ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Bueche and Harding [J. Polymer Sci. 32 177 (1958)] obtained an empirical “standard flow curve” to relate viscosity and shear rate by using a particular poly(styrene) solution and positioning the flow curve on a dimensionless rate of shear axis via the viscosity average molecular weight, MV and Bueche's expression for the relation time, τ, where \documentclass{article}\pagestyle{empty}\begin{document}$$ \tau = 12\eta _{\rm o} {\rm M}_{\rm R} /\pi ^2 {\rm RTC} $$\end{document} Here R is the gas constant, ηo is the low rate of shear Newtonian viscosity, T is the absolute temperature, C is the Concentration in grams per cubic centimeter, and MR is te molecular weight which determines the relaxation time. Bueche implies by his standard curve that MV correlates with MR. In Gereral, it was found that: 1) MR does not equal MV but it is usually significantly lower than MV or MW; (2) the value of MR increases with increasing polymer concentration and temperature; and (3) the shapes of the flow curves are slightly different from the shape of the standard curve. A survey of the data available in the lon the flow of polymer melts supports these conclusions. Thus, the Bueche-Harding method can only give semi-quantitative help I predicting the flow behavior of polymeric melts.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760040408
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