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On the non‐newtonian viscous behavior of polymer melts in terms of temperature and pressure‐dependent hole fraction
Author(s) -
Dinc Fatma Sahin,
Sedlacek Tomas,
Tav Cumali,
Yahsi Ugur
Publication year - 2014
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.40540
Subject(s) - polymer , thermodynamics , materials science , fraction (chemistry) , newtonian fluid , non newtonian fluid , polymer chemistry , polymer science , chemistry , composite material , physics , organic chemistry
ABSTRACT A new theoretical non‐Newtonian viscosity model is developed by taking the fractional series expansion of Eyring's shearing strain rate. A broad range of experimental rheological data of various polymer melts including polyethylenes, polypropylene, polystyrene, poly (methyl methacrylate), and polycarbonate are fitted well using the proposed model. From the model; zero shear, constant shear‐stress and constant shear‐rate viscosities are derived as a linear function of viscosity related quantity, Y h , called “thermo‐occupancy function” and their coefficients are discussed in detail. The thermo‐occupancy function is expressed in terms of temperature and structural vacancies such as hole fraction computed from the Simha‐Somcynsky Hole Theory (SS). In addition, the derivative of the logarithm of viscosities with respect to the hole fraction, named as viscoholibility, is observed decreases with the increasing hole fraction. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40540.