Sol/gel phase diagrams of industrial organo-bentones in organic media

The gelation process of industrial organo-bentone in organic solvents is a complex phenomenon due to various parameters, such as, the crystallographic nature of the clay, the nature of adsorbed surfactant, the dielectric constant of medium. Sol-gel phase diagrams have been established by varying the dielectric constant versus solid-liquid ratio of the mixture (mass percentage). To modify the dielectric constant, different polar agents, such as, alcohols are added to organo-clay suspensions dispersed in non polar organic solvent. With trioctahedral clays, we showed that the alkyl chain length of alcohols has a relevant influence on gelation. Addition of short alkyl chain alcohols increases the gelation ability, whereas, the addition of long alkyl chain alcohols delays the gel formation. In the case of these trioctahedral clays, gelation process was explained by a polarisability change of the organo-clay particles and of the solvent molecules. The influence of water has also been investigated because the polar agents used contain small amounts of water (< 2%). With dioctahedral clays, we showed that the alkyl chain length of alcohols had no influence on gelation.