Supercritical CO 2 as an exfoliating aid for nanocomposite preparation: Comparison of different processing methodologies

This article examines several new methods for compounding nanocomposite materials by twin screw extrusion that use supercritical CO 2 as a processing aid to produce more highly exfoliated polyolefin‐layered silicate nanocomposites than conventional melt intercalation. These methods varied the manner in which the plasticizing behavior of CO 2 influences the surfactant of an organoclay, the compatibilizer, and the matrix during preparation of a polyolefin nanocomposite. The results have shown that targeting CO 2 to the organoclay‐compatibilizer interface can improve the extent of intercalation. However, reduced performance was observed when CO 2 was introduced predominantly to the matrix or neat organoclay. In general, the different techniques of addition for CO 2 did bring about greater structural changes to the organoclay, but the stiffness of the resulting materials was lower than simply following a conventional melt intercalation approach. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers