A graphene-modified antistatic film and its preparation method

Abstract

The present invention relates to the technical field of antistatic films, and specifically relates to a graphene-modified antistatic film and a preparation method thereof, which comprise the following raw materials in parts by weight: 45-50 parts of polylactic acid, 12-14 parts of terminal maleimide polylactic acid, 6-8 parts of conductive composite resin, 3-5 parts of modified graphene, and 2-4 parts of antioxidant; by modifying graphene and adding a conductive composite resin, a crosslinked self-healing structure can be formed between it and the terminal maleimide polylactic acid resin, solving the problems of poor toughness and poor thermal stability of the polylactic acid film material. At the same time, due to the combined action of the conductive composite resin and the modified graphene, it also has good antistatic performance.

Description

Technical Field

[0001] The present invention relates to the technical field of antistatic films, and particularly relates to a graphene-modified antistatic film and a preparation method thereof. Background Art

[0002] With the development of the market, people are increasingly concerned about the "white pollution" problem of plastic packaging materials. Polylactic acid film materials are a kind of degradable thermoplastic materials, which have good biocompatibility, thermoplastic processability, good oil resistance and grease resistance. However, polylactic acid film materials also have problems of poor toughness and poor thermal stability. At the same time, due to some market demands, packaging materials are required to have good antistatic ability. Currently, conductive fillers or conductive polymers are usually selected to improve their antistatic ability. However, the addition of these materials will further highlight the problems of poor toughness and poor thermal stability of polylactic acid film materials, and they can no longer meet the market demands. Summary of the Invention

[0003] The purpose of the present invention is to provide a graphene-modified antistatic film and a preparation method thereof. By modifying graphene and adding a conductive composite resin, a cross-linked self-healing structure can be formed between it and the maleimide-terminated polylactic acid resin, solving the problems of poor toughness and poor thermal stability of polylactic acid film materials. At the same time, due to the combined action of the conductive composite resin and the modified graphene, it also has good antistatic performance.

[0004] The purpose of the present invention can be realized by the following technical solutions: A preparation method of a graphene-modified antistatic film is obtained through the following steps: Step S1: Weigh the following raw materials in parts by weight: 45-50 parts of polylactic acid, 12-14 parts of maleimide-terminated polylactic acid, 6-8 parts of conductive composite resin, 3-5 parts of modified graphene, and 2-4 parts of antioxidant;

[0005] Step S2: Mix the polylactic acid, maleimide-terminated polylactic acid, conductive composite resin, modified graphene, and antioxidant, and send them into a twin-screw extruder. Under the conditions of a temperature of 160-170 °C, a pressure of 2-2.2 MPa, and a rotation speed of 200-240 rpm, melt and plasticize, extrude and press into sheets, and then under the conditions of a temperature of 140-160 °C and a stretching speed of 100 m / min, stretch, wind up, and cut to obtain a graphene-modified antistatic film;

[0006] The polylactic acid is Hongfuyuan Plasticizing PLA 4032D;

[0007] The maleimide-terminated polylactic acid is Xingbei Aike Biology PLA-Mal;

[0008] The antioxidant is Adiko HP-10;

[0009] The modified graphene is prepared by the following steps:

[0010] Step A1: Mix expanded graphite, N,N-dimethylformamide and deionized water and ultrasonically disperse for 1 - 1.5 h. Then add titanium chloride solution and hydrochloric acid solution. Under the conditions of a stirring rate of 400 - 500 rpm and a temperature of 85 - 90 °C, react for 3 - 4 h. Then add nitric acid solution and continue to react for 3 - 4 h to obtain precursor 1. Mix aluminum chloride, zinc chloride and ethanol, stir and add acetylacetone under the conditions of a stirring rate of 160 - 180 rpm and room temperature, stir and react for 3 - 4 h. Then add precursor 1 and deionized water, ultrasonically disperse for 40 - 60 min. Under the condition of a temperature of 85 - 90 °C, react for 4 - 5 h, centrifuge, filter, dry, transfer it to a muffle furnace, and calcine at a temperature of 450 °C for 2 - 2.5 h to obtain precursor 2;

[0011] The molar concentration of the titanium chloride solution is 0.1 mol / L, the mass fraction of the hydrochloric acid solution is 35%, the mass fraction of the nitric acid solution is 10%, and the dosage ratio of expanded graphite, titanium chloride solution, hydrochloric acid solution and nitric acid solution is 2 - 2.4 g : 38 - 40 mL : 180 - 200 mL : 15 - 18 mL; the dosage ratio of aluminum chloride, zinc chloride, ethanol, acetylacetone, precursor 1 and deionized water is 0.007 - 0.0075 g : 0.18 - 0.19 g : 25 - 30 mL : 0.0032 - 0.0035 mol : 3 - 3.2 g : 35 - 40 mL;

