Processing and microstructure of PCL/clay nanocomposites

The morphology and mechanical properties of polycaprolactone/clay nanocomposite films prepared by two techniques (casting: exfoliation-adsorption; intensive mixing: melt-intercalation) were studied. Casting, which is a laboratory scale technique, was selected because it was supposed that the exfoliation of the layered silicate into single layers would be easier since the solvent acts as an exfoliation agent. The other selected technique was chosen because it can be used in the industry. X-ray diffractograms revealed an intercalated–exfoliated mixed structure for both techniques. For casting, the morphology and mechanical properties are influenced by the used solvent and the preparation conditions being the first one the most critical parameter. Otherwise, in the case of intensive mixing, a higher clay dispersion degree was produced by shear forces and the resultant mechanical properties were superior to those obtained by casting. In both cases, the highest modulus was achieved for 5 wt.% of C30B. Finally, an effective filler-parameters model was used to compare the relative dispersion of clay within the nanocomposites for both processes from the experimental modulus values.