Preparation method and application of multifunctional polyethylene film

Abstract

The application discloses a preparation method and application of a multifunctional polyethylene film, and comprises the following steps: 1) under the action of a peroxide initiator and optionally an auxiliary, polyethylene resin is melt-reacted with an acrylate to prepare a polyethylene-acrylate copolymer; 2) inorganic fillers, a coupling agent and a long carbon chain quaternary ammonium salt are mixed in a dispersion medium, the pH is adjusted to 2-7, high-speed stirring is carried out at a treatment temperature of 20-80 DEG C for 2-12 h, and the solid is separated to obtain modified fillers; 3) a transition metal carbide is high-speed mixed with the polyethylene-acrylate copolymer prepared in step 1), the modified fillers prepared in step 2) and optionally an auxiliary, and then is molded to prepare the multifunctional polyethylene film.

Description

Technical Field

[0001] This invention relates to a multifunctional polyethylene film, and more particularly to a method for preparing and applying a multifunctional polyethylene film. Background Technology

[0002] Polyethylene, a thermoplastic resin obtained by polymerizing ethylene, possesses excellent molding and processing properties, corrosion resistance, and impact resistance, and is widely used in pressure vessels, petrochemicals, electrical equipment, food packaging, and other fields. Meanwhile, with the rapid development of electronic communication technology, electromagnetic interference and radiation pose serious threats to information security and human health, thus placing higher demands on electromagnetic shielding materials. However, traditional electromagnetic shielding materials are mainly metals such as aluminum and copper, which have problems such as high density and large volume, making them difficult to widely apply in electronic communication and human electromagnetic shielding protection. Currently, existing technologies struggle to produce polymer materials that combine good electromagnetic shielding performance with excellent gas barrier properties.

[0003] Patent CN111892781A reports a method for preparing an Mxene / ultra-high molecular weight polyethylene composite material. The method uses the two-dimensional transition metal material MXene as a conductive filler, dispersed on the surface of polydopamine-modified ultra-high molecular weight polyethylene, thus improving the corrosion resistance of the electromagnetic shielding material. However, ultra-high molecular weight polyethylene has extremely high viscosity and poor fluidity in the molten state, with a melt flow rate almost zero. This makes it difficult to disperse the filler, resulting in poor molding and processing performance and high requirements for processing equipment. This limits the amount of two-dimensional transition metal material used in the resin matrix, leading to insignificant enhancement effects on the electromagnetic shielding performance and mechanical strength of the polymer material. Furthermore, the gas barrier properties of the polymer material provided by this patent are relatively poor, failing to achieve the multifunctionality of the polymer material. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for preparing a multifunctional polyethylene film and its application. The method for preparing the multifunctional polyethylene film provided by this invention enables the resin to be easily molded and processed while simultaneously constructing a compatible system between inorganic nanoparticles and the resin matrix. This improves the dispersibility of inorganic fillers in the resin matrix, giving the polymer excellent electromagnetic shielding properties, gas barrier properties, and mechanical strength, thus realizing the multifunctionality of the polymer material.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a multifunctional polyethylene film includes the following steps:

[0007] 1) Under the action of a peroxide initiator and optional additives, polyethylene resin and acrylate are melt-reacted to prepare a polyethylene-acrylate copolymer;

[0008] 2) Mix the inorganic filler, coupling agent, and long-chain quaternary ammonium salt in a dispersion medium, adjust the pH to 2-7, preferably 2-5, and stir at high speed for 2-12 hours, preferably 5-10 hours, at a treatment temperature of 20-80℃, preferably 30-75℃. Separate the solid to obtain the modified filler.

[0009] 3) The transition metal carbide is mixed at high speed with the polyethylene-acrylate copolymer obtained in step 1), the modified filler obtained in step 2), and optional additives, and then molded to obtain a multifunctional polyethylene film.

[0010] As a preferred embodiment, in step 1), the amount of acrylate used is 0.1-1 wt%, preferably 0.2-0.8 wt%, more preferably 0.3-0.7 wt%, based on the mass of polyethylene resin;

[0011] Preferably, the acrylate is one or more selected from ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, methyl methacrylate, and butyl methacrylate.

