Double yielding in PA6/TPV-MAH blends: Effect of dispersed phase with different content, modulus

In this study, we have investigated the effect of thermoplastic vulcanizates (TPV) content and characteristic on the double yielding of injection molded polyamide 6 (PA6)/TPV blends uniaxially tensile deformed at room temperature. The results indicated that the TPV content and characteristic showed a marked effect on the double yielding phenomenon. The morphological observation by scanning electron microscope (SEM) showed that the injection molded PA6/TPV blends displayed a typical skin-core structure with highly oriented TPV particles in the skin and sub-skin layers, and spherical TPV particles in the core layer. Combining the microscopic morphology and stress-strain behavior, a possible model for description of the double yielding behavior of the PA6/TPV blends was proposed. The first yield point might be caused by the deformation of the matrix and the dispersed phase in the skin and sub-skin layers, while the second yield point is correlated with the deformation of the dispersed phase in the core layer.