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Shear‐rate‐dependence modeling of polymer melt viscosity
Author(s) -
Hieber C. A.,
Chiang H. H.
Publication year - 1992
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.760321404
Subject(s) - materials science , shear rate , carreau fluid , polycarbonate , shear (geology) , viscosity , acrylonitrile butadiene styrene , polymer , composite material , copolymer , thermodynamics , mechanics , physics
Steady‐shear‐viscosity data sets for commercial‐grade acrylonitrile‐butadiene‐styrene terpolymer, nylon, polycarbonate, poly(methylmethacrylate), and polystyrence are fitted in terms of a generalized Cross/Carreau modeling for the shear‐rate dependence. Based upon extensive data sets from the open literature as well as in‐house measurements, it is shown that the shear‐rate dependence can be more accurately described in terms of the Cross rather than Carreau model. Although the resulting viscosity fits based upon these two models might differ by 20% or more for the same well‐characterized data set, the resulting effect upon simulating the injection‐molding process is found to be much smaller since such predictions reflect a range of shear stresses (varying linearly from centerline to wall of cavity) over which the two models alternate in relative magnitude. This is demonstrated by detailed representative numerical predictions which are presented for both the filling and post‐filling stages.