Fillers in Rubber Industries

The properties of a material that determine its suitability as a filler and the properties it imparts to rubber are its grain-size, surface area of particles and surface activity of particles (i.e. the ability of the particle s surface to bond with the rubber matrix). These properties of clay minerals, especially kaolinite, and their appropriateness as fillers are explained below. 

All cl minerals belong to the phyllosilicate subclass, having thin layers composed of successive tetrahedral and octahedral sheets of atoms and ions. The layers are weakly bonded to one another and thus easily separable to very thin flakes. The platy or flaky nature of the clay particles, thus having large smface areas relative to grain-size, is very much suitable to be used as fillers. 

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