Experimental study of melting of polymer blends in a starve fed single screw extruder. Issue 12 (4th June 2016)

• Record Type: Journal Article
• Authors: Wilczyński, Krzysztof J.; Lewandowski, Adrian; Wilczyński, Krzysztof
• Is Part Of: Polymer engineering & science. Volume 56:Issue 12(2016:Dec.)
• Page Start: 1349
• Page End: 1356
• Publication Date: 2016-06-04
• Subjects: Polymer engineering -- Periodicals; Polymers -- Periodicals; 668.9
• DOI: 10.1002/pen.24368
• Languages: English
• ISSNs: 0032-3888

Abstract

Abstract : Experimental study is presented of the melting mechanism of polymer blends in a starve fed single screw extruder. Various polyblends were investigated such as PP/PS, HDPE/PS, and PP/PMMA. "Screw pulling‐out" technique was used to study the solid conveying, melting mechanism, and extent of starvation. It has been concluded that melting mechanism consists of two stages: conductive melting in the starve fed region and dispersed melting in the fully filled region. Substantial differences between melting of neat polymers and polymer blends were observed. In the case of polyblends, in the starved region a mixture of two solid polymers is melted by conduction, and in the fully filled region a dispersion of one or two solid polymers in a molten matrix is observed. Although contiguous solids melting mechanism was not seen for starve fed extrusion of polyblends, it was clearly observed for flood fed extrusion. Melting action seems to be faster for starve fed extruders than for flood fed machines, since the polyblend granules are not compacted into a dense solid bed. It was observed the pressure considerably decreases with level of starvation. Filling of the screw increases with an increase of the feed rate of polyblend, and decreases with an increase of the screw speed. Global modeling of the starve fed single screw extrusion of polyblends has been discussed. POLYM. ENG. SCI., 56:1349–1356, 2016. © 2016 Society of Plastics Engineers