[0012] As a preferred embodiment, in step 1), the amount of the peroxide initiator is 0.01 to 0.5 wt%, preferably 0.03 to 0.3 wt%, more preferably 0.05 to 0.2 wt%, based on the mass of polyethylene resin;

[0013] Preferably, the peroxide initiator is selected from one or more of benzoyl peroxide, tert-butyl peroxide, dicumyl peroxide, diisopropyl peroxide, and di-tert-butyl peroxide.

[0014] As a preferred embodiment, the polyethylene resin is one or more of high-density polyethylene, medium-density polyethylene, and low-density polyethylene;

[0015] Preferably, the molecular weight of the polyethylene resin is 10 × 10⁻⁶. 4 ~80×10 4 g / mol, preferably 40×10 4 ~70×10 4 g / mol.

[0016] As a preferred embodiment, the reaction conditions in step 1) are: temperature 140℃~260℃, preferably 160℃~230℃, and rotation speed 20~60rpm / min, preferably 30~40rpm / min.

[0017] Preferably, in step 1), the raw materials are mixed at a high speed of 1000-5000 rpm / min for 10-30 min, and then melted and reacted.

[0018] As a preferred embodiment, the inorganic filler is a non-metallic nanoparticle, preferably one or more of the following: reduced graphene oxide, graphene oxide, montmorillonite, mica sheets, carbon nanotubes, silicon carbide nanoparticles, silicon powder, and silicon nanowires.

[0019] Preferably, the coupling agent is one or more of silane coupling agents, titanate coupling agents, zirconate coupling agents, and aluminate coupling agents, and more preferably one or more of triethoxyvinylsilane, γ-aminopropyltriethoxysilane, allyltrichlorosilane, tetrabutyl titanate, isopropyl titanate, and tetra-n-propyl zirconate.

[0020] Preferably, the long-chain quaternary ammonium salt is selected from one or more of hexadecyltrimethylammonium bromide, trimethyloctadecylammonium bromide, dihexadecyldimethylammonium bromide, dioctadecyldimethylammonium chloride, and didodecyldimethylammonium bromide.

[0021] As a preferred embodiment, in step 2), the mass ratio of the inorganic filler, coupling agent, and long-chain quaternary ammonium salt is (1-2.5):(0.3-0.7):1.

[0022] Preferably, the dispersion medium in step 2) is water, ethanol, or a blend thereof, and the amount of dispersion medium added can be 0.5 to 10 times the total mass of the raw materials in this step. More preferably, after the raw materials are added to the dispersion medium in step 2), they are mixed evenly at 30 to 80°C and 500 to 5000 rpm / min, and the mixing time is generally 2 to 10 hours.

[0023] Preferably, after the raw materials are stirred and mixed in step 2), the solids can be separated by centrifugation / filtration, and then washed and dried to obtain the modified filler.

[0024] As a preferred embodiment, in step 3), the mass ratio of transition metal carbide, polyethylene-acrylate copolymer, and modified filler is 1:(2-20):(0.1-5), preferably 1:(4-15):(0.1-1).

[0025] Preferably, in step 3), the high-speed mixing conditions can be mixing at 1000-5000 rpm / min for 10-30 min, and the molding temperature is, for example, 140-220℃, preferably 160-200℃, more preferably 170-190℃; the molding pressure is, for example, 1-10 MPa, preferably 3-7 MPa.

[0026] Unless otherwise specified, the pressure referred to in this invention refers to absolute pressure.

[0027] In addition, the transition metal carbides in step 3) can be purchased from commercially available powders, granules, or suspensions, with a particle size of 30-500 nm. If a suspension of transition metal carbides is purchased, it should be filtered first to obtain a solid before being mixed with other raw materials for reaction.

[0028] In a preferred embodiment, the additive is one or more of antioxidants, lubricants, plasticizers, and flame retardants. The amount of additive added can be adjusted based on the conventional addition amount or experience of those skilled in the art. For example, the amount of antioxidant can be 0.03-0.5% of the mass of the blended raw materials, the amount of lubricant can be 0.05-0.8% of the mass of the blended raw materials, the amount of plasticizer can be 0.01-0.5% of the mass of the blended raw materials, and the amount of flame retardant can be 0.08-1.2% of the mass of the blended raw materials.

[0029] This invention also provides an application of a multifunctional polyethylene film prepared by the method described above in the fields of energy storage, electronic communication, food packaging, and biomedicine.

