Effect of soft segment content of Pebax® Rnew on the properties of Nylon-6/SMA/PEBA blends

To improve the impact property of Nylon 6 at temperature below 0°C, Nylon 6 was toughened by the blending of Pebax® Rnew (PEBA) and compatibilized with poly(styrene-co-maleic anhydride) (SMA). The effect of the content of soft segment of PEBA, polytetramethylene oxide (PTMO), on the toughening properties was investigated. The impact properties of the resulting blends were measured at 23°C and − 20°C. With the increase of PTMO content, the impact strength increased, whereas the tensile and flexural properties decreased. The thermal stability of these blends was not affected significantly. Rheological properties revealed that these blends exhibited predominantly viscous behavior at 240°C. Furthermore, higher PTMO content led to higher storage modulus (G’), lower loss modulus (G”) and complex viscosity (η*). The higher PTMO content of PEBA also improved the toughness more. The DSC results showed that the glass transition temperature (T_g) of Nylon 6 decreased with the increase of PTMO content. The crystallization temperature and the rate of crystallization of the blends were not much affected by the PTMO content, yet the relative amounts of α and γ crystals formed were affected by the type of PEBA added. Based on the Avrami model, the non-isothermal crystallization of Nylon 6 in the blends was a diffusion-controlled crystallization.