The viscosities of the five polymers (PS, PMMA, PC, HDPE, and PP) chosen for melt blending were measured over a wide range of temperatures at shear rates ranging from 0.001 to 1000 s.

People conducted a ‘screw pullout’ experiment to investigate the evolution of blend morphology, determined by transmission or scanning electron microscopy, along the extruder axis. People found that the initial blend morphology depends very much on the difference in Tcf or Tm between the constituent components and, also, on the viscosities of the constituent components. People observed that a co-continuous morphology was formed at the front end of the extruder, which then transformed into a dispersed morphology towards the end of the extruder. People found that the blend ratio determined the state of dispersion for asymmetric blend compositions and the viscosity ratio determined the state of dispersion for the symmetric blend composition.