The conductivity of conductive PP plastic is obtained by the conductive filler particles in the plastic connected to each other to form a conductive path. When the carbon black content is low, the conductivity is small. With the increase of carbon black content, the contact between particles increases, the probability of forming a network increases, and the conductivity increases. What are the factors that affect the performance of conductive PP plastics?
After selecting a carbon black, the structure, morphology and conductivity of the polymers used are also different. After the formulation of conductive PP plastic is determined, the choice of blending method and process control is the key to affect electrical performance.
The twin-screw granulation adopts forced cutting. Due to the large content of carbon black, large volume, uneven cutting, and sometimes local carbon black is too much, making cutting difficult or even blocking the discharge holes. These phenomena cause uneven conductivity To this end, repeated granulation is very effective to improve the melt index of the mixture.
The open mill roll blending facilitates the mixing of more carbon black into the formulation. It should be noted that the number and time of rolling should be controlled by this method, otherwise the carbon black structure will be damaged and its conductivity will be affected.
In the preparation process, the primary spherical particles of carbon black agglomerate with each other to form secondary chain aggregates of different sizes, which is called the structure of carbon black. The more chain aggregates, the higher the structure is called.
Moisture is generally adsorbed on the surface of carbon black particles, and its content is related to the surface properties of carbon black. The larger the specific surface area of carbon black and the higher the oxygen content, the greater the amount of water adsorption. Although the presence of moisture is conducive to improving the conductivity, it usually makes the conductivity unstable, so it should be strictly controlled. The performance of conductive PP plastics may be affected by the above factors.