[0012] The expanded graphite is Jinqianrun 325-mesh expanded graphite;

[0013] During the reaction process, under the action of ultrasound, the expanded graphite is mechanically exfoliated to form a multi-layer graphene structure. At the same time, due to the addition of hydrochloric acid solution and nitric acid solution, the positively charged titanium ions are attracted by the multi-layer graphene structure through electrostatic interaction after exfoliation, so that titanium oxide is deposited on the surface of the multi-layer graphene structure to obtain precursor 1. Then, using acetylacetone as a chelating agent, it chelates with aluminum ions and zinc ions to form a chelate. Through the adsorption between the chelate and precursor 1, the chelate is adsorbed on precursor 1. After calcination, a special structure of zinc oxide-doped alumina powder is formed on the surface of precursor 1 to obtain precursor 2;

[0014] Step A2: Mix 4-maleimidylbenzoic acid, γ-glycidoxypropyltrimethoxysilane and toluene, react for 4 - 6 h under nitrogen protection, a stirring rate of 180 - 200 rpm and a temperature of 60 °C to obtain a modified silane. Mix precursor 2, the modified silane, ethanol and deionized water and ultrasonically disperse. Under the conditions of a stirring rate of 180 - 200 rpm and a temperature of 80 °C, stir and add glacial acetic acid, and react for 6 - 8 h to obtain the modified graphene;

[0015] The molar ratio of 4-maleimidobenzoic acid to γ-glycidoxypropyltrimethoxysilane is 0.01 - 0.012 mol: 0.012 mol; the mass ratio of precursor 2, modified silane, ethanol, deionized water and glacial acetic acid is 1.4 - 1.6 g: 0.3 - 0.36 g: 15 - 20 mL: 5 - 8 mL: 0.08 - 0.1 mL;

[0016] During the reaction process, the carboxyl group in 4-maleimidobenzoic acid reacts with the epoxy group in γ-glycidoxypropyltrimethoxysilane to obtain the modified silane. Then, in ethanol and deionized water, the modified silane undergoes hydrolysis and combines with precursor 2 to obtain modified graphene;

[0017] The conductive composite resin is prepared through the following steps:

[0018] Step B1: Mix epichlorohydrin and tetrabutylammonium hydrogensulfate, stir and add furfuryl alcohol at a stirring rate of 240 - 280 rpm and at room temperature, react for 4 - 6 h, then add sodium hydroxide solution and continue to react for 2 - 3 h to obtain intermediate a. Mix intermediate a, furfurylamine and toluene, and react at a stirring rate of 180 - 220 rpm and at a temperature of 110 - 115 °C for 3 - 4 h to obtain intermediate b;

[0019] The mass fraction of the sodium hydroxide solution is 50%, and the molar ratio of epichlorohydrin, tetrabutylammonium hydrogensulfate, furfuryl alcohol, and sodium hydroxide solution is 1.1 - 1.12 mol: 3.5 - 3.8 g: 1 - 1.04 mol: 140 - 150 mL; the molar ratio of intermediate a to furfurylamine is 0.18 - 0.19 mol: 0.09 - 0.095 mol;

[0020] During the reaction process, under the action of tetrabutylammonium hydrogensulfate, the epoxy group in epichlorohydrin reacts with the hydroxyl group in furfuryl alcohol to form an ether bond and generate a hydroxyl group. Then, under the action of the sodium hydroxide solution, the newly generated hydroxyl group reacts with chlorine to form an epoxy group to obtain intermediate a. The epoxy group in intermediate a then reacts with the amino group in furfurylamine and generates a hydroxyl group to obtain intermediate b;

[0021]

[0022] Step B2: Mix polyethylene glycol, intermediate b and N,N-dimethylformamide, stir and add isophorone diisocyanate at a stirring rate of 160 - 180 rpm and at a temperature of 65 - 70 °C, react for 3 - 4 h, then add 2,4-diaminobenzenesulfonic acid sodium salt and raise the temperature to 80 - 85 °C, continue to react for 4 - 5 h, cool to room temperature and add deionized water, and continue to stir for 30 - 40 min to obtain a polyurethane prepolymer system;

[0023] The dosage ratio of polyethylene glycol, intermediate b, isophorone diisocyanate, sodium 2,4-diaminobenzenesulfonate and deionized water is 18 - 20 g : 0.01 mol : 0.045 - 0.048 mol : 0.01 mol : 120 - 150 mL;

[0024] The polyethylene glycol is MCE PEG2000;

[0025] During the reaction process, the hydroxyl groups in polyethylene glycol and intermediate b react with the isocyanate groups in isophorone diisocyanate to form a urethane structure. Then, sodium 2,4-diaminobenzenesulfonate is added to continue the reaction to form a urea structure. Finally, deionized water is added to obtain a polyurethane prepolymer system.

