Premium
Melt flow instabilities in capillary flow of two‐phase polymer systems
Author(s) -
Han C. D.,
Lamonte R. R.
Publication year - 1972
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.760120202
Subject(s) - materials science , die swell , polystyrene , extrusion , polymer , composite material , high density polyethylene , shear rate , capillary action , shear (geology) , shear stress , shear flow , polyethylene , pellets , thermodynamics , viscosity , physics
An experimental study was made of melt flow instabilities in extrusion of two‐phase polymer systems. For the study, blends were prepared from two polymers: polystyrene (Dow Chemical STYRON 686) and high density polyethylene (Union Carbide DMDJ 4309). The experimental technique used in the present study was the same as that described in a previous paper by the authors. The study shows that there are abrupt increases both in exit pressure and in the recoverable shear strain (defined as the ratio of the exit pressure to shear stress) at the critical flow conditions. It has also been found that an addition of a small amount of high density polythylene (2.5 wt‐% and 5.0 wt‐%) increases the critical shear rate of polystyrene and hence results in a higher throughput rate before extrudate distortion is actually observed. This result is explained in terms of the independently determined melt elasticity of the two‐phase systems investigated.