Preparation method of long-acting electromagnetic shielding solid wood board

Abstract

The application discloses a preparation method of long-acting electromagnetic shielding solid wood board and belongs to the technical field of wood functional treatment. The preparation method comprises the following steps: first, vacuum pressure impregnation treatment of the solid wood board is carried out by using a phenyl trimethoxysilane solution; then, impregnation treatment of the solid wood board is carried out by using an aniline solution and an ammonium persulfate solution respectively; then, electrochemical treatment of the solid wood board is carried out by using the aniline solution; and finally, spraying treatment of the solid wood board is carried out by using a water-based polyurethane coating. The electromagnetic shielding solid wood board prepared by the application has high electromagnetic shielding efficiency and excellent electromagnetic shielding efficiency stability, can effectively prevent the systems such as precision instruments, scientific measurement and medical care from being interfered by external electromagnetic waves, and has high economic value and social benefits.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wood functionalization treatment, and particularly relates to a preparation method of long-acting electromagnetic shielding solid wood board. BACKGROUND

[0002] At present, electronic instruments are increasingly developing towards miniaturization, integration, lightness and digitization, leading to problems such as misoperation, image obstruction, sound obstruction and the like caused by interference of external electromagnetic waves. Meanwhile, electromagnetic waves radiated by electronic instruments also have great potential harm to important systems such as precision instruments, aerospace engineering, navigation equipment, scientific measurement and medical care. Traditional electromagnetic shielding materials are mainly metal materials or polymer / metal composites. The metal materials have the advantages of high electromagnetic shielding efficiency, but have the disadvantages of heavy weight, easy corrosion and high price. The polymer / metal composites have the advantages of light weight, easy molding, corrosion resistance and low price, but have the disadvantages of non-recyclability, non-degradability and general electromagnetic shielding efficiency. Therefore, exploring green and environmentally friendly electromagnetic shielding materials with rich resources, renewability and degradability has become a research hotspot in the field of electromagnetic shielding. Wood, as a kind of natural green material for sustainable development, is a kind of biopolymer material with rich resources and biodegradability in nature, and is also a kind of natural material with the longest use time and the most extensive application. Compounding conductive components with wood is an effective way to prepare green and environmentally friendly electromagnetic shielding materials. Polyaniline is a cheap, light and easy-to-synthesize conductive polymer. Polyaniline wood electromagnetic shielding network can be constructed by filling polyaniline into wood, so as to prepare electromagnetic shielding wood with rich sources, low cost and biodegradability. Wang Zhongxiang (Wang Zhongxiang; Preparation and Performance Research of Electromagnetic Shielding Wood, Xi'an: Shaanxi University of Science and Technology, 2021) first treated wood with sodium chlorite, then immersed the treated wood in aniline solution and persulfate solution, and finally grew silver nanowires on the surface of the wood, to construct a sandwich structure electromagnetic shielding wood composed of two silver nanowire surface layers with good electrical conductivity and one polyaniline wood electromagnetic shielding network with relatively low electrical conductivity. Although the electromagnetic shielding wood has high electromagnetic shielding efficiency, there is no chemical bonding between wood, polyaniline and silver nanowires, and wood is prone to significant volume shrinkage and expansion with changes in environmental temperature and humidity. Therefore, during use, polyaniline and silver nanowires of the electromagnetic shielding wood are prone to falling off with changes in environmental temperature and humidity, resulting in reduced electromagnetic shielding efficiency. SUMMARY

[0003] The present application aims at the problem of poor electromagnetic shielding effectiveness stability of the electromagnetic shielding wood at present, and provides a preparation method of long-acting electromagnetic shielding solid wood board.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] The preparation method of long-acting electromagnetic shielding solid wood board is first vacuum pressure infusion treatment of solid wood board with phenyl trimethoxysilane ethanol solution, then impregnation treatment of solid wood board with aniline solution and ammonium persulfate solution respectively, then electrochemical treatment of solid wood board with aniline solution, and finally spray treatment of solid wood board with water-based polyurethane paint.

