Polyamide 6 (PA6)/HDPE/organo-bentonite (Oclay) and PA6/HDPE-grafted-acrylic acid (PEAA)/Oclay nanocomposites were prepared via melt compounding. The influence of Oclay on the morphology of composites was investigated. Scanning electron microscopy results revealed the size of the dispersed HDPE, and PEAA phase decreased with increasing Oclay content. Transmission electron microscopy and X-ray diffraction results revealed that the Oclay was predominately intercalated with some evidence of partial exfoliation. The majority of Oclay platelets were concentrated in the PA6 phase and in the interfacial region between PA6 and HDPE (PEAA). The Oclay platelets played the role of coupling species between the two polymers, increasing the interaction of the two phases in certain extent. These results were proved by FTIR and positron annihilation lifetime spectroscopy. Consequently, apparent emulsifying effect was induced. A schematic mechanism of the apparent compatibilization effect was presented. POLYM. ENG. SCI., 47:551–559, 2007. © 2007 Society of Plastics Engineers.