CN101585959B - Conductive polymer absorbing material - Google Patents

Abstract

The invention belongs to the technical field of wave-absorbing materials, and particularly relates to a conductive polymer wave-absorbing material. The material is composed of poly (3, 4-dioxyethyl) thiophene (PEDOT) microspheres and organic binders such as epoxy resin or polyurethane, wherein the conductive polymer poly (3, 4-dioxyethyl) thiophene microspheres in the conductive polymer wave-absorbing material are 20-80% by mass. The conductive polymer wave-absorbing material has the outstanding advantages of thin coating, light weight and the like, has better wave-absorbing performance in a frequency band of 2-18 GHz, particularly has the maximum absorption of-21 dB at the frequency of 16GHz, and has good prospect as a radar wave-absorbing material.

Description

Conductive polymer absorbing material

technical field

The invention belongs to the technical field of wave-absorbing materials, in particular to conductive polymer wave-absorbing materials.

Background technique

Absorbing materials are a class of materials that can absorb electromagnetic wave energy projected onto its surface and convert it into heat energy through material loss. In recent years, with the development and deepening of research on radar absorbing materials, various new types of absorbing materials have emerged, aiming to improve the survival, penetration, and especially deep strike capabilities of stealth weapons. As a new type of wave-absorbing material, conductive polymer has a good application prospect in terms of meeting the requirements of thin material (layer), light (weight), wide (frequency) and strong (absorbing performance).

Conductive polymer refers to a polymer material that can conduct electricity after chemical or electrochemical doping with a л-conjugated long-chain structure. There are mainly polyaniline, polypyrrole, polythiophene, etc., which not only have the advantages of low density, light weight, easy processing, and low price of ordinary polymer materials, but also the conductivity can be adjusted between insulators, semiconductors, and conductors according to needs. Utilizing its electrical loss, it can be used as a wave-absorbing material, etc., which has attracted people's attention.

Chinese patent 03117132.X discloses that conductive polymer polyaniline is coated on magnetic particles Fe ₃ O ₄ , Fe ₂ O ₃ , Co ₂ O ₃ , and NiO, which has conductivity and magnetism, and gives a saturation magnetization value, but Absorbing performance data not available. Chinese patent 200610037966.8 discloses polyaniline-coated nano-TiO ₂ or TiO ₂ whiskers to modify cyanate ester, which increases dielectric loss without changing the dielectric constant and has certain wave-absorbing properties. Chinese patent 98111335.X discloses the preparation of polypyrrole/ferrite/polypyrrole composite film by electrochemical method, which has conductivity and magnetism, and the conductivity, tensile strength and saturation magnetization value of the film are given, but it does not The absorbing performance data are given. Chinese patent 03121536.X and Chinese patent 200410009428.9 respectively disclose that soft magnetic metal particles Fe, Co, Ni are coated with polyaniline and 95% of Fe, Co, Ni powder are blended with conductive polyaniline and organic binder as wave absorbing And electromagnetic shielding materials, the reflectivity is best up to -17dB, and the shielding is higher than 50dB in the frequency band less than 1.5GHz. The literature Polym.Adv.Tech. (2001, December, 1-7) reported the electromagnetic properties of conductive polyaniline with particle morphology and microtube morphology. Polyaniline with microtube morphology not only has electric loss but also magnetic loss, which can As a new type of absorbing material.

Poly(3,4-dioxyethyl)thiophene (PEDOT) in the family of conductive polymers has high conductivity, low bandgap width, and excellent stability, and has achieved commercial applications in antistatic coatings and solid capacitors , but there are no literature and patent reports as a wave-absorbing material.

Contents of the invention

The purpose of the present invention is to provide a conductive polymer wave-absorbing material with the advantages of light density and good wave-absorbing performance.

Another object of the present invention is to provide a method for preparing poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres, a conductive polymer wave-absorbing material.