[0030] The method for preparing the multifunctional polymer membrane provided by this invention has the following advantages compared with the prior art:

[0031] 1. This invention obtains a polyethylene-acrylate copolymer containing polar segments by grafting and modifying polyethylene. This material has good compatibility with inorganic fillers, transition metal carbides, etc., which greatly improves the interfacial properties and provides the resin matrix with excellent impact resistance and molding processability.

[0032] 2. The polyethylene membrane provided by this invention is a multifunctional polymer membrane. The transition metal carbides in the material have high specific surface area, excellent conductivity and dielectric properties. When compounded with polymer, they can achieve efficient microwave absorption of lightweight materials. The inorganic filler modified by long-chain quaternary ammonium salt and coupling agent has good compatibility with polymer, which can achieve synergistic reinforcement to improve mechanical strength. At the same time, it can fully extend the diffusion path of gas molecules in the material and reduce permeability, giving it excellent gas barrier properties.

[0033] 3. This multifunctional polyethylene film has the advantages of excellent electromagnetic shielding performance, high gas barrier properties and mechanical strength, and can be widely used in electronic communications, electromagnetic shielding, pressure vessels, food packaging, pipeline transportation and other fields. Detailed Implementation

[0034] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0035] Unless otherwise specified, the raw materials and reagents involved in the following embodiments of the present invention are all purchased from commercially available sources.

[0036] in:

[0037] High-density polyethylene: Grade 23050-A, molecular weight 200,000-500,000, Wanhua Chemical Group Co., Ltd.

[0038] Medium-density polyethylene: Grade YGM091T, molecular weight 200,000-300,000, manufactured by Sinopec Shanghai Petrochemical Co., Ltd.

[0039] Low-density polyethylene: brand name Sanren N220, molecular weight 200,000-500,000, manufactured by Sinopec Shanghai Petrochemical Co., Ltd.

[0040] Linear low-density polyethylene: Grade DFDC 7050LL, molecular weight 100,000-500,000, Wanhua Chemical Group Co., Ltd.

[0041] Reduced graphene oxide: Grade TG1600, specific surface area 300m² 2 / g, Shanxi Coal Chemistry Institute, Chinese Academy of Sciences

[0042] Graphene oxide: thickness 0.55-1.2nm, Zhongke Leiming Technology Co., Ltd.

[0043] Carbon nanotubes: Grade CNT103, diameter 8-15nm, length 50μm, Zhongke Leiming Technology Co., Ltd.

[0044] Silicon carbide nanoparticles: Grade ZH-SiC-01, average particle size 40nm, Anhui Zhonghang Nanotechnology Development Co., Ltd.

[0045] Montmorillonite: Grade PGN, aspect ratio 300-500, average particle size 16-22μm, Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0046] Titanium carbide: 5 g / L aqueous dispersion, Jilin Yiyi Technology Co., Ltd.

[0047] Vanadium carbide: 5 g / L aqueous dispersion, Jilin Yiyi Technology Co., Ltd.

[0048] Molybdenum carbide: 5 g / L aqueous dispersion, Jilin Yiyi Technology Co., Ltd.

[0049] Niobium carbide: 5 g / L aqueous dispersion, Jilin Yiyi Technology Co., Ltd.

[0050] Triethoxyvinylsilane: Grade A-151, molecular weight 190.3, Nanjing Pinning Coupling Agent Co., Ltd.

[0051] Aminopropyltriethoxysilane: Brand KH-550, molecular weight 221.4, Nanjing Pinning Coupling Agent Co., Ltd.

[0052] Trititanate isopropyl ester: PN-130, molecular weight 956.0, Nanjing Pinning Coupling Agent Co., Ltd.

[0053] Tetrabutyl titanate; grade TnBT, molecular weight 340.3, Nanjing Pinning Coupling Agent Co., Ltd.

[0054] Hexadecyltrimethylammonium bromide: Grade B-16, molecular weight 364.4, Xiamen Advanced Technology Co., Ltd.

[0055] Trimethyloctadecylammonium bromide: Grade B-18, molecular weight 392.5, Xiamen Advanced Technology Co., Ltd.

[0056] Dihexadecyldimethylammonium bromide: Grade BD-16, molecular weight 574.9, Xiamen Advanced Technology Co., Ltd.

[0057] Dioctadecyl dimethyl ammonium chloride: Grade AD-18, molecular weight 586.5, Xiamen Advanced Technology Co., Ltd.

[0058] Didodecyl dimethyl ammonium bromide: Grade BD-12, molecular weight 462.6, Xiamen Advanced Technology Co., Ltd.

