Abstract
The gel quantity of rubber loaded with calcium carbonate differs according to the kind of calcium carbonate as well as the kind of rubber.
When the rubber is loaded with carbon black, the gel quantity corresponds to the specific surface area. Similar tendency can be seen in the rubber loaded with calcium carbonate, but its gel developing mechanism and its properties are still unknown and seem to be quite different from carbon-gel.
For example, the gel quantity of calcium carbonate formed with the straight chain of ultra fine primary particles is not influenced by the degree of milling, even though its structure may extremely resemble carbon black.
Chain combinations of ultra fine calcium carbonates are very weak and easily broken to primary particles when mixed in rubber. These calcium carbonates improve reinforcement of vulcanized rubber because of their dispersed fine particles.
And, properties of gel gained from the rubber compounded with calcium carbonate or FT black vary depending on the presence of accelerator or coagent.