The conductive polymer wave-absorbing material of the present invention is composed of poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres and organic binders such as epoxy resin or polyurethane, wherein the conductive polymer wave-absorbing material The mass percent content of the conductive polymer poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres is 20-80%.

Coat the obtained conductive polymer wave-absorbing material on a 2-5mm thick aluminum plate with a size of 180mm×180mm, and the coating amount is 0.5kg/m ² to 5kg/m ² , preferably 1kg/m ² to 3kg/m ^2. Curing and drying at 40-100°C after coating; testing its performance, the conductive polymer wave-absorbing material of the present invention has wave-absorbing performance in the 2-18GHz frequency band, and the maximum absorption (reflectivity) reaches -21dB.

The particle size of the poly(3,4-dioxyethyl)thiophene microspheres is between 50 nm and 10 μm, and the electrical conductivity is 1×10 ⁻⁴ to 100 S/cm.

The poly(3,4-dioxyethyl)thiophene microspheres are solid microspheres and/or hollow microspheres.

The particle size of the poly(3,4-dioxyethyl)thiophene solid microspheres is between 50 nm and 10 μm, and the electrical conductivity is between 1×10 ^-2 and 100 S/cm.

The particle size of the poly(3,4-dioxyethyl)thiophene hollow microspheres is between 100 nm and 10 μm, and the electrical conductivity is between 1×10 ^-4 and 10 S/cm.

The epoxy resin can be commercially available epoxy resin paint.

Described polyurethane can be commercially available polyurethane paint.

The preparation method of the conductive polymer wave-absorbing material of the present invention is: dispersing poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres in organic binders such as epoxy resin or polyurethane to obtain conductive polymer The wave-absorbing material, wherein the mass percentage of poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres in the conductive polymer wave-absorbing material is 20-80%.

Poly (3,4-dioxyethyl) thiophene (PEDOT) microsphere among the present invention is prepared by the method for emulsion polymerization, and this method comprises the following steps:

1) With water and acetonitrile mixed solution as solvent, the preparation mass concentration is the water-soluble polymer solution of 1%～10%, wherein: the volume ratio of water and acetonitrile is 1:2～20:1, preferably 2:1～ 5:1;

2) Add the oxidant to the water-soluble polymer solution prepared in step 1), stir to dissolve, the molar concentration of the oxidant in the water-soluble polymer solution is 1.0×10 ^-3 ~ 1.0 mol/L, and obtain the water-soluble polymer solution Mixture with oxidizing agent;

3) Under stirring conditions, add the acid dopant into the mixed solution obtained in step 2), the concentration of the acid dopant in the mixed solution is 0.1～0.5mol/L, after stirring evenly, add 3,4- Dioxyethylthiophene (EDOT), wherein: the molar weight of 3,4-dioxyethylthiophene (EDOT) added is 0.05～3 times of the oxidant molar weight added in step 2); Continuous stirring reaction at room temperature From 12 hours to 72 hours, a black emulsion containing solid microspheres of conductive polymer poly(3,4-dioxyethyl)thiophene (PEDOT) was obtained;

4) drying the black emulsion containing conductive polymer poly(3,4-dioxyethyl)thiophene (PEDOT) solid microspheres obtained in step 3) at 40-80°C to obtain a dark gray blocky solid; The solid was ground and passed through a 120-mesh sieve to obtain a dark gray powder; the dark gray powder was soaked in a mixed solvent of water and ethanol for 0.5 to 2 hours; then suction filtered, and rinsed with an appropriate amount of mixed solvent of water and ethanol until The eluate is basically colorless, and the obtained filter cake is vacuum-dried at 40-90° C. to obtain a black powder with graphite luster; the above-mentioned black powder is the conductive polymer poly(3,4- Dioxyethyl) thiophene (PEDOT) solid microspheres have a particle size between 50nm and 10μm, preferably 100nm and 2μm. Its conductivity is between 1×10 ^-2 and 100S/cm; or

