ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
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:
Dilute solution of a styrene-hydrogenated butadiene copolymer, a viscosity index improver, were studied by static and dynamic light-scattering techniques. In n-hexane (a model solvent for paraffinic oils) and a mineral base oil, aggregation is observed below 30°C. In cyclohexane (a model solvent for napthenic oils) only isolated polymers are present in the whole temperature range.Kinematic viscometric measurements from 20 to 60°C in the mineral oil show a continuous increase of the intrinsic viscosity together with a decrease of kH, the Huggins coefficient, from 2.5 to 0.5. At shear rates between 5000 and 40000s-1, a large shear thinning is observed at room temperature for the polymer in the mineral base oil. This effect progressively disappears as the temperature increases and the suspension becomes Newtonian near 100°C. All results can be interpreted in terms of micelle formation. © 1994 John Wiley & Sons, Inc.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1994.070511004
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