[0026] Step B3: Mix pyrrole and the polyurethane prepolymer system, stir and add a hydrochloric acid solution at a stirring rate of 150 - 180 rpm and at room temperature to adjust the pH value to 1.5. Then cool down to 0 - 5 °C and add a ferric chloride solution, and continue the reaction for 2.5 - 3 h to obtain a conductive composite resin.

[0027] The mass fraction of the hydrochloric acid solution is 5%, and the ferric chloride solution is 10%. The dosage ratio of pyrrole, the polyurethane prepolymer system and the ferric chloride solution is 0.042 - 0.044 mol : 90 - 100 mL : 110 - 120 mL;

[0028] During the reaction process, through the method of in-situ chemical oxidative polymerization, under the action of the ferric chloride solution, pyrrole polymerizes in the polyurethane prepolymer system to form polypyrrole segments, and covalently and non-covalently combines with the polyurethane prepolymer to obtain a conductive composite resin.

[0029] Advantages of the present invention: The present invention discloses a graphene-modified antistatic film and a preparation method thereof. By modifying graphene and adding a conductive composite resin, a crosslinked self-healing structure can be formed between it and the maleimide-terminated polylactic acid resin, solving the problems of poor toughness and poor thermal stability of polylactic acid film materials. At the same time, due to the combined action of the conductive composite resin and the modified graphene, it also has good antistatic performance; during the melt blending process, due to the large number of branched furan groups in the conductive composite resin, it undergoes a Diels-Alder reaction with the modified graphene and the maleimide groups in the maleimide-terminated polylactic acid to form a crosslinked self-healing DA structure, thus effectively improving the toughness and thermal stability of the antistatic film. By modifying graphene, graphene is combined with titanium oxide, and then a special structure of zinc oxide-doped alumina powder is formed on the surface, making the modified graphene have good electrical conductivity. And it is combined with a conductive composite resin containing polypyrrole segments, thus improving the antistatic performance of the film. At the same time, due to the presence of its maleimide structure, it can effectively combine with the modified silane, thus avoiding its agglomeration in the matrix resin. And due to the covalent connection between the modified graphene and the matrix resin, it can play a stress node role when the film is subjected to external forces, and also improves the mechanical properties of the antistatic film to a certain extent. Detailed implementation manners

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0031] Example 1 A preparation method of a graphene-modified antistatic film is obtained through the following steps: Step S1: Weigh the following raw materials in parts by weight: 45 parts of polylactic acid, 12 parts of maleimide-terminated polylactic acid, 6 parts of conductive composite resin, 5 parts of modified graphene, and 2 parts of antioxidant;

[0032] Step S2: Mix the polylactic acid, maleimide-terminated polylactic acid, conductive composite resin, modified graphene, and antioxidant, and feed them into a twin-screw extruder. Under the conditions of a temperature of 160 °C, a pressure of 2 MPa, and a rotation speed of 200 rpm, melt plasticize, extrude and pelletize, and then under the conditions of a temperature of 140 °C and a stretching speed of 100 m / min, stretch, wind up, and cut to obtain a graphene-modified antistatic film;

[0033] The polylactic acid is Hongfuyuan Plasticization PLA 4032D;

[0034] The terminal maleimide polylactic acid is Xingbei Aike Biology's PLA-Mal;

[0035] The antioxidant is ADEKA HP-10;

[0036] The modified graphene is prepared through the following steps:

[0037] Step A1: Mix expanded graphite, N,N-dimethylformamide, and deionized water and ultrasonically disperse for 1 h. Then add titanium chloride solution and hydrochloric acid solution. React at a stirring rate of 400 rpm and a temperature of 85 °C for 3 h. Then add nitric acid solution and continue to react for 3 h to obtain precursor 1. Mix aluminum chloride, zinc chloride, and ethanol, stir and add acetylacetone at a stirring rate of 160 rpm at room temperature, and stir and react for 3 h. Then add precursor 1 and deionized water, ultrasonically disperse for 40 min, react at a temperature of 85 °C for 4 h, centrifuge, filter, dry, transfer it to a muffle furnace, and calcine at a temperature of 450 °C for 2 h to obtain precursor 2;

