Microstructure of polymer-clay nanocomposites studied by positrons

The epoxy-rectorite nanocomposites with different rectorite contents, epoxide equivalent were prepared and its microstructure was studied by positron annihilation and X-ray diffraction (XRD). At low rectorite content (0-2.0%), the free volume size in nanocomposites is nearly the same, but its concentration decreases with increasing content; the exfoliated structure was observed by XRD and interfacial layer formation between rectorite platelets and epoxy matrix was probed by positrons. Comparing with epoxy-montmorillonite, the exfoliated structure and interfacial layers are easier formed in epoxy-rectorite nanocomposites.