[0006] The preparation method of long-acting electromagnetic shielding solid wood board specifically comprises the following steps:

[0007] (1) The dried solid wood board sample is placed in an automatic vacuum pressure tank, vacuumized to a vacuum degree of 0.04-0.08 MPa, pressure maintained for 30-60 min, then phenyl trimethoxysilane ethanol solution with a weight percentage of 2-6 % is injected, pressurized to 0.5-1.0 MPa, pressure maintained for 30-60 min, and then pressure released; after continued immersion for 2-4 h under normal pressure, the solid wood board sample is taken out, air-dried at 60 ℃ for 24 h, and phenyl trimethoxysilane modified solid wood board sample is prepared;

[0008] (2) The phenyl trimethoxysilane modified solid wood board sample is first immersed in aniline solution for 1-2 h, air-dried at 60 ℃ for 12 h, then immersed in ammonium persulfate solution for 20-40 min, air-dried at 60 ℃ for 12 h, finally electrochemically treated in aniline solution for 30-60 min, and air-dried at 60 ℃ for 12 h, and polyaniline modified solid wood board sample is prepared;

[0009] (3) The polyaniline modified solid wood board sample is uniformly sprayed with water-based polyurethane paint, the spraying pressure is 0.2-0.6 MPa, the spraying time is 2-8 s, and after the sprayed solid wood board sample is placed at room temperature for 2-6 h, it is subjected to stepwise heating treatment, and the long-acting electromagnetic shielding solid wood board is prepared.

[0010] In the aniline solution, the concentration of aniline is 0.2-1.0 mol / L, the concentration of sulfuric acid is 0.1-2.0 mol / L, and the solvent is deionized water.

[0011] The concentration of ammonium persulfate in the ammonium persulfate solution is 0.5-2.0 mol / L, the concentration of sulfuric acid is 0.1-2.0 mol / L, and the solvent is deionized water.

[0012] The electrochemical treatment adopts a three-electrode system, takes a solid wood board sample as a working electrode, takes a platinum sheet as a counter electrode, takes a saturated calomel electrode as a reference electrode, takes an aniline solution as an electrolyte, utilizes a cyclic voltammetry oxidative polymerization reaction, and the voltage range is -0.2-1.2 V, and the scanning speed is 10-100 mV / s.

[0013] The water-based polyurethane coating is a water-based two-component polyurethane system, wherein the A component is a mixture of a water-based hydroxyl acrylate dispersion resin, a defoaming agent BYK-024, a leveling agent BYK-381, propylene glycol methyl ether acetate and a wetting agent TEGO-270, and the B component is a mixture of isophorone diisocyanate and propylene glycol methyl ether acetate.

[0014] The step heating treatment is divided into two stages of first-order heating and second-order heating, the first-order heating stage is heating to 60 DEG C, and the holding time is 40 min, and the second-order heating stage is heating to 90 DEG C, and the holding time is 20 min.

[0015] Compared with the prior art, the present application has the following advantages:

[0016] (1) In the present application, phenyl is grafted on wood fiber by the reaction of phenyl trimethoxysilane and the hydroxyl group of wood fiber, then the phenyl participates in the chemical polymerization or electrochemical polymerization reaction of aniline, and polyaniline and wood fiber are chemically bonded, finally, the reaction of isophorone diisocyanate of water-based polyurethane and the primary or secondary amino group of polyaniline molecule is carried out, and polyurethane and polyaniline are chemically bonded, therefore, the chemical bonding of wood fiber, polyaniline and polyurethane can significantly improve the bonding firmness of polyaniline and polyurethane on wood fiber, and can effectively prevent polyaniline and polyurethane from falling off when wood shrinks or expands.

[0017] (2) Because wood has poor conductivity, it cannot be directly used as a working electrode for cyclic voltammetry oxidative polymerization reaction, therefore, in the present application, conductive polyaniline is first formed on wood by chemical oxidative polymerization reaction, then the wood is used as a working electrode, a platinum sheet is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, an aniline solution is used as an electrolyte, and polyaniline is attached to wood by cyclic voltammetry oxidative polymerization reaction. Compared with chemical oxidative polymerization, the polyaniline prepared by cyclic voltammetry oxidative polymerization reaction is more uniform and dense, has better conductivity, and can cleverly fill the voids of wood, therefore, through cyclic voltammetry oxidative polymerization reaction, a uniform and dense polyaniline layer with high conductivity is formed on the surface of wood, which helps to improve the electromagnetic shielding efficiency of wood.

