Carbon nanotubes with different functional groups were prepared and then incorporated into the poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 6 (PPO/PA6) blend via melt blending. The influence of different carbon nanotubes on the morphology and properties of the blend was studied. The results show that addition of pristine CNTs, CNTs-OH, CNTs-NH2 leads to the evolution of the phase structure of PPO/PA6 (mass ratio: 60/40) blend from sea-island to cocontinuous, whereas incorporation of CNTs-COOH does not change the blend morphology due to serious aggregation of the carbon nanotubes. Incorporating different CNTs into PPO/PA6 blend increases the tensile modulus and storage modulus of the blends, whereas decreases slightly the tensile strength. At the same time, the glass transition temperatures (T-g) of PA6 and PPO are enhanced. Delta T-g, the gap between the T-g of PA6 and PPO, decreases with the addition of carbon nanotubes due to the stronger interaction of carbon nanotubes with PA6 than PPO. A similar tendency was found in the storage modulus (G') and complex viscosity (eta*) of the composites. The dispersion state of different carbon nanotubes and their interaction with polymer components are different, which causes the different confinement effect to the macromolecular chains. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 1322-1328, 2010