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Experimental study of melting of polymer blends in a starve fed single screw extruder
Author(s) -
Wilczyński Krzysztof J.,
Lewandowski Adrian,
Wilczyński Krzysztof
Publication year - 2016
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.24368
Subject(s) - materials science , plastics extrusion , extrusion , composite material , polymer , polymer blend , melting temperature , melting point , high density polyethylene , polyethylene , copolymer
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