[0038] The molar concentration of the titanium chloride solution is 0.1 mol / L, the mass fraction of the hydrochloric acid solution is 35%, the mass fraction of the nitric acid solution is 10%, and the dosage ratio of expanded graphite, titanium chloride solution, hydrochloric acid solution, and nitric acid solution is 2 g: 38 mL: 180 mL: 15 mL; the dosage ratio of aluminum chloride, zinc chloride, ethanol, acetylacetone, precursor 1, and deionized water is 0.007 g: 0.18 g: 25 mL: 0.0032 mol: 3 g: 35 mL;

[0039] The expanded graphite is Jinqianrun 325-mesh expanded graphite;

[0040] Step A2: Mix 4-maleimidobenzoic acid, γ-glycidyletheroxypropyltrimethoxysilane, and toluene, react under nitrogen protection at a stirring rate of 180 rpm and a temperature of 60 °C for 4 h to obtain modified silane. Mix precursor 2, modified silane, ethanol, and deionized water and ultrasonically disperse, stir and add glacial acetic acid at a stirring rate of 180 rpm and a temperature of 80 °C, and react for 6 h to obtain modified graphene;

[0041] The dosage ratio of 4-maleimidobenzoic acid and γ-glycidyletheroxypropyltrimethoxysilane is 0.01 mol: 0.012 mol; the dosage ratio of precursor 2, modified silane, ethanol, deionized water, and glacial acetic acid is 1.4 g: 0.3 g: 15 mL: 5 mL: 0.08 mL;

[0042] The conductive composite resin is prepared through the following steps:

[0043] Step B1: Mix epichlorohydrin and tetrabutylammonium hydrogen sulfate, stir and add furfuryl alcohol at a stirring rate of 240 rpm and at room temperature, react for 6 h, then add sodium hydroxide solution and continue to react for 3 h to obtain intermediate a. Mix intermediate a, furfurylamine and toluene, and react at a stirring rate of 220 rpm and at a temperature of 110 °C for 3 h to obtain intermediate b;

[0044] The mass fraction of the sodium hydroxide solution is 50%, and the dosage ratio of epichlorohydrin, tetrabutylammonium hydrogen sulfate, furfuryl alcohol, and sodium hydroxide solution is 1.12 mol: 3.5 g: 1 mol: 150 mL; the dosage ratio of intermediate a and furfurylamine is 0.19 mol: 0.09 mol;

[0045] Step B2: Mix polyethylene glycol, intermediate b and N, N-dimethylformamide, stir and add isophorone diisocyanate at a stirring rate of 180 rpm and at a temperature of 65 °C, react for 3 h, then add sodium 2,4-diaminobenzenesulfonate and raise the temperature to 85 °C, continue to react for 4 h, cool to room temperature and add deionized water, and continue to stir for 40 min to obtain a polyurethane prepolymer system;

[0046] The dosage ratio of polyethylene glycol, intermediate b, isophorone diisocyanate, sodium 2,4-diaminobenzenesulfonate and deionized water is 18 g: 0.01 mol: 0.048 mol: 0.01 mol: 120 mL;

[0047] The polyethylene glycol is MCE PEG2000;

[0048] Step B3: Mix pyrrole and the polyurethane prepolymer system, stir and add hydrochloric acid solution at a stirring rate of 150 rpm and at room temperature, adjust the pH value to 1.5, then cool to 0 °C and add ferric chloride solution, and continue to react for 3 h to obtain a conductive composite resin;

[0049] The mass fraction of the hydrochloric acid solution is 5%, the ferric chloride solution is 10%, and the dosage ratio of pyrrole, the polyurethane prepolymer system and the ferric chloride solution is 0.044 mol: 90 mL: 120 mL.

[0050] Example 2 A preparation method of a graphene-modified antistatic film is obtained through the following steps: Step S1: Weigh the following raw materials in parts by weight: 45 parts of polylactic acid, 14 parts of terminal maleimide polylactic acid, 8 parts of conductive composite resin, 3 parts of modified graphene and 2 parts of antioxidant;

[0051] Step S2: Mix polylactic acid, maleimide-terminated polylactic acid, conductive composite resin, modified graphene, and antioxidant, and feed them into a twin-screw extruder. Under the conditions of a temperature of 160°C, a pressure of 2.2 MPa, and a rotation speed of 200 rpm, melt and plasticize, extrude and press into sheets, then under the conditions of a temperature of 160°C and a stretching speed of 100 m / min, stretch, wind up, and cut to obtain a graphene-modified antistatic film;

[0052] The polylactic acid is Hongfuyuan Plasticizing PLA 4032D;

[0053] The maleimide-terminated polylactic acid is Xingbei Aike Biology PLA-Mal;

[0054] The antioxidant is ADEKA HP-10;