a) Using water and acetonitrile mixture as solvent, prepare a water-soluble polymer solution with a mass concentration of 1% to 10%; wherein: the volume ratio of water to acetonitrile is 1:2 to 20:1, preferably 2:1 to 5:1;

b) adding the oxidizing agent to the water-soluble polymer solution prepared in step a), stirring and dissolving, the molar concentration of the oxidizing agent in the water-soluble polymer solution is 1.0×10 ^-3 ~ 1.0 mol/L, and obtaining the water-soluble polymer solution Mixture with oxidizing agent;

c) under agitation, add 3,4-dioxyethylthiophene (EDOT) to the mixed solution obtained in step b), wherein: the molar amount of 3,4-dioxyethylthiophene (EDOT) added It is 0.2 to 10 times the molar amount of the oxidizing agent added in step b); the stirring reaction is continued at room temperature for 12 hours to 72 hours, and the hollow microparticles containing conductive polymer poly(3,4-dioxyethyl)thiophene (PEDOT) are obtained. ball of black emulsion;

d) drying the black emulsion containing conductive polymer poly(3,4-dioxyethyl)thiophene (PEDOT) hollow microspheres obtained in step c) at 40-80°C to obtain a dark gray blocky solid; The solid was ground and passed through a 120-mesh sieve to obtain a dark gray powder; the dark gray powder was soaked in a mixed solvent of water and ethanol for 0.5 to 2 hours; then suction filtered, and rinsed with an appropriate amount of mixed solvent of water and ethanol until The eluate is basically colorless, and the obtained filter cake is vacuum-dried at 40-90° C. to obtain a black powder with graphite luster; the above-mentioned black powder is the conductive polymer poly(3,4- Dioxyethyl) thiophene (PEDOT) hollow microspheres, the particle size of which is between 100nm-10μm, preferably 200nm-2μm. Its conductivity is between 1×10 ^-4 and 10S/cm.

The water-soluble polymer includes polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) and the like.

Described oxidizing agent is, iron trichloride, chloroauric acid, ammonium persulfate or potassium persulfate etc.; Preferably ammonium persulfate is used when preparing conductive polymer poly (3,4-dioxyl) thiophene solid microspheres , ferric chloride or chloroauric acid; ammonium persulfate or potassium persulfate is used in the preparation of conductive polymer poly(3,4-dioxyethyl)thiophene hollow microspheres.

The acid dopant can be β-naphthalenesulfonic acid, p-toluenesulfonic acid or camphorsulfonic acid and the like.

The volume ratio of water to ethanol is 1:1.

The present invention utilizes the poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres prepared by the emulsion polymerization method as the radar wave-absorbing material, which is the main feature of the present invention. The conductive polymer wave-absorbing material of the present invention has outstanding advantages such as thin coating and light weight, and reaches the maximum absorption (reflectivity) of -21dB at a frequency of 16GHz.

Description of drawings

Fig. 1. SEM photo of poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres prepared in Example 1 of the present invention.

Fig. 2. SEM photo of poly(3,4-dioxyethyl)thiophene (PEDOT) microspheres prepared in Example 2 of the present invention.

Detailed ways

Example 1

1) A water-soluble polymer polyvinyl alcohol (PVA) solution with a mass concentration of 3% is prepared using a mixture of water and acetonitrile with a volume ratio of 10:1 as a solvent.

2) Add oxidant iron trichloride to the water-soluble polymer solution prepared in step 1), stir and dissolve, the molar concentration of ferric chloride in polyvinyl alcohol (PVA) aqueous solution is 0.05mol/L, obtain trichloride A mixture of iron and polyvinyl alcohol (PVA).

3) under stirring conditions, the acid dopant β-naphthalenesulfonic acid is added to the mixed solution obtained in step 2), the molar concentration of the acid dopant β-naphthalenesulfonic acid in the mixed solution is 0.3mol/L, After stirring evenly, add 3,4-dioxyethylthiophene (EDOT), wherein: the molar weight of the added 3,4-dioxyethylthiophene (EDOT) is the iron trichloride molar weight that adds in the step 2) 0.5 times. Stirring was continued at room temperature for 24 hours to obtain a black emulsion containing conductive polymer poly(3,4-dioxyethyl)thiophene (PEDOT) solid microspheres.