[0059] The main testing methods involved in the following embodiments of the present invention are as follows:

[0060] Gas barrier performance test: Tested according to GB / T1038~2000 "Gas permeability test method for plastic films and sheets - differential pressure method".

[0061] Mechanical property testing: Tested in accordance with GB / T18743.1~2022 "Determination of impact strength of simply supported beams of thermoplastic pipes - Part 1: General test method".

[0062] Electromagnetic shielding performance test: Tested in accordance with GB / T30142~2013 "Method for measuring the shielding effectiveness of planar electromagnetic shielding materials".

[0063]

Example 1

[0064] Multifunctional polyethylene film was prepared according to the following method:

[0065] (1) High-density polyethylene, hydroxyethyl acrylate, tert-butyl peroxide, antioxidant 1010, and lubricant liquid paraffin were added to a high-speed mixer and mixed for 15 minutes at a stirring speed of 3500 rpm / min. Then, the mixture was added to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder were 165, 190, 215, 215, 215, 225, and 225°C, respectively. The screw speed was 35 rpm / min. After extrusion, the material was traction, water-cooled granulation, and dried to obtain polyethylene-acrylate copolymer.

[0066] The amounts of hydroxyethyl acrylate, tert-butyl peroxide, antioxidant 1010, and lubricant liquid paraffin added are 0.7 wt%, 0.1 wt%, 0.1 wt%, and 0.5 wt% of the mass of high-density polyethylene, respectively.

[0067] Product characterization was performed using infrared spectroscopy, and it was found that at 1740 cm⁻¹... -1 A strong stretching vibration peak of the carbon-oxygen double bond appeared nearby, at 1250 cm⁻¹. -1 The stretching vibration peak of carbon-oxygen single bonds appeared nearby. The melt flow rate test showed that the MFR value of the copolymer was significantly lower than that of the raw material high-density polyethylene, indicating that the acrylate was successfully grafted into the polyethylene chain segment.

[0068] (2) Reduced graphene oxide, triethoxyvinylsilane, and hexadecyltrimethylammonium bromide were added to an ethanol-water mixture (mass ratio 1:1) at a mass ratio of 1.5:0.5:1. The pH was adjusted to 3 with dilute hydrochloric acid. The mixture was then mixed at 60°C and 3500 rpm / min for 7 h. The mixture was then washed, centrifuged, and the solid was collected and ground through an 800-mesh sieve to obtain the modified inorganic filler for later use.

[0069] (3) A 5 g / L titanium carbide aqueous solution was filtered to obtain a filter cake, which was then freeze-dried to constant weight. The titanium carbide filter cake, polyethylene-acrylate copolymer, and modified inorganic filler were added to a high-speed mixer at a mass ratio of 1:5:0.3, and antioxidant 1010 was added at 0.1 wt% of the total mass of the raw materials. The mixture was mixed at 3500 rpm / min for 30 min to obtain a mixture. The mixture was then used to prepare a multifunctional polyethylene film in a molding press at 180℃ and 5 MPa.

[0070]

Example 2

[0071] Multifunctional polyethylene film was prepared according to the following method:

[0072] (1) Medium-density polyethylene, butyl acrylate, dicumyl peroxide, antioxidant 1010, and liquid paraffin lubricant were added to a high-speed mixer and mixed for 20 minutes at a stirring speed of 2500 rpm / min. Then, the mixture was added to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder were 150, 180, 200, 205, 205, 215, and 215°C, respectively. The screw speed was 60 rpm / min. After extrusion, the material was traction, water-cooled granulation, and dried to obtain polyethylene-acrylate copolymer.

[0073] The amounts of butyl acrylate, dicumyl peroxide, antioxidant 1010, and lubricant liquid paraffin added are 0.6 wt%, 0.2 wt%, 0.2 wt%, and 0.4 wt% of the mass of medium-density polyethylene, respectively.

[0074] (2) Montmorillonite, tetrabutyl titanate and trimethyloctadecyl ammonium bromide were added to an ethanol-water mixture (mass ratio 1:1) at a mass ratio of 1:0.3:1. The pH was adjusted to 5 with dilute hydrochloric acid. The mixture was then mixed at 50°C and 2500 rpm / min for 5 h. The mixture was then washed, centrifuged, and the solid was collected and ground through an 800-mesh sieve to obtain the modified inorganic filler for later use.

