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Barium sulfate board manufacturers talk about common surface modification methods of barium sulfate sand
- 2020-08-11-

Barium sulfate board manufacturers talk about common surface modification methods of barium sulfate sand


1. Mechanochemical modification method


Barium sulfate board manufacturers talk about mechanochemical modification that uses the process of ultra-fine grinding and other strong mechanical effects to purposefully activate the surface of the powder, to a certain extent, change the crystal structure of the particle surface, and the solubility of the micro surface is amorphous) Chemical adsorption and reactive turbidity increase surface active sites or active genes). Obviously, only relying on mechanical activation for surface treatment is still difficult to meet the requirements of physical and chemical properties of BaSO4 in powder coatings. However, the mechanochemical action activates the surface of the particles, which can improve the activity of BaSO4 with other organics. The free radicals or ions generated on the new surface can initiate the polymerization of styrene and olefins to form polymer grafted fillers. In addition, you can also add an inorganic substance or metal powder in the pulverization process to make BaSO; the surface of the core material is coated with metal powder or another kind of inorganic powder, which can greatly improve the performance of BaSO4 in powder coatings.


2. Encapsulation modification method


Encapsulation modification is a surface modification method in which a homogeneous and thick film is covered on the surface of BaSO4 particles. The encapsulation modification of powder refers to the encapsulation of micro particles. This kind of tiny capsule is generally a tiny shell of 1 to several hundred nanometers.The wall alkali shell film of this shell, the protective film) is usually a continuous and strong film (its thickness is a fraction of a nanometer to a few nanometers. Microencapsulation is an important modification method for preparing inorganic-organic composite colloidal particles.


3. Other surface modification methods


High-energy modification: surface treatment using ultraviolet, infrared, corona discharge and plasma irradiation. However, high-energy modification is rarely used for the modification of industrial BaSO4 due to its complex technology and high cost. Acid-base treatment is also a surface auxiliary treatment method. The acid-base treatment can improve the adsorption and reaction activity of the powder surface (or boundary two. In addition, there are methods such as chemical vapor deposition (CV D) and physical vapor deposition of pepper PV D).


4. Chemical deposition method.


It mainly uses precipitation reaction to add modifier or precipitant, and at appropriate pH and temperature, the inorganic modifier is uniformly precipitated in the form of hydroxide or hydrated oxide, forming a layer (or multiple islands) on the BaSO4 surface. The coating layer is then washed, dehydrated, dried, roasted, etc. The coating layer is firmly fixed on the surface of BaSO4, so as to achieve the purpose of surface modification of BaSO4 powder. Another method is to change the molecular weight from several hundred to Thousands of oligomer crosslinking agents or catalysts are dissolved or dispersed in a certain solvent, and then BaSO4 ultrafine powder is added, stirred and heated for a certain period of time to obtain the surface coating of the filler.