[0055] The modified graphene is prepared through the following steps:

[0056] Step A1: Mix expanded graphite, N,N-dimethylformamide, and deionized water and ultrasonically disperse for 1.5 h, then add titanium chloride solution and hydrochloric acid solution. Under the conditions of a stirring rate of 400 rpm and a temperature of 90°C, react for 3 h, then add nitric acid solution and continue to react for 3 h to obtain precursor 1. Mix aluminum chloride, zinc chloride, and ethanol, under the conditions of a stirring rate of 180 rpm and room temperature, stir and add acetylacetone, stir and react for 3 - 4 h, then add precursor 1 and deionized water, ultrasonically disperse for 40 min, under the condition of a temperature of 90°C, react for 4 h, centrifuge, filter, dry, transfer it to a muffle furnace, and calcine at a temperature of 450°C for 2.5 h to obtain precursor 2;

[0057] The molar concentration of the titanium chloride solution is 0.1 mol / L, the mass fraction of the hydrochloric acid solution is 35%, the mass fraction of the nitric acid solution is 10%, and the dosage ratio of expanded graphite, titanium chloride solution, hydrochloric acid solution, and nitric acid solution is 2.4 g: 38 mL: 200 mL: 15 mL; the dosage ratio of aluminum chloride, zinc chloride, ethanol, acetylacetone, precursor 1, and deionized water is 0.0075 g: 0.18 g: 25 mL: 0.0035 mol: 3.2 g: 35 mL;

[0058] The expanded graphite is Jinqianrun 325-mesh expanded graphite;

[0059] Step A2: Mix 4-maleimidobenzoic acid, γ-glycidoxypropyltrimethoxysilane, and toluene. Under nitrogen protection, under the conditions of a stirring rate of 180 rpm and a temperature of 60°C, react for 6 h to obtain a modified silane. Mix precursor 2, modified silane, ethanol, and deionized water and ultrasonically disperse. Under the conditions of a stirring rate of 200 rpm and a temperature of 80°C, stir and add glacial acetic acid, and react for 6 h to obtain modified graphene;

[0060] The dosage ratio of 4-maleimidobenzoic acid to γ-glycidoxypropyltrimethoxysilane is 0.012 mol: 0.012 mol; the dosage ratio of precursor 2, modified silane, ethanol, deionized water and glacial acetic acid is 1.4 g: 0.36 g: 15 mL: 5 mL: 0.1 mL;

[0061] The conductive composite resin is prepared by the following steps:

[0062] Step B1: Mix epichlorohydrin and tetrabutylammonium hydrogen sulfate, stir and add furfuryl alcohol at a stirring rate of 240 rpm and at room temperature, react for 4 h, then add sodium hydroxide solution and continue to react for 2 h to obtain intermediate a. Mix intermediate a, furfurylamine and toluene, and react at a stirring rate of 180 rpm and at 110 °C for 3 h to obtain intermediate b;

[0063] The mass fraction of the sodium hydroxide solution is 50%, and the dosage ratio of epichlorohydrin, tetrabutylammonium hydrogen sulfate, furfuryl alcohol, and sodium hydroxide solution is 1.1 mol: 3.5 g: 1 mol: 140 mL; the dosage ratio of intermediate a to furfurylamine is 0.18 mol: 0.09 mol;

[0064] Step B2: Mix polyethylene glycol, intermediate b and N,N-dimethylformamide, stir and add isophorone diisocyanate at a stirring rate of 160 rpm and at 65 °C, react for 3 h, then add 2,4-diaminobenzenesulfonic acid sodium salt and raise the temperature to 80 °C, continue to react for 4 h, cool to room temperature and add deionized water, and continue to stir for 30 min to obtain a polyurethane prepolymer system;

[0065] The dosage ratio of polyethylene glycol, intermediate b, isophorone diisocyanate, 2,4-diaminobenzenesulfonic acid sodium salt and deionized water is 18 g: 0.01 mol: 0.045 mol: 0.01 mol: 120 mL;

[0066] The polyethylene glycol is MCE PEG2000;

[0067] Step B3: Mix pyrrole and the polyurethane prepolymer system, stir and add hydrochloric acid solution at a stirring rate of 150 rpm and at room temperature to adjust the pH value to 1.5, then cool to 0 °C and add ferric chloride solution, and continue to react for 2.5 h to obtain the conductive composite resin;

[0068] The mass fraction of the hydrochloric acid solution is 5%, the ferric chloride solution is 10%, and the dosage ratio of pyrrole, the polyurethane prepolymer system and the ferric chloride solution is 0.042 mol: 90 mL: 110 mL.

