A technique for improving the exfoliation of organically modified layered silicate (OMLS) in a poly(ethylene terephthalate) (PET) matrix using super critical carbon dioxide (scCO(2)) is compared to traditional direct melt blending. The process relies on the rapid expansion of a scCO(2)/OMLS mixture directly into the second stage of a single screw extruder where the clay and scCO(2) mixture is subsequently melt blended with the PET matrix. The simple, environmentally benign process results in a more highly delaminated system than traditional direct melt compounding. X-ray diffraction analysis is used to reveal improved clay morphologies and the resulting mechanical properties are examined. Rheology is used as a tool to draw conclusions about the effect that scCO(2) has on reducing PET matrix degradation during processing. POLYM. ENG. SCI., 49:2329-2341, 2009. (C) 2009 Society of Plastics Engineers