[0075] (3) A vanadium carbide aqueous solution with a concentration of 5 g / L was filtered to obtain a filter cake, which was then freeze-dried to constant weight. The vanadium carbide filter cake, polyethylene-acrylate copolymer, and modified inorganic filler were added to a high-speed mixer at a mass ratio of 1:5.5:0.1, and antioxidant 1010 with a total mass of 0.2 wt% of the raw materials was added. The mixture was mixed at 2500 rpm / min for 20 min to obtain a mixture. The mixture was then used to prepare a multifunctional polyethylene film in a molding press at 180℃ and 5 MPa.

[0076]

Example 3

[0077] Multifunctional polyethylene film was prepared according to the following method:

[0078] (1) Linear low-density polyethylene, butyl methacrylate, diisopropyl peroxide, antioxidant 1010, and liquid paraffin lubricant were added to a high-speed mixer and mixed for 10 min at a stirring speed of 4500 rpm / min. Then, the mixture was added to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder were 140, 155, 165, 165, 170, 175, and 175 °C, respectively. The screw speed was 60 rpm / min. After extrusion, the material was traction, water-cooled granulation, and dried to obtain polyethylene-acrylate copolymer.

[0079] The amounts of butyl methacrylate, diisopropyl peroxide dicarbonate, antioxidant 1010, and liquid paraffin lubricant added are 0.3 wt%, 0.05 wt%, 0.15 wt%, and 0.6 wt% of the mass of linear low-density polyethylene, respectively.

[0080] (2) Mica flakes, tetra-n-propyl zirconate and dodecyl dimethyl ammonium bromide were added to an ethanol-water mixture (mass ratio 1:1) at a mass ratio of 1.5:0.5:1. The pH was adjusted to 2 by dilute hydrochloric acid. The mixture was then mixed at 30°C and 4500 rpm / min for 4 hours. The mixture was then washed, centrifuged, and the solid was collected and ground through an 800-mesh sieve to obtain the modified inorganic filler for later use.

[0081] (3) A 5 g / L molybdenum carbide aqueous solution was filtered to obtain a filter cake, which was then freeze-dried to constant weight. The molybdenum carbide filter cake, polyethylene-acrylate copolymer, and modified inorganic filler were added to a high-speed mixer at a mass ratio of 1:2.8:0.2, and antioxidant 1010 was added at 0.15 wt% of the total mass of the raw materials. The mixture was mixed at 4500 rpm / min for 10 min to obtain a mixture. The mixture was then used to prepare a multifunctional polyethylene film in a molding press at 180℃ and 5 MPa.

[0082]

Example 4

[0083] Multifunctional polyethylene film was prepared according to the following method:

[0084] (1) Low-density polyethylene, methyl methacrylate, dicumyl peroxide, antioxidant 1010, and lubricant liquid paraffin were added to a high-speed mixer and mixed for 15 minutes at a stirring speed of 3500 rpm / min. Then, the mixture was added to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder were 145, 160, 165, 165, 170, 180, and 180°C, respectively. The feeding screw speed was 35 rpm / min. After extrusion, the material was traction, water-cooled granulation, and dried to obtain polyethylene-acrylate copolymer.

[0085] The amounts of methyl methacrylate, dicumyl peroxide, antioxidant 1010, and lubricant liquid paraffin added are 0.7 wt%, 0.2 wt%, 0.3 wt%, and 0.3 wt% of the mass of low-density polyethylene, respectively.

[0086] (2) Carbon nanotubes, allyltrichlorosilane and dihexadecanyldimethylammonium bromide were added to an ethanol-water mixture (mass ratio 1:1) at a mass ratio of 2:0.6:1. The pH was adjusted to 4 with dilute hydrochloric acid. The mixture was then mixed at 60°C and 3500 rpm / min for 6 hours. The mixture was then washed, centrifuged, and the solid was collected and ground through an 800-mesh sieve to obtain the modified inorganic filler for later use.

[0087] (3) A 5 g / L titanium carbide aqueous solution was filtered to obtain a filter cake, which was then freeze-dried to constant weight. The titanium carbide filter cake, polyethylene-acrylate copolymer, and modified inorganic filler were added to a high-speed mixer at a mass ratio of 1:4.5:1, and antioxidant 1010 was added at 0.3 wt% of the total mass of the raw materials. The mixture was mixed at 3500 rpm / min for 30 min to obtain a mixture. The mixture was then used to prepare a multifunctional polyethylene membrane in a molding press at 180℃ and 5 MPa.

