1. The structure of conductive carbon black can affect the conductive performance of carbon black:
The size of the DBP value represents the level of the carbon black aggregate structure. Generally speaking, when the DBP value is high, the conductive carbon black has a chain-like structure and has better conductivity. The DBP values of various carbon blacks, which are by-products of heavy oil gas production, are very high. However, electron microscopy shows that they have empty shell microstructures, indicating that their structures are not very high. Its high electrical conductivity may be due to its larger volume per unit mass and the shearing that destroys part of the primary structure and produces a large number of new particles.
To obtain good electrical conductivity in plastics, the carbon black must have a larger particle size and the structure should not be too high. It is best to make the carbon black have a linear structure. On the one hand, it can promote the dispersion of carbon black in plastics, on the other hand, it can help form a conductive network, and a small amount of carbon black can achieve antistatic effects.
2. The particle size of conductive carbon black can affect the conductive properties of carbon black:
Theoretically, the smaller the particle size of conductive carbon black, the greater the number of particles per unit volume, which is beneficial to improving conductivity, which is normal in conductive rubber products. However, when used in conductive plastic products, if the carbon black particles are too small, the shear force after the plastic is plasticized is small, so the dispersion is poor. Performance is reduced and practical value is lost.
Therefore, the particle size of conductive carbon black must be controlled within a certain range to ensure that the carbon black can be well dispersed in the plastic, and to greatly increase the number of carbon black particles per unit volume in the plastic, thereby improving the conductive properties of plastic products. , while not damaging or less damaging the original mechanical properties of the product.
3. Surface volatile matter can affect the conductive properties of carbon black:
The volatile matter on the surface of conductive carbon black is mainly composed of some organic groups and an oil film that has not been completely cracked, forming an insulating layer, which increases the potential barrier between carbon black particles and seriously affects the conductivity. The volatile matter must be removed Control within lower limits.
4. The roughness of carbon black can affect the conductive properties of carbon black:
Since conductive carbon black needs to have a certain roughness to conduct electricity, the carbon black can easily form conductive channels, so the difference between the carbon black’s nitrogen adsorption surface area and the CTAB surface area is required to be large.
5. Ash and moisture can affect the conductive properties of carbon black:
The high ash and moisture content in conductive carbon black actually reduces the content of carbon black, which also has a negative impact on conductivity. During production, attention should be paid to controlling the ash and moisture content in carbon black. In contrast, the carbon content of acetylene carbon black is as high as 99.18%, while that of general carbon black is less than 98%. The moisture content should generally be controlled below 2.15%, otherwise a large number of bubbles will be produced, which will affect the mechanical properties of the product.