KR100394082B1 - Anhydrous electrorheological fluids included chitosan dicarboxylate and preparation method of thereof - Google Patents

Abstract

The present invention relates to an anhydrous electrorheological fluid containing chitosan dicarboxyl salt and a method for preparing the same, and more particularly, to chitosan dicarboxylate microparticles prepared by catalytic reaction of chitosan and dicarboxylic acid. The present invention relates to an anhydrous electrorheological fluid having improved electrorheological properties, dispersion stability, corrosion resistance, abrasion resistance, environmental friendliness and high temperature stability compared to the prior art by preparing an electrorheological fluid by dispersing, and a method of manufacturing the same. .

Description

Anhydrous electrorheological fluids included chitosan dicarboxylate and preparation method of

The present invention relates to an anhydrous electrorheological fluid containing chitosan dicarboxyl salt and a method for preparing the same, and more particularly, to chitosan dicarboxylate microparticles prepared by catalytic reaction of chitosan and dicarboxylic acid. The present invention relates to an anhydrous electrorheological fluid having improved electrorheological properties, dispersion stability, corrosion resistance, abrasion resistance, environmental friendliness and high temperature stability compared to the prior art by preparing an electrorheological fluid by dispersing, and a method of manufacturing the same. .

An electrorheological fluid is a colloidal liquid in which fine particles, such as inorganic and organic compounds, are polarized in insulating fluids such as synthetic oil, mineral oil and vegetable oil. (Bingham flow), but when the electric field is removed it has the characteristic of reducing to the original liquid phase. This is because polar particles dispersed in an insulating fluid under an electric field form a chain or fiber structure connecting the electrodes.

This electrical rheological effect was discovered by Winslow (W) in 1947 and is well known today as the Winslow effect. Conventional electrorheological fluids include polar organics such as water and alcohol in inorganic and organic rheological materials such as corn starch (US Pat. No. 2,417,508), silica (US Pat. No. 3,407,507), and zeolite (US Pat. No. 4,702,855). A hydrous electrorheological fluid consisting of a composition containing a small amount of solvent and dispersed in insulating fluids such as silicone and mineral oil. They are electrolyzed by polar solvents such as water and alcohol. It has many problems such as wear resistance, corrosion resistance, high temperature stability and unstable rheological properties.

In order to solve the above problems with conventional aqueous electrofluidic fluids, anhydrous electrofluidic fluids containing no polar organic solvent have recently been developed. They are dispersed in base oil by the synthesis of polymer materials such as copolymers of styrene and maleic acid (US Pat. No. 4,992,192), polyaniline (UK Patent Application A8900825.6 and 9313408.8), and polyurethane (US Pat. No. 5,268,118). Was prepared. The rheological materials of the anhydrous electrorheological fluids have polar groups such as amine group (-NH ₂ ), amine cyanide group (-NHCN) and carboxyl group (-COOH). Even if they do not contain them, they are activated under an electric field and thus exhibit an electrorheological effect. The recently developed anhydrous electrorheological fluids have improved instability of the electrorheological properties due to evaporation of polar solvents and corrosion and abrasion resistance of the device, compared to conventional aqueous electrorheological fluids, but dispersion stability and high temperature stability are still insufficient. . In addition, since the rheological materials are composed of synthetic polymers, they are frequently pressed to the electrode, which causes a large problem of reducing the quick response and the electric rheological effect.

The present invention has completed the present invention by using chitosan dicarboxyl salt showing excellent electric rheological effect under an electric field as a rheological material.

Accordingly, an object of the present invention is to provide an anhydrous electrorheological fluid having excellent performances such as electric rheological properties, dispersion stability, abrasion resistance, corrosion resistance, high temperature stability and biodegradability, and a method of manufacturing the same.

The present invention is characterized by an anhydrous electrorheological fluid consisting of 1 to 50% by weight of chitosan dicarboxylate and 50 to 99% by weight of base oil.

The present invention is to prepare a chitosan dicarboxyl salt by reacting chitosan, dicarboxylic acid and catalyst in dimethylformamide for 1 to 24 hours at room temperature and 1 to 50% by weight of the chitosan dicarboxylic salt produced in the step and A method for producing an anhydrous electrorheological fluid consisting of mixing 50 to 99% by weight of base oil at a temperature of 30 to 80 ° C.

Referring to the present invention in more detail as follows.

Chitosan dicarboxylate is synthesized by amide reaction of chitosan and dicarboxylic acid in the presence of a catalyst, and the synthesized chitosan dicarboxylate has amide (-CONH) and shows excellent electrorheological effect under electric field. It is preferable to contain 1-50 weight% in an electrorheological fluid. If the content is less than 1% by weight, the electric rheological effect is low. If the content is more than 50% by weight, the initial viscosity is high, so that the system is not easily controlled. In addition, the chitosan dicarboxylate salt is preferably used having an average particle diameter of 1 to 30 μm, if the particle diameter is less than 1 μm, there is a problem in the electrorheological effect, if it exceeds 30 μm there is a problem in dispersion stability. . Chitosan used for the amide reaction of chitosan and dicarboxylic acid is a natural biopolymer obtained by deacetylation of chitin obtained from shells of shrimp, crabs and the like and is an environmentally friendly material. In addition, dicarboxylic acid is preferably used in the range of 4 to 25 carbon atoms, such as malonic acid, adipic acid, azelic acid, succinic acid and the like. Triphenylphosphine (hereinafter referred to as TPP) and diethylazodicarboxylate (hereinafter referred to as DEAD) may be used as a catalyst.

