In general research, carbon black conduction can be explained by conductive band and tunneling effect. In carbon black filled polymer, electrical conduction is carried out along the particles in contact or separated into small gaps. The internal aggregate average distance is affected by many parameters, including concentration, structure, size and shape of the aggregate, size distribution, mixing effect, temperature, and so on. Carbon black can be divided into several types according to the production method and raw materials. Only a part of the conductive filler is suitable. They must have some basic characteristics, such as large specific surface area, less impurities for capturing electrons, and better crystallinity.
The structure of carbon black is expressed by the degree of aggregation of carbon black particles into a chain or a grape. Carbon black composed of aggregates composed of the size and shape of the aggregates and the number of particles in each aggregate is referred to as high structure carbon black. At present, the commonly used oil absorption value indicates structurality, and the larger the oil absorption value, the higher the structure of the carbon black, and it is easy to form a space network channel, and it is not easy to be destroyed.
If the surface of the carbon black contains a large amount of oxygen functional groups, it will affect the migration of free electrons and thus affect the conductivity. For example, some carbon blacks produced by thermal cracking and channeling methods have poor conductivity, and the surface of the channel black has a large number of active groups, so the two carbon blacks are poor in conductivity.