4) Dry the black emulsion in step 3) at 60° C. to obtain a dark gray blocky solid. The solid was ground and passed through a 120-mesh sieve to obtain a dark gray powder. Immerse this dark gray powder in the mixed solvent of water and ethanol (volume ratio is 1: 1) that is 20 times of its mass and soak for 2 hours, then suction filter, and with the mixed solvent of appropriate amount of water and ethanol (volume ratio is 1: 1) 1) Rinse until the eluent is basically colorless, and the obtained filter cake is vacuum-dried at 70° C. to obtain a black powder with graphite luster, that is, the conductive polymer poly(3,4-dioxyethyl)thiophene ( PEDOT) solid microspheres, its scanning electron micrograph is shown in Figure 1, and the particle is a spherical shape with uniform particle size, the particle diameter is about 100nm, and the surface is slightly rough. The conductivity was measured to be 3.8 S/cm.

5) Disperse the poly(3,4-dioxyethyl)thiophene (PEDOT) solid microspheres prepared in step 4) in an epoxy resin binder to obtain a conductive polymer wave-absorbing material, wherein poly(3,4- The mass percent content of dioxyethyl)thiophene (PEDOT) is 30%. Coat this absorbing material on a 3mm thick aluminum plate with a size of 180mm×180mm. The coating amount is 1kg/ ^m2 . After coating, it is cured and dried at 80°C. The film thickness is about 1mm. It has a certain absorbing performance, and the reflectance is -5dB at the peak of 5GHz.

Example 2

1). The mixture of water and acetonitrile with a volume ratio of 5:1 is used as a solvent to prepare a 5% polyvinylpyrrolidone (PVP) solution with a mass concentration.

2). Add ammonium persulfate as oxidant in the polyvinylpyrrolidone (PVP) solution prepared in step 1), stir and dissolve evenly, the molar concentration of ammonium persulfate in the solution is 0.1mol/L, and obtain ammonium persulfate and polyethylene Pyrrolidone (mixture of PVP.

3) Under stirring conditions, add 3,4-dioxyethylthiophene (EDOT) to the mixed solution obtained in step 2), wherein: the molar amount of 3,4-dioxyethylthiophene (EDOT) added It is 2 times the molar amount of ammonium persulfate added in step 2), and the stirring reaction is continued at room temperature for 72 hours to obtain a black emulsion containing poly(3,4-dioxyethyl)thiophene (PEDOT) hollow microspheres.

4) Dry the black emulsion in step 3) at 40° C. to obtain a dark gray blocky solid. The solid was ground and passed through a 120-mesh sieve to obtain a dark gray powder. Immerse this dark gray powder in the mixed solvent of water and ethanol (volume ratio is 1: 1) of 20 times its mass and soak for 1 hour, then suction filter, and use the mixed solvent of appropriate amount of water and ethanol (volume ratio is 1: 1) 1) Rinse until the eluent is basically colorless, and the obtained filter cake is vacuum-dried at 50° C. to obtain a black powder with graphite luster, that is, the conductive polymer poly(3,4-dioxyethyl)thiophene ( PEDOT) hollow microspheres, the scanning electron microscope photo is shown in Figure 2, the particles are hollow microspheres, the surface is smooth, and some particles are concave and deflated, and the particle size is about 500nm-1.2μm. The measured conductivity was 1.3×10 ^-1 S/cm.

5). The poly(3,4-dioxyethyl)thiophene (PEDOT) hollow microspheres obtained in step 4) are evenly dispersed in polyurethane paint to obtain a conductive polymer wave-absorbing material, wherein poly(3,4 -Dioxyethyl) thiophene (PEDOT) microspheres have a mass percentage concentration of 50%, which are coated on a 3mm thick aluminum plate with a size of 180mm×180mm, and the coating amount is 2kg/m ² . The thickness of the cured and dried film at 70°C is about 2mm, and the reflectivity is above -10dB in the wide frequency band of 13.0-18GHz. Among them, the reflectivity can reach -21dB at the maximum absorption of 16GHz, showing excellent wave-absorbing performance.

