Effects of solvent solubility parameters on organoclay dispersions

With Hansen's solubility parameters, delta(o)(2) = delta(d)(2) + delta(p)(2) + delta(h)(2), the correlation between the degree of exfoliation of organically modified clays and the solvent in which the clay platelets are dispersed/mixed has been analyzed. It has been found that the dispersion force of the solvent, reflected by delta(d), is the principal factor determining whether the clay platelets remain suspended in the solvent while the polar (delta(p)) and hydrogen-bonding (delta(h)) forces affect primarily the tactoid formation/structure of the suspended platelets. The organically modified clays studied in this work precipitated in any solvent with molecules with moderately strong hydrogen-bonding groups. The correlation found has been used to correctly identify a solvent, trichloroethylene, which completely exfoliates the organically modified clay studied in this work.