ISSN:
1435-1536
Keywords:
Zero-shear viscosity
;
shear viscosity
;
non-Newtonian viscosity
;
semi-dilute solution
;
structure-property relationship
;
relaxation time
;
shear stability
;
degradation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The structure-property relationships derived here permit the prediction of both the zero-shear viscosityη 0, as well as the shear rate dependent viscosity $$\eta (\dot y)$$ . Using this molecular modeling it is now possible to predictη over the whole concentration range, independently of the molecular weight, polymer concentration and imposed shear rate. However, the widely accepted concept: dilute — concentrated, is insufficient. Moreover it is necessary to take five distinct states of solution into account if the viscous behavior of polymeric liquids is to be described satisfactorily. For non-homogeneous, semi-dilute (moderately concentrated) solutions the slope in the linear region of the flow curve (η= $$f(\dot y))$$ must be standardized against the overlap parameterc · [η]. As with theη 0-Mω-c-relationship, aη-M ω -c- $$\dot y$$ relationship can now be formulated for the complete range of concentration and molecular weight. Furthermore, it is possible to predict the onset of shear induced degradation of polymeric liquids subjected to a laminar velocity field on the basis of molecular modeling. These theoretically obtained results lead to the previously made ad hoc conclusion (Kulicke, Porter [32]) that, experimentally, it is not possible to detect the second Newtonian region.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01417863
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