[0088]

Example 5

[0089] Multifunctional polyethylene film was prepared according to the following method:

[0090] (1) Medium-density polyethylene, hydroxyethyl acrylate, tert-butyl peroxide, antioxidant 1010, and lubricant liquid paraffin were added to a high-speed mixer and mixed for 15 minutes at a stirring speed of 3500 rpm / min. Then, the mixture was added to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder were 150, 180, 200, 205, 205, 215, and 215°C, respectively. The screw speed was 50 rpm / min. After extrusion, the material was traction, water-cooled granulation, and dried to obtain polyethylene-acrylate copolymer.

[0091] The amounts of hydroxyethyl acrylate, tert-butyl peroxide, antioxidant 1010, and lubricant liquid paraffin added are 0.8 wt%, 0.05 wt%, 0.1 wt%, and 0.5 wt% of the mass of medium-density polyethylene, respectively.

[0092] (2) Carbon nanotubes, isopropyl trititanate, and dioctadecyl dimethyl ammonium chloride were added to an ethanol-water mixture (mass ratio 1:1) at a mass ratio of 2.5:0.6:1. The pH was adjusted to 4 with dilute hydrochloric acid. The mixture was then mixed at 70°C and 3500 rpm / min for 5 h. The mixture was then washed, centrifuged, and the solid was collected and ground through an 800-mesh sieve to obtain the modified inorganic filler for later use.

[0093] (3) A 5 g / L titanium carbide aqueous solution was filtered to obtain a filter cake, which was then freeze-dried to constant weight. The titanium carbide filter cake, polyethylene-acrylate copolymer, and modified inorganic filler were added to a high-speed mixer at a mass ratio of 1:14:5, and antioxidant 1010 was added at 0.1 wt% of the total mass of the raw materials. The mixture was mixed at 3500 rpm / min for 30 min to obtain a mixture. The mixture was then used to prepare a multifunctional polyethylene film in a molding press at 180℃ and 5 MPa.

[0094]

Example 6

[0095] Multifunctional polyethylene film was prepared according to the following method:

[0096] (1) High-density polyethylene, butyl acrylate, diisopropyl peroxide, antioxidant 1010, and liquid paraffin lubricant were added to a high-speed mixer and mixed for 20 minutes at a stirring speed of 3000 rpm / min. Then, the mixture was added to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder were 150, 180, 200, 205, 205, 215, and 215°C, respectively. The screw speed was 40 rpm / min. After extrusion, the material was traction, water-cooled granulation, and dried to obtain polyethylene-acrylate copolymer.

[0097] The amounts of butyl acrylate, diisopropyl peroxide dicarbonate, antioxidant 1010, and lubricant liquid paraffin added are 0.3 wt%, 0.05 wt%, 0.1 wt%, and 0.5 wt% of the mass of high-density polyethylene, respectively.

[0098] (2) Mica flakes, triethoxyvinylsilane, and hexadecyltrimethylammonium bromide were added to an ethanol-water mixture (mass ratio 1:1) at a mass ratio of 2.5:0.5:1. The pH was adjusted to 3 by dilute hydrochloric acid. The mixture was then mixed at 30°C and 3500 rpm / min for 4 hours. The mixture was then washed, centrifuged, and the solid was collected and ground through an 800-mesh sieve to obtain the modified inorganic filler for later use.

[0099] (3) The niobium carbide aqueous solution with a concentration of 5 g / L was filtered to obtain a filter cake, and then freeze-dried to constant weight. The niobium carbide filter cake, polyethylene-acrylate copolymer, and modified inorganic filler were added to a high-speed mixer at a mass ratio of 1:18:1, and antioxidant 1010 with a total mass of 0.1 wt% of the raw materials was added. The mixture was mixed at 3500 rpm / min for 30 min to obtain a mixture. The mixture was then used to prepare a multifunctional polyethylene film in a molding press at 180℃ and 5 MPa.

[0100]

Example 7

[0101] Multifunctional polyethylene film was prepared according to the following method:

[0102] (1) Medium-density polyethylene, butyl methacrylate, benzoyl peroxide, antioxidant 1010 and lubricant liquid paraffin were added to a high-speed mixer and mixed for 20 minutes at a stirring speed of 3000 rpm / min. Then, the mixture was added to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder were 160, 180, 200, 205, 205, 220 and 220°C, respectively. The feeding screw speed was 45 rpm / min. After extrusion, the material was traction, water-cooled granulation and dried to obtain polyethylene-acrylate copolymer.