[0018] (3) The waterborne polyurethane coating is sprayed on the surface of the wood in the application, the waterproof polyurethane coating can not only effectively avoid the phenomenon of significant volume shrinkage and expansion of the wood caused by the evaporation or absorption of water due to the change of the external environmental temperature and humidity, and the falling off of polyaniline, but also can prevent the damage of water vapor, oxygen and ozone in the external environment to the molecular structure of polyaniline, and improve the electromagnetic shielding stability of the wood.

[0019] (4) Polyaniline can give the wood excellent electromagnetic shielding efficiency, and the chemical bonding of wood, polyaniline and polyurethane and the waterproof polyurethane coating can give the wood excellent electromagnetic shielding stability, therefore, the electromagnetic shielding solid wood board prepared by the application has high electromagnetic shielding efficiency and excellent electromagnetic shielding stability, the electromagnetic shielding efficiency of the electromagnetic wave with a frequency of 100MHz is 24.1-28.4 dB, and after 1 time, 10 times, 50 times and 100 times of hygrothermal aging treatment, the electromagnetic shielding efficiency is 23.9-28.4 dB, 23.3-27.7 dB, 21.4-26.3 dB and 17.7-22.8 dB respectively, which can effectively prevent the interference of external electromagnetic waves on precision instruments, scientific measurement, medical care and other systems, and has high economic value and social benefits. DETAILED DESCRIPTION

[0020] The advantages and effects of the technical solutions described in the application will be further described below through several groups of examples and comparative examples. It should be understood that the specific examples described herein are only used to explain the application and not to limit the application.

[0021] Example 1

[0022] (1) The dried solid wood board sample was placed in an automatic vacuum pressure tank, vacuumized to a vacuum degree of 0.06 MPa, and then a phenyl trimethoxysilane ethanol solution with a weight percentage of 4% was injected after pressure maintaining for 45 min, and the pressure was released after pressure maintaining for 45 min at 0.8 MPa; after continuing to immerse for 3 h at normal pressure, the solid wood board sample was taken out and air-dried at 60 ℃ for 24 h, to obtain a phenyl trimethoxysilane modified solid wood board sample;

[0023] (2) The phenyl trimethoxysilane modified solid wood board sample was first immersed in an aniline solution for 1.5 h, air-dried at 60 ℃ for 12 h, then immersed in an ammonium persulfate solution for 30 min, air-dried at 60 ℃ for 12 h, and finally electrochemically treated in an aniline solution for 45 min, air-dried at 60 ℃ for 12 h, to obtain a polyaniline modified solid wood board sample;

[0024] (3) uniformly spraying the polyphenylamine modified solid wood board sample with the water-based polyurethane coating, the spraying pressure is 0.4 MPa, the spraying time is 5 s, the solid wood board sample after spraying is placed at room temperature for 4 h, and then subjected to step heating treatment to obtain the long-acting electromagnetic shielding solid wood board.

[0025] The concentration of aniline in the aniline solution is 0.6 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0026] The concentration of ammonium persulfate in the ammonium persulfate solution is 1.2 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0027] The electrochemical treatment adopts a three-electrode system, the solid wood board sample is used as a working electrode, a platinum sheet is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, and an aniline solution is used as an electrolyte. The cyclic voltammetry oxidation polymerization reaction is used, the voltage range is-0.2-1.2 V, and the scanning rate is 50 mV / s.

[0028] The water-based polyurethane coating is a water-based two-component polyurethane system, wherein the A component is a mixture of a water-based hydroxyl acrylate dispersion resin, a defoaming agent BYK-024, a leveling agent BYK-381, propylene glycol methyl ether acetate, and a wetting agent TEGO-270, and the B component is a mixture of isophorone diisocyanate and propylene glycol methyl ether acetate.

[0029] The step heating treatment is divided into two stages of first-order heating and second-order heating. The first-order heating stage is heating to 60℃, and the holding time is 40 min. The second-order heating stage is heating to 90℃, and the holding time is 20 min.

