Why carbon black can strengthen
Adding carbon black when producing rubber will cause cross-linking to form a spatial network structure and wrap carbon black. The surface of carbon black particles forms a structural adsorption layer and rubber macromolecules are adsorbed on the surface of filler ions such as carbon black, resulting in reinforcement with sliding effect. Effect.
Why carbon black has high reinforcing performance
In addition to carbon black, there are many reinforcing fillers in the rubber industry, such as clay, ground calcium carbonate, precipitated silica and fumed silica, among which silica and carbon black have the best reinforcing properties.
As for why silica and carbon black have good reinforcing properties, this is mainly because rubber is an organic substance, mainly composed of C atoms and H atoms, and C in carbon black and Si in silica are in the periodic table of elements They all belong to the same column, and there are 4 electrons outside their nuclei, that is to say, they may be able to participate in any chemical reactions that occur in the process of rubber mixing and vulcanization, and can form bonds with rubber molecules, thereby strengthening rubber molecules. The bonding force between them achieves the effect of reinforcement.
Why carbon black can play a reinforcing role in rubber
The rubber and carbon black form a strong bond that slips. This bond creates a second reinforcing effect. The first reinforcement effect is that when the rubber is deformed by an external force, the slippage of the molecular chain and a large amount of physical adsorption can absorb the impact of the external force, and act as a buffer for the friction or hysteresis deformation caused by the external force; the second effect is Make the stress distribution even. The result of these two effects is an increase in rubber strength. Resisting tearing without too much damage to the elasticity of rubber (that is, the movement of molecular chains) is the basic principle of carbon black reinforcement.
Why does carbon black have no reinforcing effect on plastics?
There is no cross-linking process in the production of plastics, so there is no reinforcing effect, but carbon black treated with surfactants, that is, modified carbon black, can be used to increase the compatibility of carbon black and plastics. Black reinforces plastic.