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Prediction of the first normal stress difference in polymer solutions
Author(s) -
Meister Bernard J.,
Biggs R. Dale
Publication year - 1969
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690150505
Subject(s) - shear rate , shear stress , shear (geology) , polymer , critical resolved shear stress , thermodynamics , viscosity , stress (linguistics) , shear viscosity , materials science , mechanics , chemistry , physics , composite material , linguistics , philosophy
Shear stress and first normal stress difference data are presented for several polymer solutions undergoing steady shear rates from 1.0 to 100,000 sec. −1 . The steady shear response is divided into three regions as a function of increasing shear rate. These are the diffusion controlled linear region, a moderate shear rate region where shear controls the entanglement‐disentanglement process, and a high shear rate region where aggregation of polymer molecules occurs. The transitions between the three regions are clearly illustrated by using a group designated as the rotation rate function. A molecular model is derived for the shear controlled region that allows prediction of the first normal stress difference from the viscosity function and one additional constant that depends only on the molecular species. The White‐Metzner equation is found to adequately describe the aggregation region at high shear rates.