[0030] Example 2

[0031] (1) The dried solid wood board sample is placed in an automatic vacuum pressure tank, vacuumized to a vacuum degree of 0.04 MPa, pressurized to 0.5 MPa after pressure maintaining for 30 min, and then pressure released. After continuing to immerse for 2 h at normal pressure, the solid wood board sample is taken out and air-dried at 60℃ for 24 h to obtain a phenyltrimethoxysilane modified solid wood board sample.

[0032] (2) The phenyltrimethoxysilane modified solid wood board sample is first immersed in an aniline solution for 1 h, air-dried at 60℃ for 12 h, then immersed in an ammonium persulfate solution for 20 min, air-dried at 60℃ for 12 h, and finally subjected to electrochemical treatment in an aniline solution for 30 min, air-dried at 60℃ for 12 h to obtain a polyphenylamine modified solid wood board sample.

[0033] (3) uniformly spraying the polyaniline modified solid wood board sample with the waterborne polyurethane coating, the spraying pressure is 0.2 MPa, the spraying time is 8 s, the sprayed solid wood board sample is placed at room temperature for 2 h, and then subjected to step heating treatment to obtain the long-acting electromagnetic shielding solid wood board.

[0034] The concentration of aniline in the aniline solution is 1.0 mol / L, the concentration of sulfuric acid is 2.0 mol / L, and the solvent is deionized water.

[0035] The concentration of ammonium persulfate in the ammonium persulfate solution is 2.0 mol / L, the concentration of sulfuric acid is 2.0 mol / L, and the solvent is deionized water.

[0036] The electrochemical treatment adopts a three-electrode system, the solid wood board sample is used as a working electrode, a platinum sheet is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, and an aniline solution is used as an electrolyte, a cyclic voltammetry oxidation polymerization reaction is used, the voltage range is-0.2~1.2 V, and the scanning rate is 10 mV / s.

[0037] The waterborne polyurethane coating is a waterborne two-component polyurethane system, wherein the A component is a mixture of a waterborne hydroxyl acrylate dispersion resin, a defoaming agent BYK-024, a leveling agent BYK-381, propylene glycol methyl ether acetate, and a wetting agent TEGO-270, and the B component is a mixture of isophorone diisocyanate and propylene glycol methyl ether acetate.

[0038] The step heating treatment is divided into two stages of first-order heating and second-order heating, the first-order heating stage is heating to 60℃, the holding time is 40 min, and the second-order heating stage is heating to 90℃, the holding time is 20 min.

[0039] Example 3

[0040] (1) The dried solid wood board sample is placed in an automatic vacuum pressure tank, vacuumized to a vacuum degree of 0.08 MPa, pressurized to 1.0 MPa after injecting a phenyl trimethoxysilane ethanol solution with a weight percentage of 6 % for 30 min, and then depressurized; after continuing to immerse for 4 h under normal pressure, the solid wood board sample is taken out and air-dried at 60℃ for 24 h to obtain a phenyl trimethoxysilane modified solid wood board sample;

[0041] (2) The phenyl trimethoxysilane modified solid wood board sample is first immersed in an aniline solution for 2 h, air-dried at 60℃ for 12 h, then immersed in an ammonium persulfate solution for 40 min, air-dried at 60℃ for 12 h, and finally subjected to electrochemical treatment in an aniline solution for 60 min, air-dried at 60℃ for 12 h to obtain a polyaniline modified solid wood board sample;

[0042] (3) uniformly spray the polyaniline modified solid wood board sample with the water-based polyurethane coating, the spraying pressure is 0.6 MPa, the spraying time is 2 s, the sprayed solid wood board sample is placed at room temperature for 6 h, and then subjected to the step heating treatment to obtain the long-acting electromagnetic shielding solid wood board.

[0043] The concentration of aniline in the aniline solution is 0.2 mol / L, the concentration of sulfuric acid is 0.1 mol / L, and the solvent is deionized water.

[0044] The concentration of ammonium persulfate in the ammonium persulfate solution is 0.5 mol / L, the concentration of sulfuric acid is 0.1 mol / L, and the solvent is deionized water.

[0045] The electrochemical treatment adopts a three-electrode system, the solid wood board sample is used as a working electrode, a platinum sheet is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, and an aniline solution is used as an electrolyte, a cyclic voltammetry oxidation polymerization reaction is used, the voltage range is-0.2-1.2 V, and the scanning rate is 100 mV / s.

