Analysis of the application of carbon black in plastics

1. Basic properties of carbon black The basic properties of carbon black, primary particle size, structure, porosity and surface functional groups have the following effects on plastic properties:

1.1 Carbon black has a small primary particle size (large specific surface area) (1) can increase the blackness of carbon black; (2) can increase the coloring power of carbon black; (3) can enhance the ability of carbon black to resist ultraviolet rays; (4) can Improve the conductivity of carbon black; (5) increase the viscosity of plastics; (6) reduce the dispersion of carbon black; (7) increase the water absorption of carbon black and plastic. The water absorption of carbon black has a great relationship with the nitrogen adsorption specific surface area of ​​carbon black. When mixed with a resin to form a plastic, the primary particle size of the carbon black will be a major factor affecting the amount of water absorbed by the plastic.

1.2 The high carbon black structure (1) will reduce the blackness and tinting strength of carbon black; (2) can improve the dispersibility of carbon black; (3) can increase the viscosity of plastic; (4) increase the conductivity of carbon black; (5) In the use of conductive carbon black, the amount of carbon black used can be reduced. The carbon black structure is a representation of the degree of carbon black chain or the size of the carbon black aggregate. The carbon black structure is divided into a primary structure, or a primary structure and a secondary structure. The primary structure refers to the structure formed by the primary aggregates. The primary structure is relatively firm and not easily destroyed, so the primary structure is the structure actually existing in the plastic system. The secondary structure is an agglomerate formed by the aggregation of carbon black aggregates by van der Waals force. The secondary structure is not strong and is easily damaged during the processing of plastics. The pore volume of carbon black is directly related to the structure. The carbon black with high structure has a large pore volume; the carbon black with low structure has a small pore volume, so the pore volume is a measure of carbon black structure. Generally, the pore volume of carbon black is determined by a liquid absorption method and a compression specific volume method. The pore volume of carbon black affects the "weight" of carbon black of a certain particle size to some extent. Therefore, adding carbon black of the same weight but with a large pore volume can increase the volume of carbon black particles in the plastic, and also increase the volume. The electrical conductivity of plastic products.