[0069] Example 3 A preparation method of a graphene-modified antistatic film, which is prepared by the following steps: Step S1: Weigh the following raw materials in parts by weight: 50 parts of polylactic acid, 14 parts of terminal maleimide polylactic acid, 8 parts of conductive composite resin, 5 parts of modified graphene, and 4 parts of antioxidant;

[0070] Step S2: Mix polylactic acid, terminal maleimide polylactic acid, conductive composite resin, modified graphene, and antioxidant, and feed them into a twin-screw extruder. Under the conditions of a temperature of 170 °C, a pressure of 2.2 MPa, and a rotation speed of 240 rpm, melt and plasticize, extrude and press into sheets, and then under the conditions of a temperature of 160 °C and a stretching speed of 100 m / min, stretch, wind up, and cut to obtain a graphene-modified antistatic film;

[0071] The polylactic acid is Hongfuyuan Plasticizing PLA 4032D;

[0072] The terminal maleimide polylactic acid is Xingbei Aike Biology PLA-Mal;

[0073] The antioxidant is Adiko HP-10;

[0074] The modified graphene is prepared by the following steps:

[0075] Step A1: Mix expanded graphite, N,N-dimethylformamide, and deionized water and ultrasonically disperse for 1.5 h, then add titanium chloride solution and hydrochloric acid solution. Under the conditions of a stirring rate of 500 rpm and a temperature of 90 °C, react for 4 h, then add nitric acid solution and continue to react for 4 h to obtain precursor 1. Mix aluminum chloride, zinc chloride, and ethanol, and under the conditions of a stirring rate of 180 rpm and room temperature, stir and add acetylacetone, stir and react for 4 h, then add precursor 1 and deionized water, ultrasonically disperse for 60 min, and under the conditions of a temperature of 90 °C, react for 5 h, centrifuge, filter, dry, transfer it to a muffle furnace, and calcine at a temperature of 450 °C for 2.5 h to obtain precursor 2;

[0076] The molar concentration of the titanium chloride solution is 0.1 mol / L, the mass fraction of the hydrochloric acid solution is 35%, the mass fraction of the nitric acid solution is 10%, and the dosage ratio of expanded graphite, titanium chloride solution, hydrochloric acid solution, and nitric acid solution is 2.4 g: 40 mL: 200 mL: 18 mL; the dosage ratio of aluminum chloride, zinc chloride, ethanol, acetylacetone, precursor 1, and deionized water is 0.0075 g: 0.19 g: 30 mL: 0.0035 mol: 3.2 g: 40 mL;

[0077] The expanded graphite is Jinqianrun 325-mesh expanded graphite;

[0078] Step A2: Mix 4-maleimidobenzoic acid, γ-glycidoxypropyltrimethoxysilane, and toluene. Under nitrogen protection, with a stirring rate of 200 rpm and a temperature of 60 °C, react for 6 h to obtain a modified silane. Mix precursor 2, the modified silane, ethanol, and deionized water and ultrasonically disperse them. Under a stirring rate of 200 rpm and a temperature of 80 °C, stir and add glacial acetic acid, and react for 8 h to obtain modified graphene;

[0079] The dosage ratio of 4-maleimidobenzoic acid to γ-glycidoxypropyltrimethoxysilane is 0.012 mol:0.012 mol; the dosage ratio of precursor 2, the modified silane, ethanol, deionized water, and glacial acetic acid is 1.6 g:0.36 g:20 mL:8 mL:0.1 mL;

[0080] The conductive composite resin is prepared through the following steps:

[0081] Step B1: Mix epichlorohydrin and tetrabutylammonium hydrogensulfate. Under a stirring rate of 280 rpm and at room temperature, stir and add furfuryl alcohol, and react for 6 h. Then add a sodium hydroxide solution and continue to react for 3 h to obtain intermediate a. Mix intermediate a, furfurylamine, and toluene. Under a stirring rate of 220 rpm and a temperature of 115 °C, react for 4 h to obtain intermediate b;

[0082] The mass fraction of the sodium hydroxide solution is 50%, and the dosage ratio of epichlorohydrin, tetrabutylammonium hydrogensulfate, furfuryl alcohol, and the sodium hydroxide solution is 1.12 mol:3.8 g:1.04 mol:150 mL; the dosage ratio of intermediate a to furfurylamine is 0.19 mol:0.095 mol;

[0083] Step B2: Mix polyethylene glycol, intermediate b, and N,N-dimethylformamide. Under a stirring rate of 180 rpm and a temperature of 70 °C, stir and add isophorone diisocyanate, and react for 4 h. Then add 2,4-diaminobenzenesulfonic acid sodium salt and raise the temperature to 85 °C, and continue to react for 5 h. Cool to room temperature and add deionized water, and continue to stir for 40 min to obtain a polyurethane prepolymer system;

