Nihon Reoroji Gakkaishi
Online ISSN : 2186-4586
Print ISSN : 0387-1533
ISSN-L : 0387-1533
Rheology of Colloidal Suspensions Flocculated by Polymer Bridging
Yasufumi OTSUBO
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JOURNAL FREE ACCESS

1993 Volume 21 Issue 4 Pages 227-232

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Abstract

When a high-molecular-weight polymer chain adsorbs onto more than two particles and causes flocculation in colloidal suspensions, the effect is referred to as bridging flocculation. The suspensions flocculated by polymer bridging show unique rheological behavior due to long-range interaction and flexibility of bridges. The mechanisms of unique rheological behavior are discussed in relation to the bridging conformation.
The suspensions respond elastically to small deformation when both the particle and polymer concentrations are increased above some critical levels. Although the elasticity arises only from the attractive forces between particles, the three-dimensional network structure must be developed over the system for elastic responses of suspensions. The network formation process is analyzed on the basis of site-bond percolation. Scaling arguments enable us to show a power law dependence of elasticity on the difference of probability from the critical value. For site percolation process, the critical site probability and scaling exponent are independent of bridging conformation. However, the scaling analysis is not applicable to the bond process, because a collection of particles connected by one polymer chain may behave as a unit floc and a series of bridges in the floc cannot be broken to non-interacting bonds.

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© The Society of Rheology, Japan
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