The effect of introducing silver nanoparticles on the rheological properties and dynamic crystallization behavior of nylon-6 was investigated. The nanocomposites showed slightly higher viscosity than pure nylon-6 in the low-frequency range even at an extremely low loading level of the silver particles (0.5-1.0 wt %). The nanoparticles had a more noticeable effect on the storage modulus than on the loss modulus of a nylon-6 melt and reduced its loss tangent. They increased the crystallization temperature of nylon-6 by about 14 degreesC and produced a sharper crystalline peak. The silver nanoparticles promoted the crystallization of nylon-6, and their effect on the dynamic crystallization of nylon-6 at 200 degreesC was more notable at a lower shear rate and at 190 degreesC at a higher frequency. Nylon-6 produced large spherulitic crystals, but the nanocomposites showed a grainy structure. In addition, the silver nanoparticles reduced the fraction of the a-form crystal but increased that of the gamma-form crystal. The nanocomposites crystallized at 190 degreesC showed a lower melting temperature than nylon-6 by about 3 degreesC, whereas the nanocomposites crystallized at 200 degreesC showed almost the same melting temperature. (C) 2004 Wiley Periodicals, Inc.