[0084] The dosage ratio of polyethylene glycol, intermediate b, isophorone diisocyanate, 2,4-diaminobenzenesulfonic acid sodium salt, and deionized water is 20 g:0.01 mol:0.048 mol:0.01 mol:150 mL;

[0085] The polyethylene glycol is MCE PEG2000;

[0086] Step B3: Mix pyrrole and the polyurethane prepolymer system, stir and add hydrochloric acid solution under the conditions of a stirring rate of 180 rpm and a temperature of room temperature, adjust the pH value to 1.5, then cool down to 5 °C and add ferric chloride solution, and continue the reaction for 3 h to obtain a conductive composite resin;

[0087] The mass fraction of the hydrochloric acid solution is 5%, the ferric chloride solution is 10%, and the dosage ratio of pyrrole, the polyurethane prepolymer system and the ferric chloride solution is 0.044 mol: 100 mL: 120 mL.

[0088] Comparative Example 1 Compared with Example 3, in the preparation process of the graphene-modified antistatic film in Example 3, the modified graphene was replaced with Kolude TG1000 graphene, and other steps were the same.

[0089] Comparative Example 2 Compared with Example 3, pyrrole was removed in the preparation process of the conductive composite resin in Example 3, and other steps were the same.

[0090] Take the graphene-modified antistatic films prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2, use a tensile testing machine to test their tear strength, the sample size is 50 mm × 10 mm, the tear rate is 150 mm / min, use a support type impact testing machine to test their impact strength to judge their mechanical properties, the sample size is 50 mm × 10 mm, refer to IEC61340-2-3, use a heavy hammer type surface impedance tester to test their surface resistance to judge their antistatic properties, bend the sample 100 times repeatedly, and age it in an ultraviolet aging box for 3 d, then test its conductivity and calculate its performance retention rate to judge the retention of antistatic performance after long-term use. The test results are shown in Table 1 below: Test Results Table

[0091] Test Items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Tear Strength (kN / m) 156.9 156.5 157.8 149.9 155.3 <![CDATA[Impact strength (kJ / m 2 )]]> 17.42 17.31 17.89 16.34 17.52 <![CDATA[Surface resistance (×10 8 Ω / sq)]]> 0.882 0.879 0.875 1.024 0.987 Performance Retention Rate (%) 93.41 93.59 93.70 85.31 89.72

[0092] It can be seen from the test results in the shown table that by comparing Example 1, Example 2 and Example 3 with Comparative Example 1 and Comparative Example 2, in Comparative Example 1, in the preparation process of the graphene-modified antistatic film in Example 3, the modified graphene was replaced with Kolude TG1000 graphene. Due to the lack of modification of graphene, it was unable to form a crosslinked self-healing structure, and the special structure formed by its doping with zinc oxide and alumina powder was lacking, resulting in a significant decrease in its mechanical properties, antistatic properties and antistatic properties after long-term use. In Comparative Example 2, pyrrole was removed in the preparation process of the conductive composite resin in Example 3. Due to the lack of polypyrrole segments, the conductivity of the conductive composite resin itself decreased, resulting in a decrease in its antistatic properties and antistatic properties after long-term use.

