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Preparation of nano-scale aqueous carbon black dispersion---sand mill
- Oct 22, 2018 -

Carbon black particles are statistical assemblies of carbon layers. Generally, they are arranged in a concentric graphite layer. They are not highly ordered microcrystals and low-order amorphous materials. Different types of carbon blacks differ only in degree of order. Carbon black is rarely a single, separate spherical particle, usually present as agglomerates of elementary particles that are fused together. Under shear, the aggregates can be redispersed and re-agglomerated.

The structure of carbon black is formed by the fusion of carbon black particles during the production process. As the carbon black particles continue to grow, many of the fused particles join to form a three-dimensional space and chain structure, a structure known as a primary structure or a permanent structure. Its cohesive strength is large and a strong chemical bond is formed between the crystal nucleus. And between the aggregates, the main formation is Van der Waals force, the diameter can be easily destroyed by mechanical shearing force, but the process is also reversible affecting the color and dispersion of carbon black. The smaller the particle size of carbon black, the darker the reflected light, the upper The higher the color intensity.

Effect of grinding time on particle size of carbon black

20 g of carbon black, 5 g of a super dispersing agent and 75 g of deionized water were weighed, and a carbon black high-speed dispersion liquid was prepared according to a carbon black high-speed dispersion preparation method, and a carbon black sanding dispersion liquid was prepared according to the carbon black sanding dispersion liquid method. The experimental results show that with the increase of grinding time, the particle size of carbon black decreases, and the percentage of nano-sized particle size increases obviously. When sanding to 40 min, the particle size of carbon black is 99.6 nm less than 20.9 nm, but it is extended. Time, the particle size increased significantly. The reason may be that as the particle size is further reduced, the surface energy generated by the specific surface area of the particle increases sharply, and after the residual amount of free energy on the surface of the particle accumulates to a certain extent, the particles aggregate to form agglomerates, thereby increasing the particle size.