Capillary extrusion of polypropylene/high-density polyethylene immiscible blends as studied by rheo-particle image velocimetry

摘要: Abstract The capillary extrusion of polypropylene (PP) and high-density polyethylene (HDPE) immiscible blends was studied in this work by rheo-particle image velocimetry (Rheo-PIV). PP/HDPE were prepared single screw extruded through a transparent die at temperature 200 °C concentrations 80/20, 60/40, 40/60 20/80 wt%, respectively. PIV measurements described accurately the flow behavior revealed continuous velocity profiles die, without macroscopic phase separation, for all resolution range technique. shear-thinning (power-law) type their viscosities laid between values corresponding to neat polymers increased an exponential way along with concentration highest viscosity component blend (HDPE). Also, it found that acquired stratified morphology HDPE mitigates extrudate distortions PP, meanwhile PP eliminates slip instabilities migrating region shear stresses die. Migration wall corroborated Raman spectroscopy on periphery solid extrudates. Finally, via calculations density molten under using we show homopolymers are compatible state follow simple inverse relation density, one viscosity.