Example 3

1) A water-soluble polymer polyvinylpyrrolidone (PVP) solution with a mass concentration of 2% is prepared by using a mixture of water and acetonitrile with a volume ratio of 6:1 as a solvent.

2) in the water-soluble macromolecule solution of step 1) adding oxidant chloroauric acid, stirring and dissolving, the molar concentration of chloroauric acid in polyvinylpyrrolidone (PVP) aqueous solution is 0.3mol/L, obtains chloroauric acid and polyvinylpyrrolidone (PVP) aqueous solution A mixture of vinylpyrrolidone (PVP).

3) Under stirring conditions, add the acid dopant p-toluenesulfonic acid into the mixed solution obtained in step 2), the molar concentration of the acid dopant p-toluenesulfonic acid in the mixed solution is 0.1mol/L, stir well Afterwards, add 3,4-dioxyethylthiophene (EDOT), wherein: the molar weight of the 3,4-dioxyethylthiophene (EDOT) that adds is the 3rd of the iron trichloride molar weight that adds in the step 2) times. Stirring was continued at room temperature for 48 hours to obtain a black emulsion containing solid microspheres of conductive polymer poly(3,4-dioxyethyl)thiophene (PEDOT).

4) Dry the black emulsion in step 3) at 50° C. to obtain a dark gray blocky solid. The solid was ground and passed through a 120-mesh sieve to obtain a dark gray powder. Immerse this dark gray powder in the mixed solvent of water and ethanol (volume ratio is 1: 1) that is 20 times of its mass and soak for 2 hours, then suction filter, and with the mixed solvent of appropriate amount of water and ethanol (volume ratio is 1: 1) 1) Rinse until the eluent is basically colorless, and the obtained filter cake is vacuum-dried at 50° C. to obtain a black powder with graphite luster, that is, the conductive polymer poly(3,4-dioxyethyl)thiophene ( PEDOT) solid microspheres, the particles are spherical with uniform particle size, the particle diameter is about 130nm, and the measured electrical conductivity is 6.3S/cm. spare.

5). Using a mixture of water and acetonitrile with a volume ratio of 8:1 as a solvent, prepare a polyvinyl alcohol (PVA) solution with a mass concentration of 4%.

6). In the polyvinyl alcohol (PVA) solution prepared in step 5), potassium persulfate is added as an oxidizing agent, stirred and dissolved evenly, and the molar concentration of potassium persulfate in the solution is 0.1mol/L to obtain potassium persulfate and polyethylene Alcohol (PVA) mixture.

7) Under stirring conditions, add 3,4-dioxyethylthiophene (EDOT) to the mixed solution obtained in step 6), wherein: the molar amount of 3,4-dioxyethylthiophene (EDOT) added It is 6 times the molar amount of ammonium persulfate added in step 2), and the stirring reaction is continued at room temperature for 24 hours to obtain a black emulsion containing poly(3,4-dioxyethyl)thiophene (PEDOT) hollow microspheres.

8) Dry the black emulsion in step 7) at 40° C. to obtain a dark gray blocky solid. The solid was ground and passed through a 120-mesh sieve to obtain a dark gray powder. Immerse this dark gray powder in the mixed solvent of water and ethanol (volume ratio is 1: 1) of 20 times its mass and soak for 1 hour, then suction filter, and use the mixed solvent of appropriate amount of water and ethanol (volume ratio is 1: 1) 1) Rinse until the eluent is basically colorless, and the obtained filter cake is vacuum-dried at 60° C. to obtain a black powder with graphite luster, that is, the conductive polymer poly(3,4-dioxyethyl)thiophene ( PEDOT) hollow microspheres with a smooth surface, a particle size of about 700nm to 1.0μm, and a measured electrical conductivity of 1.9×10 ^-2 /cm. spare.