[0103] The amounts of butyl methacrylate, benzoyl peroxide, antioxidant 1010, and lubricant liquid paraffin added are 0.6 wt%, 0.25 wt%, 0.1 wt%, and 0.6 wt% of the mass of medium-density polyethylene, respectively.

[0104] (2) Montmorillonite, triethoxyvinylsilane and hexadecyltrimethylammonium bromide were added to an ethanol-water mixture (mass ratio 1:1) at a mass ratio of 1.6:0.6:1. The pH was adjusted to 3 with dilute hydrochloric acid. The mixture was then mixed at 65°C and 4000 rpm / min for 4 hours. The mixture was then washed, centrifuged, and the solid was collected and ground through an 800-mesh sieve to obtain the modified inorganic filler for later use.

[0105] (3) A vanadium carbide aqueous solution with a concentration of 5 g / L was filtered to obtain a filter cake, which was then freeze-dried to constant weight. The vanadium carbide filter cake, polyethylene-acrylate copolymer, and modified inorganic filler were added to a high-speed mixer at a mass ratio of 1:5:0.7, and antioxidant 1010 with a total mass of 0.1 wt% of the raw materials was added. The mixture was mixed at 3500 rpm / min for 30 min to obtain a mixture. The mixture was then used to prepare a multifunctional polyethylene film in a molding press at 180℃ and 5 MPa.

[0106] Comparative Example 1

[0107] The polyethylene film was prepared in essentially the same manner as in Example 1, except that the polyethylene-acrylate copolymer in step (3) was replaced with the same mass of unmodified high-density polyethylene.

[0108] Comparative Example 2

[0109] The polyethylene film was prepared in essentially the same manner as in Example 1, except that the modified inorganic filler in step (3) was replaced with the same mass of reduced graphene oxide.

[0110] Comparative Example 3

[0111] The polyethylene film was prepared in essentially the same manner as in Example 1, except that in step (2), triethoxyvinylsilane was not added when preparing the modified inorganic filler.

[0112] Comparative Example 4

[0113] The polyethylene film was prepared in essentially the same manner as in Example 1, except that in step (2), cetyltrimethylammonium bromide was not added when preparing the modified inorganic filler.

[0114] Comparative Example 5

[0115] The polyethylene film was prepared in basically the same way as in Example 1, except that in step (2), when preparing the modified inorganic filler, the mass ratio of reduced graphene oxide, triethoxyvinylsilane, and hexadecyltrimethylammonium bromide was modified to 1.5:1:1.5.

[0116] The gas barrier properties, mechanical properties, and electromagnetic shielding properties of the polyethylene films prepared in each embodiment and comparative example were tested, and the test results are shown in Table 1.

[0117] Table 1. Performance Test Results

[0118]

[0119]

[0120] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a multifunctional polyethylene film, characterized in that, Includes the following steps: 1) Under the action of a peroxide initiator and optional additives, polyethylene resin and acrylate are melt-reacted to prepare a polyethylene-acrylate copolymer; 2) Mix the inorganic filler, coupling agent, and long-chain quaternary ammonium salt in a dispersion medium, adjust the pH to 2-7, stir at high speed for 2-12 hours at a treatment temperature of 20-80℃, separate the solid, and obtain the modified filler. 3) The transition metal carbide is mixed at high speed with the polyethylene-acrylate copolymer obtained in step 1), the modified filler obtained in step 2), and optional additives, and then molded to obtain a multifunctional polyethylene film. In step 2), the mass ratio of the inorganic filler, coupling agent, and long-chain quaternary ammonium salt is (1-2.5):(0.3-0.7):1; In step 3), the mass ratio of transition metal carbide, polyethylene-acrylate copolymer, and modified filler is 1:(2-20):(0.1-5); The long-chain quaternary ammonium salt is selected from one or more of hexadecyltrimethylammonium bromide, trimethyloctadecylammonium bromide, dihexadecyldimethylammonium bromide, dioctadecyldimethylammonium chloride, and didodecyldimethylammonium bromide.

