Dc. Erickson et al., High-shear-rate behavior of radial hydrogenated styrene-isoprene and blockethylene-propylene copolymer solutions, IND ENG RES, 40(16), 2001, pp. 3523-3529
Using a capillary viscometry technique, the high-shear-rate behavior of two
polymer additives (an ethylene-propylene block copolymer and a radial hydr
ogenated styrene-isoprene copolymer) in a hydrocarbon-based oil solution ha
s been investigated. At mass concentrations of up to 2.0% for the styrene-i
soprene copolymer and 1.5% for the ethylene-propylene additive, the viscosi
ty was measured over a range of shear rates from 10(4) to 10(6) s(-1). To c
orrect for the effects of viscous heating and pressure changes, a numerical
correction procedure is used which reduces the experimental results to vis
cosity data at a common reference temperature and pressure tor comparison.
Over the range of shear rates examined, the styrene-isoprene solutions exhi
bited typical shear-thinning behavior, becoming more dramatic at higher pol
ymer concentrations. In addition to shear thinning at the higher shear rate
s, a shear-thickening region was observed in the more concentrated ethylene
-propylene solutions. As the polymer concentration increased, the degree of
shear thickening was shown to be more severe and the critical region was o
bserved at lower shear rates.