Location of nanoclay at the interface in immiscible poly-caprolactone / polyethylene oxide (PCL/PEO) blend and its effect on the compatibility of the components

<p>Nanocomposites based on 80/20 and 20/80 (wt:wt) PCL/PEO immiscible blends and organophilic layered silicates were prepared using melt-extrusion. From transmission electron microscopy analysis, it is observed that the exfoliated silicate platelets were preferentially located at the interface between the two blend phases. When the blend-based nanocomposite is prepared via a two-step process by first premixing the silicates with the PEO component or with the PCL component, the silicate layers migrate from the PEO phase or PCL phase to the interface. The rheological behaviour of the nanocomposites was also investigated. At low frequencies, the frequency dependence of the storage modulus changes from a liquid-like behaviour for the unfilled blend to a solid-like behaviour for the nanocomposites, indicating the formation of a network structure as a result of exfoliation. From the scanning electron micrographs, a monotonic decrease of the PEO domain size in the 80/20 PCL/PEO blend was observed as a function of the organophilic clay content. Therefore a clear emulsifying effect was induced by the organophilic layered silicates in the immiscible PCL/PEO blend.</p>