Melt viscosity of oligomeric triblock copolymers (type PEP) of ethylene and propylene oxides

Melt viscosity η at 25°C of four oligomeric triblock copolymers consisting of a central block of ethoxamer units and two end blocks of propoxamer units (PEP) (Mn × 10−3 = 1 and 2; mole fraction of ethoxamer units xE = 0.41, 0.57, and 0.74) was analyzed in terms of the theory advanced by Berry and Fo...

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Bibliographic Details
Published in:Journal of applied polymer science 1994-06, Vol.52 (13), p.1905-1912
Main Authors: SIMEK, L, PETRIK, S, BOHDANECKY, M
Format: Article
Language:English
Subjects:
Applied sciences
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Properties and characterization
Rheology and viscoelasticity
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Summary:Melt viscosity η at 25°C of four oligomeric triblock copolymers consisting of a central block of ethoxamer units and two end blocks of propoxamer units (PEP) (Mn × 10−3 = 1 and 2; mole fraction of ethoxamer units xE = 0.41, 0.57, and 0.74) was analyzed in terms of the theory advanced by Berry and Fox. The structure‐dependent factor F(X) was deduced from the intrinsic viscosity data, and the mean friction factor per friction center ζ was computed from η and F(X). At a fixed molecular weight, it increases with increasing xE. The dependence of ζ versus xE was compared with curves computed from the data for homopolymers. The best agreement was obtained if the following values of the inherent friction factor (log ζ0) were used: −10.25 for poly(ethylene oxide) PEO and −10.65 for PPO. © 1994 John Wiley & Sons, Inc.
ISSN:0021-8995
1097-4628
DOI:10.1002/app.1994.070521307