9). The poly(3,4-dioxyethyl)thiophene (PEDOT) solid microspheres obtained in step 4) and the poly(3,4-dioxyethyl)thiophene (PEDOT) hollow microspheres obtained in step 8) The microspheres are uniformly dispersed in the polyurethane paint to obtain a conductive polymer wave-absorbing material, wherein the mass percent concentration of poly(3,4-dioxyethyl)thiophene (PEDOT) solid microspheres is 20%, poly(3, The mass percent concentration of 4-dioxyethyl)thiophene (PEDOT) hollow spheres is 40%, which is coated on a 3mm thick aluminum plate with a size of 180mm×180mm, and the coating amount is about 3kg/m ² . After curing at 70°C, the thickness of the dry film is about 3mm, and the reflectivity is above -10dB in the wide frequency band of 8.0-14GHz. Among them, the reflectivity can reach -17dB at the maximum absorption of about 10GHz, showing excellent wave-absorbing performance.

Claims (3)

1. conductive polymer wave-absorbing material, it is characterized in that, this material is by poly-(3, the 4-dioxoethyl) thiophene tiny balloon and Resins, epoxy or urethane organic binder bond are formed, wherein the quality percentage composition of the conductive polymer poly in the conductive polymer wave-absorbing material (3, the 4-dioxoethyl) thiophene tiny balloon is 20～80%;

Described poly-(3, the 4-dioxoethyl) thiophene tiny balloon prepares by method of emulsion polymerization, and this method may further comprise the steps:

A) be solvent with water and acetonitrile mixed solution, the preparation mass concentration is 1%～10% water-soluble polymer solution; Wherein: the volume ratio of water and acetonitrile is 1: 2～20: 1;

B) oxygenant is joined in the water-soluble polymer solution of step a) preparation, stirring and dissolving, the volumetric molar concentration of oxygenant in water-soluble polymer solution is 1.0 * 10 ^-3～1.0mol/L obtains water-soluble polymer solution and oxygenant mixed solution;

C) under agitation condition, with 3,4-dioxoethyl thiophene joins in the mixed solution that step b) obtains, wherein: 3 of adding, the molar weight of 4-dioxoethyl thiophene are 0.2～10 times of the oxygenant molar weight that adds in the step b); At room temperature continue stirring reaction, obtain containing the emulsion of conductive polymer poly (3, the 4-dioxoethyl) thiophene tiny balloon;

D) emulsion that contains conductive polymer poly (3, the 4-dioxoethyl) thiophene tiny balloon that step c) is obtained obtains solid 40～80 ℃ of oven dry down; This solid is ground, cross 120 mesh sieves, obtain powder; To soak in this powder immersion and the ethanol mixed solvent; Suction filtration, and water then and alcohol mixed solvent drip washing, the filter cake that obtains obtain conductive polymer poly (3, the 4-dioxoethyl) thiophene tiny balloon at 40～90 ℃ of following vacuum dryings;

The particle diameter of described poly-(3, the 4-dioxoethyl) thiophene tiny balloon is between 100nm～10 μ m, and specific conductivity is 1 * 10 ^-4Between～the 10S/cm.

2. conductive polymer wave-absorbing material according to claim 1, it is characterized in that: described by poly-(3, the 4-dioxoethyl) conductive polymer wave-absorbing material of thiophene tiny balloon and Resins, epoxy or urethane organic binder bond composition is on 2～18GHz frequency band, have absorbing property, maximum absorption reaches-21dB.

3. conductive polymer wave-absorbing material according to claim 1 is characterized in that: described water-soluble polymer is polyvinyl alcohol, polyvinylpyrrolidone or polyoxyethylene glycol;

Described oxygenant is iron trichloride, hydrochloro-auric acid, ammonium persulphate or Potassium Persulphate.

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