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Analysis of void formation in extruded bars
Author(s) -
Titomanlio G.,
Piccarolo S.,
Marrucci G.
Publication year - 1985
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.760250206
Subject(s) - materials science , extrusion , void (composites) , composite material , bar (unit) , viscosity , mechanics , physics , meteorology
Abstract In extruding thick polymeric objects such as bars, voids may form as a consequence of fast cooling. As is well known, this phenomenon is due to volume contraction of the inner zone which takes place when the external “shell” is already solidified. Recent experimental results on this effect show the influence of various parameters such as polymer melt viscosity, bar diameter, and operating pressure upon a critical extrusion velocity above which voids are detected. A detailed analysis of the phenomena which are thought to be relevant is presented and compared with the experimental results.