Powder surface modification effect is not good? There may be several reasons for this!
Powder surface modification is a new technology that integrates powder processing, material processing, material properties, chemical industry, and machinery. Properties of raw materials, formulation of surface modifier, surface modification process, surface modification equipment, etc.
Properties of powder raw materials
The specific surface area, particle size and particle size distribution, specific surface energy, surface physical and chemical properties, and agglomeration of powder raw materials all have an impact on the modification effect, and are one of the important factors for selecting surface modifier formulations, process methods and equipment. one.
For example, the physical and chemical properties of the surface of the powder, such as surface electricity, wettability, functional groups or groups, dissolution or hydrolysis characteristics, etc., directly affect its interaction with the surface modifier molecules, thereby affecting the effect of its surface modification. At the same time, the physical and chemical properties of the surface are also one of the important considerations in selecting the surface modification process.
Surface Modifier Formulation
The surface modification of powder is largely achieved by the action of surface modifier on the surface of powder. Therefore, the formula (variety, dosage and usage) of the surface modifier has an important influence on the modification effect of the powder surface and the application performance of the modified product. The surface modifier formula is highly targeted, that is, it has the characteristics of “one key to open one lock”. The formulation of the surface modifier includes the selection of varieties, determination of dosage and usage, etc.
When selecting a surface modifier, the properties of the powder raw materials, the use or application field of the product, and the process, price, and environmental protection should be comprehensively considered, and the structure and properties of the surface modifier and its mechanism of action with the powder should be considered. , make a targeted selection.
Surface modification process
After the formulation of the surface modifier is determined, the surface modification process is one of the most important factors that determine the effect of surface modification. The surface modification process must meet the application requirements or application conditions of the surface modifier, have good dispersibility of the surface modifier, and can achieve uniform and firm coating of the surface modifier on the surface of the powder; at the same time, it requires a simple process and parameters. Good controllability, stable product quality, low energy consumption and low pollution.
Surface modification equipment
The surface modification or surface treatment technology of powder mainly includes surface modification methods, processes, surface modifiers and their formulations, and surface modification equipment. Among them, when the surface modification process and modifier formula are determined, the surface modification equipment becomes the key factor affecting the powder surface modification or surface treatment effect.
The performance of surface modification equipment does not depend on its rotational speed or complex structure. The key lies in the following basic process characteristics: 1. Dispersibility of powder and surface modifier; 2. Opportunities for contact or action; ③ modification temperature and residence time; ④ energy consumption and wear per unit product; ⑤ dust pollution; ⑥ equipment operation status.
A high-performance surface modifier should be able to make the powder and the surface modifier have good dispersibility, and equal opportunities for contact or action between the powder and the surface modifier, so as to achieve uniform single-layer adsorption and reduce the amount of modifier. At the same time, the modification temperature and reaction or residence time can be easily adjusted to achieve firm coating and complete evaporation of the solvent or diluent (if a solvent or diluent is used); in addition, the energy consumption and wear per unit product should be low, No dust pollution (powder spillage not only pollutes the environment, deteriorates working conditions, but also loses materials and increases production costs), the equipment is easy to operate and runs smoothly.