Important factors of nano powder dispersion

The so-called dispersion is generallyA two-phase system, in which one phase is composed of finely divided particles (usually in the colloidal size range) distributed throughout the entire large material. The particles are called dispersed phase or internal phase, while the large material is called continuous phase or external phase. Under natural conditions, this distribution is usually uneven, but under control, it can improve uniformity. The method is to add wetting agents or dispersants (surfactants) such as fatty acids. Different possible systems are: gas/solid (foam plastic); Liquid/gas (mist); Gas/liquid (foam); Solid/gas (smoke); Liquid/liquid (emulsion); Solid/liquid (paint); And solid/solid (carbon black in rubber). Some forms, such as milk and rubber slurry, are stabilized by the adhesion coating of protective colloids to prevent the aggregation of dispersed particles. The colloidal dispersion of solids in liquids (not strictly referred to as solutions) can be precipitated by neutralizing the charges on particles through the addition of electrolytes. Larger particles will gradually aggregate and rise or sink depending on their density.It includes three stages: 1. Wetting of ultrafine particles in liquid; 2. Aggregates are opened up under mechanical force to form independent primary particles or smaller aggregates; 3. Stabilize native particles or smaller aggregates to prevent re aggregation. In a sense, the dispersion treatment of nano powder is the key technology of zui in nano powder technology, and also an important link that must be solved in the application of nano materials.

Factors affecting the dispersion of nanomaterials:

1. Dispersing medium

(1) According to different viscosities, dispersing media are divided into three types: high viscosity, medium viscosity, and low viscosity. Nanomaterials are easily dispersed in low viscosity media such as water and organic solvents. Medium viscosity media such as liquid epoxy resin, liquid silicone rubber, etc., and high viscosity media such as molten plastics.

2. Dispersant

(1) The selection of dispersants is closely related to the structure, polarity, solubility parameters, and other properties of the dispersing medium.

(2) The dosage of dispersant is related to the specific surface area of nanomaterials and the functional groups modified by covalent bonds.

(3) In aqueous media, it is recommended to use TNWDIS. In strongly polar organic solvents such as alcohols DMF、NMP， Recommend using TNADIS.

3. Distributed equipment

Taicang Xide Machinery Technology Co., Ltd. specializes in the development of high shear three-stage dispersers XMD2000 series for the dispersion of nanomaterials. The XMD2000 series is suitable for large-scale dispersion of nano gas-phase silica (white carbon black), nano zinc oxide, nano cobalt oxide, nano iron oxide, nano bismuth oxide, nano ATO alloy and other products. Dispersion of a series of powders, liquids, and formulations including nano metal powders, carbon nanotubes, high-purity Al2O3, high-purity nano TiO2 series powders, super active nano TiO2 catalysts, nano TiO2 liquids, nano TiO2 silver antibacterial agents, nano high-purity ZrO2, ultrafine high-purity ZrO2, nano coating materials, nano silver antibacterial powders, nano SiO2, nano ZnO, photocatalysts, and nano three proof finishing agents in medium to low viscosity media.

From the perspective of equipment analysis, there are several factors that affect the dispersion results, including:

1. Form of dispersion head (batch and continuous) (continuous is better than batch)

2. Shear rate of dispersing head (the higher, the better the effect)

3 dispersed head tooth structure (divided into initial teeth, middle teeth, fine teeth, ultra-fine teeth, with fine teeth having better effect)

4. The residence time and dispersion time of materials in the dispersion chamber (can be regarded as the same motor, the smaller the flow rate, the better the effect)

5 cycles (the more, the better the effect, and by the end of the device's lifespan, it cannot be any better)

　

Key points for equipment selection:

1. Clearly define the desired effect and purpose of using the equipment

2. Detailed understanding and mastery of the properties of research materials (including physical and chemical properties)

3. Select the mixer for the equipment based on the material

4. Re determine the operating parameters and structural design of the equipment

5. Taking into account the overall cost of the equipment

XMD2000 series dispersion equipment applicable process:

Fine Chemicals Management:Pigments, fuels, coatings, paints, plastics, resins, inks, pastes, pastes, hot melt adhesives, flame retardants, adhesives, finishing agents, surfactants, dyeing agents, etc

Anti sticking agent, defoamer, brightener, rubber additive, plastic additive, fuel additive, flocculant, coagulant, surfactant, solvent, silicone oil emulsion, resin emulsion, carbon black dispersion, white carbon black

Petrochemical industry:Lubricating oil, heavy oil mixture, heavy oil emulsification, water in oil, oil-water, diesel emulsification, modified asphalt, emulsified asphalt, catalyst, wax emulsification

Pesticides and fertilizers:Fertilizer, pesticide emulsion, pesticide additive, pesticide intermediate, pesticide emulsion, insecticide, herbicide, seed coating agent, fungicide, plant hormone, urea, compound fertilizer, emulsion, wet powder

Biomedical:Cytoplasmization, serum vaccine, protein dispersant, drug cream, antibiotics, sugar coating, various types of syrup, nutrient solution, traditional Chinese patent medicines and simple preparations, paste medicine, biological products, cod liver oil, pollen, royal jelly, vaccine, various ointments, various oral liquids, injections, intravenous drip, etc

Daily chemical industry:Skin cream, skin cream, detergent, preservatives, hairdressing products, toothpaste, daily essence, shampoo, shoe polish, cosmetics, bath essence, soap, balm, etc

Food industry:Food additives, essence, spices, fruit juice, jam, ice cream, dairy products, chocolate, aloe, pineapple, sesame, moon cake filling, cream, juice, soybeans, soy sauce, bean paste, peanut milk, protein milk, soy milk, dairy products, malt cream、Tomato sauce, peanut butter, jelly, pudding, functional drinks, beer, chicken essence, seasonings, etc

Important factors of nano powder dispersion