Influence of Miscibility on Viscoelasticity, Structure, and Intercalation of Oligo-poly(caprolactone)/Layered Silicate Nanocomposites

Nanocomposites of oligo-poly(caprolactone) (o-PCL) with layered silicates having a variety of organic modifiers have been prepared by simple mechanical mixing. The effect of organic modifier type on the miscibility with o-PCL has been studied. The results indicate that miscibility increases with increasing alkyl chain length in the silicate modifier. All possible dispersion states (immiscible, intercalated, and exfoliated) were observed in the o-PCL nanocomposites produced in this study, based on different kinds of organic modifiers and various aspect ratios of the layered silicates. Viscoelastic properties strongly depend on the miscibility factor in the same way as the nanostructure of a nanocomposite determines the ultimate properties. Observed non-Newtonian behavior of a highly miscible nanocomposite was explained by the formation of network structure under a force field. The nature and extent of intercalation of the oligomer strongly depend on the nature of the interactions between the oligomer and the organically modified silicate. The intercalation mechanism has been given on the basis of the observed results, with the experimental results corresponding well with thermodynamic considerations.