About powder surface modification technology
Powder surface modification refers to the use of physical, chemical, mechanical and other methods to treat the surface or interface of powder materials, and purposefully change the chemical properties of the surface of powder materials to meet the development of modern new materials, new processes and new technologies. need. It is a new technology that integrates powder processing, material processing, material properties, chemicals, and machinery.
The purpose of powder surface modification
Improve the dispersion, stability and compatibility of the powder particles; improve the chemical stability of the powder particles, such as drug resistance, light resistance, weather resistance, etc.; change the physical properties of the powder, such as optical effects, mechanical strength, etc. ; For the purpose of environmental protection and safe production.
Method for surface modification of powder
- Physical coating
The surface modification process of the powder by using surface modifiers such as polymers or resins to physically treat the surface of the powder.
- Chemical coating
A method of modifying the surface of particles by adsorption or chemical reaction.
- Precipitation coating
Using the precipitation reaction to form one or more layers of “coating” on the surface of the particles to achieve a method of improving the surface properties of the powder.
- Mechanochemical modification
Using ultrafine pulverization and other strong mechanical action to activate the powder surface.
- High energy modification
Using ultraviolet, infrared, corona discharge and plasma irradiation methods for surface treatment.
- Other surface modification methods
graft modification, acid-base treatment, chemical weather precipitation (CVD), physical precipitation (PVD).
Process of powder surface modification
- Dry process
The process is simple, and it is suitable for various organic surface modifiers, especially non-water-soluble various surface modifiers.
- Wet process
The surface modifier is well dispersed and the surface is evenly coated. It is suitable for various water-soluble or hydrolyzable organic surface modifiers, inorganic surface modifiers, etc.
- Combining crushing and surface modification into one process
The process is simple, and the crushing efficiency is improved to a certain extent, but the temperature is not easy to control, the coating rate is not high, and the surface modifier may be damaged.
- Combine drying and surface modification into one process
The process can be simplified, but the drying temperature is generally above 200 ℃, and it is difficult to ensure a uniform and firm coating.
ALPA’s powder surface modification equipment includes: Turbo mill, ULM-C series Rotor Mill, Three-roller Mill, Pin Mill, High-speed Blender.
Main factors affecting the surface modification effect of powder
- The nature of the powder raw material
Specific surface area, particle size, particle size distribution, specific surface energy, surface physical and chemical properties, agglomeration
- Surface modification process
The consideration factors are the characteristics of the surface modifier, such as water solubility, hydrolysis, boiling point or decomposition temperature, etc.; the process surface modification method of the front-stage crushing or powder preparation operation.
- Surface modifier formulation
variety, dosage and usage
- Surface modification equipment
The performance of the surface modification equipment depends on the characteristics of the selected process, not the speed of the speed or the complexity of the structure.
Application of powder surface modification technology
Organic/inorganic composite materials (plastics, rubber, etc.), paints, coatings, organic/inorganic composite materials, adsorption and catalytic materials, health and environmental protection, anti-agglomeration in the preparation of ultrafine and nanopowders.
Research direction of powder surface modification technology
- Surface modification process and equipment
Strengthen the research of surface modification process, improve technology, and update equipment to realize the monolayer adsorption of surface modifier on the particle surface, reduce the amount of modifier, stabilize product quality and facilitate operation.
- Surface modifier
On the one hand, it adopts advanced technology to reduce production costs, especially the cost of various coupling agents; on the other hand, it develops new surface modifiers with good application performance, low cost, and special properties or special functions.
- Powder surface modification “soft technology”
First, select powder materials and “design” the powder surface according to the performance requirements of the target material; secondly, use advanced calculation methods, calculation techniques and intelligent technologies to assist in the design of powder surface modification processes and modifier formulations. , In order to achieve the best application performance and application effect.
Article source: China Powder Network