Abstract: A non-intermeshing twin-screw element was designed based on the elongational flow in the polymer processing. The mixing performance of the element was compared with that of S type screw element. Cumulated maximum tensile rate distribution and differential pressure between exit and entrance were obtained by simulation for flow field of non-intermeshing elongational element and S type screw element. Moreover, the influence of non-intermeshing elongational element and S type screw element on the phase morphology incompatible polymer blends PP/PS was compared. It was found that the conveying performance of non-intermeshing elongational element was worse, but the elongational and dispersive mixing performances were better than those of S type screw element.

Key words: intermeshing co-rotating twin-screw extruder, dispersive mixing, elongational flow, screw element