA molecular chains, and gives the prepared film good degradability, antistatic properties, and antibacterial and mildew-proof properties. The metal ions and carbon nanotubes produce a synergistic effect, giving the prepared film better electromagnetic shielding properties. The EMI performance SE in the X-band (8.2-12.4 GHz) is 17-45dB, which can be used in the field of medical non-woven fabrics to improve the safety of medical staff.

[0136] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A chemically cross-linked carbon nanotube degradable film for electromagnetic shielding, characterized by: The invention is prepared by the following raw materials in parts by weight: 1-4 parts of carbon nanotubes with carboxyl and hydroxyl groups on the surface, 20-28 parts of PVA resin, 2-4 parts of plasticizer, 160-240 parts of pure water, and 1-10 parts of a cross-linking agent; the cross-linking agent is a metal ion cross-linking agent or an organic small molecule carrying at least one carboxyl or aldehyde functional group; the metal cation generated in the metal ion cross-linking agent is Fe 3+ 、Fe 2+ 、Cu 2+ 、Cu + 、Zn 2+ 、Mn 2 + , Pb 2+ 、Ag + 、Al 3+ 、Au + At least one of .

2. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 1, characterized in that: The metal ion crosslinking agent is at least one of copper sulfate, copper chloride, copper nitrate, manganese sulfate, manganese chloride, manganese nitrate, zinc sulfate, zinc chloride, zinc nitrate, ferric chloride, ferric nitrate, aluminum sulfate, aluminum nitrate, lead chloride, lead nitrate, lead acetate, silver nitrate, and chloroauric acid.

3. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 2, characterized in that: The metal cation generated in the metal ion crosslinking agent is Fe 3+ 、Cu 2+ 、Al 3+ 、Ag + At least one of the metal ion cross-linking agent is copper sulfate, copper chloride, copper nitrate, ferric chloride, ferric nitrate, aluminum sulfate, aluminum nitrate, and silver nitrate.

4. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 1, characterized in that: The carbon nanotubes containing carboxyl and hydroxyl groups on the surface include carboxyl groups -COOH and hydroxyl groups -OH, and also include at least one of amino groups -NH2, thiol groups -SH, aldehyde groups -CHO, and epoxy groups -CH(O)CH-.

5. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 4, characterized in that: The preparation method of the carbon nanotubes containing carboxyl and hydroxyl groups on the surface is as follows: using a strong acid or a strong oxidant or a Fenton reagent or plasma to treat carbon nanotubes (CNTs), at least carboxyl -COOH and hydroxyl -OH functional groups are introduced into the surface of the CNTs, and the carbon nanotubes containing carboxyl and hydroxyl groups on the surface are modified.

6. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 5, characterized in that: The carbon nanotubes are single-walled carbon nanotubes and / or multi-walled carbon nanotubes; the carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface are single-walled carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface and / or multi-walled carbon nanotubes containing carboxyl groups and hydroxyl groups on the surface.

7. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 1, characterized in that: The organic small molecule carrying at least one carboxyl or aldehyde functional group is any one of malonic acid, 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,5-pentanedioic acid, 1,7-pimelic acid, 1,9-nonanedioic acid, and 1,10-decanedioic acid.

8. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 1, characterized in that: The alcoholysis degree of the PVA is ≥79%, and the polymerization degree is 300-2400. The PVA includes at least one of PVA-2499, PVA-1788, PVA-1799, and PVA-2388. The plasticizer is one or more combinations of glycerol, ethylene glycol, propylene glycol, and butylene glycol.

9. The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to claim 3, characterized in that: The chemically cross-linked carbon nanotube degradable film for electromagnetic shielding has an EMI efficiency SE of 17-45 dB in the X-band, and the X-band is 8.2-12.4 GHz.

10. A method for preparing a chemically cross-linked carbon nanotube degradable film for electromagnetic shielding according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1, preparation of carbon nanotubes with carboxyl and hydroxyl groups on the surface; Step 2: Preparation of a mixed gel solution: uniformly mix accurately measured PVA resin, carbon nanotubes with carboxyl and hydroxyl groups on their surfaces, plasticizer, and pure water, raise the temperature to 80-95°C and stir for 2-4 hours, then add a crosslinker aqueous solution according to the ratio and stir for 2-4 hours to prepare a mixed gel solution; Step three, cool the mixed gel solution in step two to 50-65°C and add it to the inside of the slit coater, set the die temperature to 60-120°C, the discharge thickness to 65-350 microns, the dry film thickness to 20-50 microns, the solution viscosity to 4000-6000 centipoise, and the solid content to 15-30%, and prepare a chemically cross-linked carbon nanotube electromagnetic shielding degradable film through a one-step method.

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