[0046] The water-based polyurethane coating is a water-based two-component polyurethane system, wherein the A component is a mixture of a water-based hydroxyl acrylate dispersion resin, a defoaming agent BYK-024, a leveling agent BYK-381, propylene glycol methyl ether acetate, and a wetting agent TEGO-270, and the B component is a mixture of isophorone diisocyanate and propylene glycol methyl ether acetate.

[0047] The step heating treatment is divided into two stages of first-order heating and second-order heating, the first-order heating stage is heating to 60℃, and the holding time is 40 min, and the second-order heating stage is heating to 90℃, and the holding time is 20 min.

[0048] Comparative Example 1

[0049] (1) The dried solid wood board sample is first immersed in an aniline solution for 1.5 h, dried at 60℃ for 12 h, then immersed in an ammonium persulfate solution for 30 min, dried at 60℃ for 12 h, and finally subjected to electrochemical treatment in an aniline solution for 45 min, and dried at 60℃ for 12 h to obtain a polyaniline modified solid wood board sample.

[0050] (2) uniformly spray the polyaniline modified solid wood board sample with the water-based polyurethane coating, the spraying pressure is 0.4 MPa, the spraying time is 5 s, the sprayed solid wood board sample is placed at room temperature for 4 h, and then subjected to the step heating treatment to obtain the finished product.

[0051] The concentration of aniline in the aniline solution is 0.6 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0052] The concentration of ammonium persulfate in the ammonium persulfate solution is 1.2 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0053] The electrochemical treatment adopts a three-electrode system, takes the solid wood board sample as a working electrode, a platinum sheet as a counter electrode, a saturated calomel electrode as a reference electrode, and an aniline solution as an electrolyte, utilizes a cyclic voltammetry oxidation polymerization reaction, and has a voltage range of -0.2-1.2 V and a scanning rate of 50 mV / s.

[0054] The water-based polyurethane coating is a water-based two-component polyurethane system, wherein the A component is a mixture of a water-based hydroxyl acrylate dispersion resin, a defoaming agent BYK-024, a leveling agent BYK-381, propylene glycol methyl ether acetate, and a wetting agent TEGO-270, and the B component is a mixture of isophorone diisocyanate and propylene glycol methyl ether acetate.

[0055] The step heating treatment is divided into two stages of first-order heating and second-order heating, the first-order heating stage is heating to 60 DEG C, and the holding time is 40 min, and the second-order heating stage is heating to 90 DEG C, and the holding time is 20 min.

[0056] Comparative Example 2

[0057] (1) The dried solid wood board sample is placed in an automatic vacuum pressure tank, vacuumized to a vacuum degree of 0.06 MPa, pressure-maintained for 45 min, then a phenyl trimethoxysilane ethanol solution with a weight percentage of 4% is injected, pressure-maintained to 0.8 MPa for 45 min, and then pressure-released; after continuing to immerse for 3 h under normal pressure, the solid wood board sample is taken out, air-dried at 60 DEG C for 24 h, and a phenyl trimethoxysilane modified solid wood board sample is prepared;

[0058] (2) The phenyl trimethoxysilane modified solid wood board sample is first immersed in an aniline solution for 1.5 h, air-dried at 60 DEG C for 12 h, then immersed in an ammonium persulfate solution for 30 min, and air-dried at 60 DEG C for 12 h, and a polyaniline modified solid wood board sample is prepared;

[0059] (3) The polyaniline modified solid wood board sample is uniformly sprayed with a water-based polyurethane coating, the spraying pressure is 0.4 MPa, the spraying time is 5 s, the sprayed solid wood board sample is placed at room temperature for 4 h, then subjected to step heating treatment, and a finished product is prepared.

[0060] The concentration of aniline in the aniline solution is 0.6 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0061] The concentration of ammonium persulfate in the ammonium persulfate solution is 1.2 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0062] The water-based polyurethane coating is a water-based two-component polyurethane system, wherein the A component is a mixture of a water-based hydroxyl acrylate dispersion resin, a defoaming agent BYK-024, a leveling agent BYK-381, propylene glycol methyl ether acetate, and a wetting agent TEGO-270, and the B component is a mixture of isophorone diisocyanate and propylene glycol methyl ether acetate.

