Different production processes of pigment carbon black have different chemical properties on the surface. The true surface area of most carbon blacks is greater than the geometric surface area calculated from particle size. This is due to the presence of many micropores on the surface of carbon black, especially carbon black with a particle size less than 25nm.
According to analysis, groups such as phenol groups, quinone groups, and carboxyl groups can be detected on the surface of carbon black. The concentration of these acidic groups is particularly high on the surface of gas black and oxidation furnace black.
The pyrone structure can be detected in the furnace black and this structure determines the alkaline nature of the furnace black. The volatile content can determine the concentration of surface functional groups and also measure the polarity of carbon black.
In addition, due to the large surface area of carbon black, it is easy to absorb moisture in the volatile environment. Therefore, special attention should be paid to moisture absorption during transportation, storage and use of carbon black.
Most are studies exploring the geometry of contacts between conducting particles.
This theory holds that the greater the carbon black filling amount, the greater the density of the dispersed carbon black particles or carbon black particle aggregates, the smaller the average distance between particles, and the higher the probability of mutual contact. The more conductive paths formed by black particle aggregates.
The greater the polarity of the blend system composed of polymers and carbon black pigment with different polarities, the greater the critical volume fraction of carbon black pigment , which means that the conductivity of the system decreases, because the surface of specialty carbon black contains strong polar groups. The greater the polarity of the matrix, the stronger the effect. At this time, the strength increases, but it hinders the agglomeration of the conductive particles themselves, resulting in poor conductivity.
However, in a blended system composed of multi-component matrix resin and carbon black, due to the different polarities of different matrices, filling carbon black will cause segregation. At this time, the conductive performance depends on the concentration and distribution of carbon black particles in the segregation phase. The state also depends on the proportion of segregation phase polymer.