[0093] In the description of the specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0094] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A preparation method of a graphene-modified antistatic film, characterized in that: It is prepared through the following steps: Step S1: Weigh the following raw materials in parts by weight: 45-50 parts of polylactic acid, 12-14 parts of terminal maleimide polylactic acid, 6-8 parts of conductive composite resin, 3-5 parts of modified graphene, and 2-4 parts of antioxidant; Step S2: Mix polylactic acid, terminal maleimide polylactic acid, conductive composite resin, modified graphene, and antioxidant, and feed them into a twin-screw extruder. Under the conditions of a temperature of 160-170 °C, a pressure of 2-2.2 MPa, and a rotation speed of 200-240 rpm, melt and plasticize, extrude and press into sheets, and then under the conditions of a temperature of 140-160 °C and a stretching speed of 100 m / min, stretch, wind up, and cut to obtain a graphene-modified antistatic film; The modified graphene is prepared through the following steps: Step A1: Mix expanded graphite, N,N-dimethylformamide, and deionized water and ultrasonically disperse for 1-1.5 h, then add titanium chloride solution and hydrochloric acid solution. Under the conditions of a stirring rate of 400-500 rpm and a temperature of 85-90 °C, react for 3-4 h, then add nitric acid solution and continue to react for 3-4 h to obtain precursor 1. Mix aluminum chloride, zinc chloride, and ethanol, and under the conditions of a stirring rate of 160-180 rpm and room temperature, stir and add acetylacetone, stir and react for 3-4 h, then add precursor 1 and deionized water, ultrasonically disperse for 40-60 min, and under the conditions of a temperature of 85-90 °C, react for 4-5 h, centrifuge, filter, dry, transfer it to a muffle furnace, and calcine at a temperature of 450 °C for 2-2.5 h to obtain precursor 2; In Step A1: The molar concentration of the titanium chloride solution is 0.1 mol / L, the mass fraction of the hydrochloric acid solution is 35%, the mass fraction of the nitric acid solution is 10%, and the dosage ratio of expanded graphite, titanium chloride solution, hydrochloric acid solution, and nitric acid solution is 2-2.4 g: 38-40 mL: 180-200 mL: 15-18 mL; the dosage ratio of aluminum chloride, zinc chloride, ethanol, acetylacetone, precursor 1, and deionized water is 0.007-0.0075 g: 0.18-0.19 g: 25-30 mL: 0.0032-0.0035 mol: 3-3.2 g: 35-40 mL; Step A2: Mix 4-maleimidylbenzoic acid, γ-glycidyletheroxypropyltrimethoxysilane, and toluene, and under the protection of nitrogen and a stirring rate of 180-200 rpm and a temperature of 60 °C, react for 4-6 h to obtain a modified silane. Mix precursor 2, modified silane, ethanol, and deionized water and ultrasonically disperse, and under the conditions of a stirring rate of 180-200 rpm and a temperature of 80 °C, stir and add glacial acetic acid and react for 6-8 h to obtain modified graphene; In step A2, the dosage ratio of 4-maleimidobenzoic acid to γ-glycidoxypropyltrimethoxysilane is 0.01 - 0.012 mol : 0.012 mol; the dosage ratio of precursor 2, modified silane, ethanol, deionized water, and glacial acetic acid is 1.4 - 1.6 g : 0.3 - 0.36 g : 15 - 20 mL : 5 - 8 mL : 0.08 - 0.1 mL; The conductive composite resin is prepared through the following steps: Step B1: Mix epichlorohydrin and tetrabutylammonium hydrogensulfate, stir and add furfuryl alcohol at a stirring rate of 240 - 280 rpm and at room temperature, react for 4 - 6 h, then add sodium hydroxide solution and continue to react for 2 - 3 h to obtain intermediate a. Mix intermediate a, furfurylamine, and toluene, and react at a stirring rate of 180 - 220 rpm and at a temperature of 110 - 115 °C for 3 - 4 h to obtain intermediate b; In step B1: The mass fraction of the sodium hydroxide solution is 50%, and the dosage ratio of epichlorohydrin, tetrabutylammonium hydrogensulfate, furfuryl alcohol, and sodium hydroxide solution is 1.1 - 1.12 mol : 3.5 - 3.8 g : 1 - 1.04 mol : 140 - 150 mL; the dosage ratio of intermediate a to furfurylamine is 0.18 - 0.19 mol : 0.09 - 0.095 mol; Step B2: Mix polyethylene glycol, intermediate b, and N,N-dimethylformamide, stir and add isophorone diisocyanate at a stirring rate of 160 - 180 rpm and at a temperature of 65 - 70 °C, react for 3 - 4 h, then add 2,4-diaminobenzenesulfonic acid sodium salt and raise the temperature to 80 - 85 °C, continue to react for 4 - 5 h, cool down to room temperature and add deionized water, and continue to stir for 30 - 40 min to obtain a polyurethane prepolymer system; In step B2: The dosage ratio of polyethylene glycol, intermediate b, isophorone diisocyanate, 2,4-diaminobenzenesulfonic acid sodium salt, and deionized water is 18 - 20 g : 0.01 mol : 0.045 - 0.048 mol : 0.01 mol : 120 - 150 mL; Step B3: Mix pyrrole and the polyurethane prepolymer system, stir and add hydrochloric acid solution at a stirring rate of 150 - 180 rpm and at room temperature, adjust the pH value to 1.5, then cool down to 0 - 5 °C and add ferric chloride solution, and continue to react for 2.5 - 3 h to obtain the conductive composite resin; In step B3: The mass fraction of the hydrochloric acid solution is 5%, the ferric chloride solution is 10%, and the dosage ratio of pyrrole, the polyurethane prepolymer system, and ferric chloride solution is 0.042 - 0.044 mol : 90 - 100 mL : 110 - 120 mL.

2. A graphene-modified antistatic film, characterized in that: Prepared according to any one of the preparation methods described in claim 1.

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