Influence of melt-down ratio and composition on drop coalescence in PA6/HDPE blends

The deformation of polyamide-6 drops in high density polyethylene at different compositions and melt-drawn ratio was studied. The mixtures were prepared using a twin-screw extruder with a rectangular slit at 250 °C. The rectangular sheets were cooled in water and then taken up on a roll. The extrusion velocity was maintained constant at 100 cm/min. The take up velocity was varied in order to obtain different states of deformation of the minor phase. The morphology results show that at low take up velocity the final state deformation is independent on the dispersed phase composition. However, at high take up velocity the drop deformation increases with the composition. This result may be explained in terms of the coalescence phenomena. In the determination of average particle volume of the dispersed phase as a function of the drawn ratio, it was observed that the coalescence effects becomes important at concentration higher than 5% volume of PA6