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Flow behavior of concentrated solutions of an SBS block copolymer
Author(s) -
Paul D. R.,
St. Lawrence J. E.,
Troell J. H.
Publication year - 1970
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760100204
Subject(s) - viscometer , materials science , copolymer , solvent , shear rate , dispersity , viscosity , polymer , polymer chemistry , capillary action , styrene , thermodynamics , composite material , chemistry , organic chemistry , physics
The non‐Newtonian viscosity of concentrated solutions of a styrene‐butadiene‐styrene, SBS, block copolymer was measured with a novel capillary viscometer. Polymer concentrations ranged from 0.165 to 0.306 g/cc. Apparent shear rates ranged from 1 to 10 5 sec −1 . Five different solvents were employed. All of the flow curves can be reduced to a single master curve with the same shape exhibited by monodisperse polystyrenes and the Graessley theory. The shift factor for the shear rate axis, τ 0 , approximately parallels the Rouse relaxation time, τ R , but shows a residual concentration and solvent dependence not predicted by the Rouse form. For different solvents at the same concentration, better solvents show a minimum relative zero shear viscosity, η 0 /η s , and a maximum ratio τ R /τ 0 . It is concluded that all solvent effects are not adequately incorporated into the zero shear viscosity for the purposes of constructing master plots; however, the shape of the master plot is not affected by the solvent or the polymer block structure.