[0063] The step heating treatment is divided into two stages of first-order heating and second-order heating, the first-order heating stage is heating to 60 DEG C, and the holding time is 40 min, and the second-order heating stage is heating to 90 DEG C, and the holding time is 20 min.

[0064] Comparative Example 3

[0065] (1) The dried solid wood board sample is placed in an automatic vacuum pressure tank, vacuumed to a vacuum degree of 0.06 MPa, and then a 4% by weight phenyl trimethoxysilane ethanol solution is injected after pressure maintaining for 45 min, and the pressure is increased to 0.8 MPa, and the pressure is maintained for 45 min, and then the pressure is released; after continuing to soak for 3 h at normal pressure, the solid wood board sample is taken out, and dried at 60 DEG C for 24 h to obtain a phenyl trimethoxysilane modified solid wood board sample;

[0066] (2) The phenyl trimethoxysilane modified solid wood board sample is first immersed in an aniline solution for 1.5 h, dried at 60 DEG C for 12 h, then immersed in an ammonium persulfate solution for 30 min, dried at 60 DEG C for 12 h, and finally electrochemically treated in an aniline solution for 45 min, and dried at 60 DEG C for 12 h to obtain the finished product.

[0067] The concentration of aniline in the aniline solution is 0.6 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0068] The concentration of ammonium persulfate in the ammonium persulfate solution is 1.2 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0069] The electrochemical treatment adopts a three-electrode system, the solid wood board sample is used as the working electrode, the platinum sheet is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, and the aniline solution is used as the electrolyte, and the cyclic voltammetry oxidation polymerization reaction is used, the voltage range is-0.2~1.2 V, and the scanning rate is 50 mV / s.

[0070] Comparative Example 4

[0071] The dried solid wood board sample is first immersed in an aniline solution for 1.5 h, air-dried at 60 ℃ for 12 h, then immersed in an ammonium persulfate solution for 30 min, air-dried at 60 ℃ for 12 h, and finally electrochemically treated in an aniline solution for 45 min, air-dried at 60 ℃ for 12 h, to obtain the finished product.

[0072] In the aniline solution, the concentration of aniline is 0.6 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0073] In the ammonium persulfate solution, the concentration of ammonium persulfate is 1.2 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0074] Comparative Example 5

[0075] The dried solid wood board sample is first immersed in an aniline solution for 1.5 h, air-dried at 60 ℃ for 12 h, then immersed in an ammonium persulfate solution for 30 min, air-dried at 60 ℃ for 12 h, and finally electrochemically treated in an aniline solution for 45 min, air-dried at 60 ℃ for 12 h, to obtain the finished product.

[0076] In the aniline solution, the concentration of aniline is 0.6 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0077] In the ammonium persulfate solution, the concentration of ammonium persulfate is 1.2 mol / L, the concentration of sulfuric acid is 1.0 mol / L, and the solvent is deionized water.

[0078] The electrochemical treatment adopts a three-electrode system, the solid wood board sample is used as the working electrode, platinum is used as the counter electrode, saturated calomel electrode is used as the reference electrode, aniline solution is used as the electrolyte, cyclic voltammetry oxidation polymerization reaction is used, the voltage range is-0.2~1.2 V, and the scanning rate is 50 mV / s.

[0079] First, the sample is placed in a damp heat aging box with a temperature of 80 o C and a humidity of 90% RH for 12 h, and then the sample is placed in a damp heat aging box with a temperature of 80 o C and a humidity of 10% RH for 12 h, and the above process is repeated for 100 times. The electromagnetic shielding efficiency of the sample under the action of 100 MHz electromagnetic waves is tested according to GB / T 12190-2021, and the test results are shown in Table 1.

