1. The structure of conductive carbon black can affect the conductivity 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 branch structure, and the conductivity is better. The DBP values of various by-products of heavy oil and gas-making carbon black are very high, and the electron microscope finds that they have an empty shell microstructure, which shows that their structure is not very high. Its high conductivity may be due to its larger volume per unit mass, and the second is that shearing destroys part of the primary structure and produces a large number of new particles. In order to obtain good electrical conductivity in plastics, carbon black must have a larger particle size, and the structure should not be too high. It is best to make the structure of carbon black into a linear structure. On the one hand, it can promote the dispersion of carbon black in plastics, on the other hand, it is beneficial to form a conductive network, and a small amount of carbon black can achieve antistatic effect.
2. The particle size of conductive carbon black can affect the conductivity of carbon black:
Theoretically, the smaller the particle size of conductive carbon black, the more particles per unit volume, which is conducive 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 dispersion will be poor due to the small shear force after the plastic is plasticized. The performance is reduced and the practical value is lost. Therefore, the particle size of conductive carbon black must be controlled within a certain range to ensure that carbon black can be well dispersed in plastics, and can greatly increase the number of carbon black particles per unit volume in plastics, improving the electrical conductivity of plastic products. , while not destroying or less damaging the original mechanical properties of the product.
3. Surface volatile matter can affect the conductivity of carbon black:
The volatile matter on the surface of conductive carbon black is mainly composed of some organic groups and the 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. Control it to a minimum.
4. The roughness of carbon black can affect the electrical conductivity of carbon black:
Since the conduction of conductive carbon black requires a certain roughness, so that the carbon black is easy to form a conductive channel, so the difference between the nitrogen adsorption surface area and the CTAB surface area of the carbon black is required to be large.
5. Ash and moisture can affect the conductivity of carbon black:
The high content of ash and moisture in conductive carbon black actually reduces the content of carbon black, which also has an adverse effect on conductivity. In production, attention should be paid to controlling the content of ash and moisture 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 air bubbles will be generated, which will affect the mechanical properties of the product.
The above five aspects are the main factors affecting the conductivity of carbon black. If you want to buy conductive carbon black with good conductivity, you must pay attention to these five factors.