Tensile and fatigue behavior in clay reinforced nylon 6 nanocomposites

Abstract

It is shown that 2 wt% clay-reinforced nylon and 4 wt% clay-reinforced nylon have similar tensile strengths, which are increased by about 30% compared to those of nylon 6. With an increase in loading rate, the ultimate tensile strength increases for both nylon 6 and nanocomposites, and the ductility decreases for nylon 6 while it does not change obviously or even increase a little for nanocomposites. The fatigue strength of 2 wt% clay-reinforced nylon is also increased by about 30% compared to that of nylon 6, but the fatigue strength of 4 wt% clay-reinforced nylon is slightly increased or similar to that of nylon 6. The cyclic deformation has been examined using stress-strain hysteresis loops. The small cyclic deformation in 4 wt% clay-reinforced nylon is attributed to the no increase in fatigue strength. The strain incompatibility near the phase boundary leads to the relaxation of three dimensional stress field in 2 wt% nano-composite, while leads to the extraction of clay platelets in 4 wt% nano-composite. Furthermore, timedependent behavior and microscopic damage mechanisms are discussed. © 2009 The Society of Materials Science.