2. The method for preparing the multifunctional polyethylene film according to claim 1, characterized in that, In step 2), the inorganic filler, coupling agent, and long-chain quaternary ammonium salt are mixed in a dispersion medium, the pH is adjusted to 2-5, and the mixture is stirred at high speed for 5-10 hours at a treatment temperature of 30-75℃. The solid is then separated to obtain the modified filler.

3. The method for preparing the multifunctional polyethylene film according to claim 1, characterized in that, In step 1), the amount of acrylate used is 0.1 to 1 wt%, based on the mass of polyethylene resin.

4. The method for preparing the multifunctional polyethylene film according to claim 3, characterized in that, In step 1), the amount of acrylate used is 0.2 to 0.8 wt%, based on the mass of polyethylene resin.

5. The method for preparing the multifunctional polyethylene film according to claim 4, characterized in that, In step 1), the amount of acrylate used is 0.3 to 0.7 wt%, based on the mass of polyethylene resin.

6. The method for preparing the multifunctional polyethylene film according to claim 3, characterized in that, The acrylate is one or more of ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, methyl methacrylate, and butyl methacrylate.

7. The method for preparing the multifunctional polyethylene film according to claim 2, characterized in that, In step 1), the amount of the peroxide initiator is 0.01 to 0.5 wt%, based on the mass of the polyethylene resin.

8. The method for preparing the multifunctional polyethylene film according to claim 7, characterized in that, In step 1), the amount of the peroxide initiator is 0.03 to 0.3 wt%, based on the mass of the polyethylene resin.

9. The method for preparing the multifunctional polyethylene film according to claim 8, characterized in that, In step 1), the amount of the peroxide initiator is 0.05 to 0.2 wt%, based on the mass of the polyethylene resin.

10. The method for preparing the multifunctional polyethylene film according to claim 7, characterized in that, The peroxide initiator is selected from one or more of benzoyl peroxide, tert-butyl peroxide, dicumyl peroxide, diisopropyl peroxide, and ditert-butyl peroxide.

11. The method for preparing the multifunctional polyethylene film according to claim 1, characterized in that, The polyethylene resin is one or more of high-density polyethylene, medium-density polyethylene, and low-density polyethylene.

12. The method for preparing the multifunctional polyethylene film according to claim 11, characterized in that, The molecular weight of the polyethylene resin is 10 × 10⁻⁶. 4 ~80×10 4 g / mol.

13. The method for preparing the multifunctional polyethylene film according to claim 12, characterized in that, The molecular weight of the polyethylene resin is 40 × 10⁻⁶. 4 ~70×10 4 g / mol.

14. The method for preparing the multifunctional polyethylene film according to any one of claims 1 to 13, characterized in that, The reaction conditions in step 1) are: temperature 140℃~260℃, rotation speed 20~60rpm / min.

15. The method for preparing the multifunctional polyethylene film according to claim 14, characterized in that, The reaction conditions in step 1) are: temperature 160℃~230℃, rotation speed 30~40rpm / min.

16. The method for preparing the multifunctional polyethylene film according to any one of claims 1 to 13, characterized in that, The inorganic filler is non-metallic nanoparticles.

17. The method for preparing the multifunctional polyethylene film according to claim 16, characterized in that, The inorganic filler is one or more of the following: reduced graphene oxide, graphene oxide, montmorillonite, mica sheets, carbon nanotubes, silicon carbide nanoparticles, silicon micropowder, and silicon nanowires.

18. The method for preparing the multifunctional polyethylene film according to claim 16, characterized in that, The coupling agent is one or more of the following: silane coupling agent, titanate coupling agent, zirconate coupling agent, and aluminate coupling agent.

19. The method for preparing the multifunctional polyethylene film according to claim 18, characterized in that, The coupling agent is one or more of the following: triethoxyvinylsilane, γ-aminopropyltriethoxysilane, allyltrichlorosilane, tetrabutyl titanate, isopropyl titanate, and tetra-n-propylzirconate.

20. The method for preparing the multifunctional polyethylene film according to claim 1, characterized in that, In step 3), the mass ratio of transition metal carbide, polyethylene-acrylate copolymer, and modified filler is 1:(4-15):(0.1-1).

21. The method for preparing the multifunctional polyethylene film according to any one of claims 1 to 13, characterized in that, The additives are one or more of antioxidants, lubricants, plasticizers, and flame retardants.

22. The application of a multifunctional polyethylene film prepared by the method according to any one of claims 1 to 21 in the fields of energy storage, electronic communication, and food packaging.

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