Preparation of clay mineral polymer nanocomposites by adsorption in solution

Novel clay mineral polymer nanocomposites (CPN) were prepared by direct addition of a polyesteramide (PEA) solution to organomontmorillonites (OMt). PEA matrices were obtained by the anionic copolymerization of ε-caprolactam (CLA) and ε-caprolactone (CLO) containing 20–100 mol% of CLO units. The matrices were used to test the exfoliation of two OMt (Cloisite 30B and Cloisite 25A). The extent of exfoliation was dependent on the mutual interaction of all three components (polymer, solvent and OMt). The degree of OMt–solvent interaction was assessed from the swelling factor and basal distance, the latter being measured by the WAXS method. The polymer–solvent interaction was determined from the limiting viscosity numbers measured for each solvent used. Several of the copolymer–solvent–OMt combinations resulted in nanocomposites with a fully- or partially-exfoliated structure.