The mechanical and thermomechanical properties as well as microstructures of polypropylene/nylon 6/clay nanocomposites prepared by varying the loading of PP-MA compatibilizer and organoclay (OMMT) were investigated. The compatibilizer PP-MA was used to improve the adhesion between the phases of polymers and the dispersion of OMMT in polymer matrix. Improvement of interfacial adhesion between the PP and PA6 phases occurred after the addition of PP-MA as confirmed by SEM micrographs. Moreover, as shown by the DSC thermograms and XRD results, the degree of crystallinity of PA6 decreased in the presence of PP-MA. The presence of OMMT increased the tensile modulus as a function of OMMT loading due to the good dispersion of OMMT in the matrix. The insertion of polymer chains between clay platelets was verified by both XRD and TEM techniques. The viscosity of the nanocomposites decreased as PP-MA loading increased due to the change in sizes of PA6 dispersed phase, and the viscosity increased as OMMT loading increased due to the interaction between the clay platelets and polymer chains. The clay platelets were located at the interface between PP and PA6 as confirmed by both SEM and TEM. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 538-546, 2010