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Rheological behavior of two‐phase polymer melts
Author(s) -
Han C. D.,
Yu T. C.
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.760120203
Subject(s) - die swell , materials science , rheology , polystyrene , polymer , phase (matter) , composite material , capillary action , rheometer , microstructure , polyethylene , dispersion (optics) , extrusion , optics , chemistry , physics , organic chemistry
Rheological behavior of dispersed two‐phase polymer melts has been investigated by means of a capillary rheometer. The two‐phase systems chosen for study were blends of two polymers: high‐density polyethylene and polystyrene, which are incompatible in the molten state. In order to investigate the state of dispersion, photographs were taken of the microstructure of extrudate samples, showing that the polystyrene forms long fibers or droplets as a discrete phase dispersed in the polyethylene which forms a continuous phase. Measurements were made of the axial pressure distributions of the two‐phase molten polymers flowing through circular tubes, which permit one, according to the theory advanced by Han, to determine viscous and elastic properties of the melts. Also measured was melt die swell ratio. It has been found from the two independent experimental techniques that there exist a maximum and/or minimum elastic property at a certain blending ratio, and that the elastic property decreases first with L/D ratio of a capillary and then levels off.