[0080] Table 1 Test results of electromagnetic shielding efficiency

[0081]

[0082] As can be seen from the test results of the three groups of examples and the five groups of comparative examples, the solid wood boards prepared in the three groups of examples have high electromagnetic shielding efficiency and excellent electromagnetic shielding efficiency stability, which shows that the solid wood boards can have high electromagnetic shielding efficiency and excellent electromagnetic shielding efficiency stability by using the phenyltrimethoxysilane solution to perform vacuum pressurized immersion treatment on the solid wood boards, then using the aniline solution and the ammonium persulfate solution to perform immersion treatment on the solid wood boards, then using the aniline solution to perform electrochemical treatment on the solid wood boards, and finally using the water-based polyurethane coating to perform spraying treatment on the solid wood boards.

[0083] The foregoing description shows and describes preferred embodiments of the present application. It is understood that the application is not limited to the embodiments disclosed, but is intended to cover any modifications which fall within the scope of the application encompassed by the claims, herein.

Claims

1. A method for preparing a long-lasting electromagnetically shielded solid wood board, characterized in that: First, the solid wood board is vacuum pressure impregnated with phenyltrimethoxysilane ethanol solution. Then, the solid wood board is impregnated with aniline solution and ammonium persulfate solution respectively. Next, the solid wood board is electrochemically treated with aniline solution. Finally, the solid wood board is sprayed with water-based polyurethane coating. Specifically, the following steps are included: (1) Place the dried solid wood board sample in an automatic vacuum pressure tank, evacuate to a vacuum degree of 0.04~0.08 MPa, maintain pressure for 30~60 min, inject 2~6% phenyltrimethoxysilane ethanol solution by weight, pressurize to 0.5~1.0 MPa, maintain pressure for 30~60 min, and release pressure; continue to immerse under normal pressure for 2~4 h, take out the solid wood board sample, and air dry at 60 ℃ for 24 h to obtain phenyltrimethoxysilane modified solid wood board sample; (2) The phenyltrimethoxysilane modified solid wood board sample was first soaked in aniline solution for 1-2 h, air-dried at 60 ℃ for 12 h, then soaked in ammonium persulfate solution for 20-40 min, air-dried at 60 ℃ for 12 h, and finally electrochemically treated in aniline solution for 30-60 min, and air-dried at 60 ℃ for 12 h to obtain the polyaniline modified solid wood board sample. (3) The polyaniline modified solid wood board sample was uniformly sprayed with water-based polyurethane coating. The spraying pressure was 0.2~0.6 MPa and the spraying time was 2~8 s. After the solid wood board sample was left to stand at room temperature for 2~6 h, it was subjected to step heating treatment to obtain the long-lasting electromagnetic shielding solid wood board.

2. The method for preparing long-lasting electromagnetic shielding solid wood board according to claim 1, characterized in that: The aniline solution contains aniline at a concentration of 0.2–1.0 mol / L, sulfuric acid at a concentration of 0.1–2.0 mol / L, and deionized water as the solvent.

3. The method for preparing long-lasting electromagnetic shielding solid wood board according to claim 1, characterized in that: The ammonium persulfate solution contains ammonium persulfate at a concentration of 0.5–2.0 mol / L, sulfuric acid at a concentration of 0.1–2.0 mol / L, and deionized water as the solvent.

4. The method for preparing long-lasting electromagnetic shielding solid wood board according to claim 1, characterized in that: The electrochemical treatment employs a three-electrode system, with the solid wood sample as the working electrode, a platinum sheet as the counter electrode, a saturated calomel electrode as the reference electrode, and an aniline solution as the electrolyte. Cyclic voltammetric oxidative polymerization is utilized, with a voltage range of -0.2 to 1.2 V and a scan rate of 10 to 100 mV / s.

5. The method for preparing long-lasting electromagnetic shielding solid wood board according to claim 1, characterized in that: The waterborne polyurethane coating is a waterborne two-component polyurethane system, wherein component A is a mixture of waterborne hydroxyl acrylic dispersion resin, defoamer BYK-024, leveling agent BYK-381, propylene glycol methyl ether acetate and wetting agent TEGO-270, and component B is a mixture of isophorone diisocyanate and propylene glycol methyl ether acetate.

6. The method for preparing long-lasting electromagnetic shielding solid wood board according to claim 1, characterized in that: The stepped heating process is divided into two stages: a first-stage heating and a second-stage heating. The first-stage heating involves heating to 60 °C and holding for 40 min, while the second-stage heating involves heating to 90 °C and holding for 20 min.

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