Nanostructuration of Polyamide 6/Polyetheramines Blends by Reactive Extrusion: Reducing Viscosity While Improving the Tensile Properties

Nanostructurated polyamide-based blends were synthesized by reactive extrusion with multifunctional amine-terminated polyethers in a twin-screw extruder. All the reactive blends exhibited a noticeable reduction of the viscosity (up to 50%), while only the systems synthesized with a small amount of the trifunctional Jeffamine T-403 (0.7 wt %) depicted an increase of the Young's modulus and yield strength by 20 and 13%, respectively, compared to the neat polyamide. The amorphous phase mobility and tensile properties modifications were explained by the crystalline nanostructure evolution of the chemically modified polyamide 6 (PA6). For the smallest quantity of amine, chains mobility evolutions in the amorphous phase of the blends PA6/T-403 were associated with the mobile amorphous fraction/rigid amorphous fraction (RAF) ratio. The material stiffening was not only due to a higher RAF content but also due to thicker crystalline lamellae. On the contrary, a difunctional diamide, Jeffamine D-400, led to chain scissions with no modification of the RAF content.