Viscoelastic and Morphological Study of Polyamide-6/Polyethylene/SEBS-g-DEM Ternary Blends

The viscoelastic and morphological properties of ternary reactive blends of different low and linear low density polyethylenes, polyamide-6 and functionalized SEBS were studied. The SEBS was functionalized via reactive extrusion using diethylmaleate as the functionalizing monomer. Even though the grafting degree achieved was very low (about 0.040 wt%) due to the high melt viscosity of the SEBS, a lower particle size and no coalescence of the dispersed phase were obtained when SEBS-g-DEM was added to the blends and when the polyamide was the dispersed phase. There was no change in the dispersed phase size when the SEBS-g-DEM was used between 3 to 5%. However, when 10% was added, there was an increase in the volume average diameter due to the excess of emulsifier agent that builds up an additional dispersed phase. In addition to the viscosity ratio, the influence of the elasticity on the dispersed phase size is important and should be considered. When LLDPE and LDPE2 with similar viscosity curves were used as minor components, a finer dispersed phase was obtained with LLDPE which showed lower G1 values.