Organic-Silane Coupling Agent for Thermosets, Thermoplastics, and Rubber

They showed the reduction of the viscosity of the cal cite/stearic acid compounds was greater than the talc/stearic acid compound. The existence of stearic acid on calcite particles would appear to emulsify individual calcite particles more effectively than the talc particles and result in greater reductions of the viscosity (Fig. 7.1). 

Stearic acid is often used in the rubber industry in carbon black compounds as a vulcanization activator (e.g., [ 12 ]). When a carboxylic acid is mixed into a rubber compound, it melts and is rapidly incorporated into the compound but usually does not dissolve. This depends on the type of rubber. If stearic acid is insoluble, it can act as a processing aid. In this case it often locates between the surface of the compound and the steel surface of the processing machine. This produces a very low viscosity layer. These carboxyl acids also may act as mold-release agents for cured rubber carbon black vulcanizates or thermoplastics from a metal mold. 

When stearic acid and zinc oxide are mixed into a polymer compound, a reaction may take place between the two materials, which produces zinc stearate and water. 

Plueddemann et al. [ 20 ] introduced the term coupling agent , which characterizes its function in glass fiber reinforced polyester and epoxy laminates in 1962. Later, the applications of alkoxysilylpropyl- type silane coupling agents on particle-fiUed composite systems were applied to thermoplastics [21]. These had the structure 

7 Polymer-Filler-Additives and Curative-Accelerator Compounds 

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Organic-Silane Coupling Agent for Thermosets, Thermoplastics, and Rubber... 

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