Several effects of carbon black on rubber properties

The greater the chemical activity of carbon black is, the more bound rubber is generated during mixing, which increases the Mooney viscosity of the rubber compound, increases the die expansion rate and semi-finished product shrinkage rate during extrusion, and slows down the extrusion speed. The tensile strength, tear strength and wear resistance of vulcanized rubber are higher.

Relationship between particle size of carbon black and rubber properties

Since the active points of carbon black exist on the surface of carbon black, the smaller the carbon black particles, the larger the specific surface area, and the more active points of carbon black of the same quality, which can better exert the effect of carbon black on rubber. Chemical bonding and physical adsorption, thereby enhancing the reinforcing effect. Therefore, the particle size of carbon black is the second factor that affects the reinforcing properties of carbon black, that is, the breadth factor.

The smaller the particle size of carbon black, the higher the tensile strength, tear strength, tensile stress, wear resistance and hardness of the vulcanizate, the better the flexural crack resistance, and the decrease in resilience and elongation at break. . However, if the particle size is too small, the cohesive force between particles will be large, and it will be easy to agglomerate, which will lead to difficulty in dispersion during kneading, and will reduce the plasticity and the extrusion performance.

The relationship between carbon black structure and rubber properties

The structure of carbon black is the third factor affecting the reinforcing properties of carbon black, that is, the shape factor. This is because carbon black with high structure has complex polymelt morphology, many branches, and large internal voids. When mixed with rubber, more occluded rubber (or inclusive rubber) is formed. Since the carbon black polymer melt can hinder the deformation of the absorbed rubber molecular chain, it has a significant effect on the improvement of the vulcanizate's tensile stress, hardness and other properties, thus reflecting the reinforcing function. At the same time, the formation of occluded rubber also plays a significant role in improving the dispersibility of carbon black during mixing and improving the extruding performance. large and smooth.