Mineral oil, synthetic oil, vegetable oil, etc. can be used as a base oil, and it is preferable to contain 50-99 weight% of all the electrorheological fluids. As the synthetic oil, silicone oil, diesters, polyalphaolefin oil and fluoro synthetic hydrocarbon-based synthetic oil may be used, and as the vegetable oil, corn oil, palm oil, olive oil and sunflower oil may be used.

Referring to the manufacturing method of the anhydrous electrorheological fluid of the present invention are as follows.

First, as shown in the following Scheme 1, 0.1 to 3 mol of dicarboxylic acid, 0.01 to 0.1 mol of catalyst and 60 to 120 g of chitosan are added to 1ι dimethylformamide (hereinafter referred to as DMF) and reacted at room temperature for 1 to 24 hours. Chitosan dicarboxylate is obtained. Then, 1 to 50% by weight of the chitosan dicarboxyl salt prepared above and 50 to 99% by weight of base oil are mixed at a temperature of 30 to 80 ° C for 0.5 to 3 hours to prepare an anhydrous electrorheological fluid.

As described above, the anhydrous electrorheological fluid according to the present invention improves performances such as dispersion stability, abrasion resistance, high temperature stability, and instability of the electrorheological effect due to adhesion to electrodes, which are problems of conventional electrorheological fluids. It also has biodegradability and has an environmentally friendly effect.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Examples 1 to 4 and Comparative Example 1. Electrorheological fluid composed of chitosan malonate according to the molar ratio of malonic acid

Chitosan (100 g) and the reaction catalyst (TPP 0.02 mol and DEAD 0.02 mol) were fixed in order to confirm the electrorheological properties of chitosan malonate according to the amount of malonic acid added. Was prepared. In the method of preparing an electrorheological fluid, chitosan, a reaction catalyst, and malonic acid were first added to a DMF solution and reacted at room temperature for 8 hours. After the reaction, the resulting chitosan malonate was washed with DMF solution and distilled water and dried in an oven at 100 ° C. The dried chitosan malonate was ground to a particle size of 1 to 30 μm in a ball mill vessel and re-dried in an oven at 100 ° C. Then, 30 wt% of the prepared chitosan malonate powder and 70 wt% of silicone oil having a viscosity of 50 cst were placed in a ball mill container and mixed at 50 ° C. for 1 hour to prepare an electrorheological fluid (Examples 1 to 4).

As a comparative example, an electrorheological fluid was prepared using only silicone oil without containing chitosan malonate.

The electro-fluidic fluids of Examples 1 to 4 and Comparative Example 1 prepared above were measured for physical properties by the following test methods, and the results are shown in Table 1 below.

<Test method>

1. Yield stress: measured using a Physica Reometer (Physica Reometer, Germany) at an oil temperature of 25 ℃, electric field 3kV / mm and shear strain 10s ^-1 .

2. Wear resistance: measured by ASTM D2266 method.

3. Biodegradability: evaluated by CEC-L-33-T-82 test method.

4. Dispersion Stability: After 30 days, it was measured using a Physica Reometer (Physica Reometer, Germany) under an oil temperature of 25 ° C., an electric field of 3 kV / mm and a shear strain of 10 s ⁻¹ .

5. Corrosion: measured by ASTM D2451 method.

6. High temperature stability: It was measured under the electric field of 3kV / mm and shear strain 10s ^-1 using a Physica Reometer (Physica Reometer, Germany) at oil temperature 40 ℃, 80 ℃ and 100 ℃.

As shown in Table 1, Comparative Example 1, which does not contain chitosan malonate, showed almost zero yield stress under an electric field, but Examples 1 to 4 containing chitosan malonate increased the yield stress. there was. In addition, the yield stress values of the electrorheological fluids containing chitosan malonate reacted at least 0.5 moles of malonic acid in the above example were almost similar, and it was found that the amide reaction of chitosan was saturated at 0.5 moles or more of malonic acid.

Examples 5 to 7 Electro-Rheological Fluids Comprising Chitosan Malonate According to the Molar Ratio of Reaction Catalyst

Chitosan (100 g) and malonic acid (0.5 mole) were fixed to confirm the electrorheological properties of chitosan malonate according to the reaction catalyst, and the amounts of TPP and DEAD as reaction catalysts were changed as shown in Table 2 below. Electrophoretic fluid was prepared by the method of preparation 1, and the physical properties of the prepared electrofluidic fluid were measured by the same method as in Example 1, and the results are shown in Table 2.

Examples 8 to 10. Electrorheological fluids composed of chitosan dicarboxylic salts according to the type of dicarboxylic acid.

In order to confirm the electrorheological properties of the chitosan dicarboxylate according to the type of dicarboxylic acid, chitosan (100 g) and the reaction catalyst (TPP 0.02 mole and DEAD 0.02 mole) were fixed and dicarboxyl as shown in Table 3 below. The rheological fluid was prepared by changing the type of acid (0.5 mole), and the physical properties were measured by the same method as in Example 1. Indicated.

As shown in Table 3, Examples 2, 8 to 10 according to the present invention was confirmed that the excellent electrical rheological properties such as yield stress, wear resistance, biodegradability and dispersibility. As the carbon number of the dicarboxylic acid increases, the yield stress value decreases. This is due to the decrease in the degree of polarity under the electric field.

Examples 11 to 13. Electrorheological Fluids According to Types of Base Oils

Chitosan (100 g), maleic acid (0.5 mole), and reaction catalyst (0.02 mole of TTP and 0.02 mole of DEAD) were fixed in order to confirm the electrorheological properties of the electrofluidic fluid according to the type of base oil. By changing the type of base oil (70% by weight) as described above, an electro- rheological fluid was prepared by the method of Example 1, and the properties of the prepared electro-fluidic fluid were measured by the same method as in Example 1, and the results are shown in Table 1 below. 4 is shown.

As shown in Table 4, it was confirmed that the electrorheological fluids of Examples 2 and 11 and 13 according to the present invention had excellent electric rheological properties such as yield stress, wear resistance, and dispersibility.

Example 14 Electro-Rheological Fluid with Contents of Chitosan Maleic Salt and Base Oil

Chitosan Maleic Salt by Fixing Chitosan (100g), Malinic Acid (0.5mol), and Reaction Catalyst (TPP 0.02mol and DEAD 0.02mol) in order to confirm the electrorheological properties of the rheological fluid according to the chitosan maleic salt and base oil content Was prepared. Then, as shown in Table 5 below, the contents of the chitosan maleic salt and the base oil were changed to prepare an electrorheological fluid using the preparation method of Example 1, and the prepared electrorheological fluid was prepared by the same method as in Example 1. Physical properties were measured and the results are shown in Table 5.

As shown in Table 5, it was confirmed that the electrorheological fluids of Examples 2 and 14 according to the present invention have excellent electrical rheological properties such as yield stress, wear resistance, and dispersibility.

Test Example

The electrorheological fluid of Example 2 according to the present invention is compared with a German product (Bayer, composition: polyurethane and silicone oil, Comparative Example 2) having excellent performance among commercially available products, and the results are shown in Table 6 below. It was.

As shown in Table 6, Example 2 according to the present invention was confirmed that the excellent electrical rheological properties such as high temperature stability, wear resistance, biodegradability and dispersibility than the conventional Comparative Example 2. This is because the rheological material of Comparative Example 2 is composed of synthetic polymer such as polyurethane, so that adhesion phenomenon occurs to the electrode under electric field.

As described above, the anhydrous electrorheological fluid according to the present invention is composed of a rheological material and a base oil of chitosan dicarboxylate, and has excellent performances such as electric rheological properties, dispersion stability, corrosion resistance, abrasion resistance, environmental friendliness and high temperature stability. It can be usefully used in various fields such as automobile component parts such as shock absorbers, dampers, clutches and actuators, and electronic parts such as printers, copiers and washing machines.

Claims (9)

An anhydrous electrorheological fluid comprising 1 to 50% by weight of chitosan dicarboxylate and 50 to 99% by weight of base oil. The anhydrous electrolying fluid according to claim 1, wherein the chitosan dicarboxylic salt is produced by a catalytic reaction of chitosan and dicarboxylic acid. The anhydrous electrorheological fluid according to claim 1 or 2, wherein the chitosan dicarboxylate has an average particle diameter of 1 to 30 µm. 3. The anhydrous electrophilic fluid according to claim 2, wherein the dicarboxylic acid is selected from malonic acid, adipic acid, azelinic acid and rosinic acid having 4 to 20 carbon atoms. 3. Anhydrous electrophilic fluid according to claim 2, wherein the catalyst is triphenylphosphine and diethylazodicarboxylate. 2. The anhydrous electrorheological fluid according to claim 1, wherein the base oil is selected from mineral oil, vegetable oil and synthetic oil. 1) adding chitosan, dicarboxylic acid and catalyst in dimethylformamide to react at room temperature for 1 to 24 hours to obtain a chitosan dicarboxylic salt; and 2) mixing 1 to 50% by weight of the chitosan dicarboxyl salt and 50 to 99% by weight of the base oil produced in step 1 at a temperature of 30 to 80 ° C; Method for producing an anhydrous electrorheological fluid, characterized in that consisting of. 8. The method of claim 7, wherein the first step comprises 60 to 120 g of chitosan, 0.1 to 3 moles of dicarboxylic acid, and 0.01 to 0.1 moles of catalyst. 8. The method of claim 7, wherein the catalyst is triphenylphosphine and diethyl azodicarboxylate.