Chemistry Reference
In-Depth Information
aggregates and the stress to break up into CB aggregates must be almost the same
for the furnace black samples.
Finally, we mention briefly the reasons why the
y
values of the AcB
suspensions are larger than those of CB-76, CB-24-1, and CB-15-2 suspensions.
The surface of AcB develops a graphite structure, although that of the furnace
black does not. The surface structure difference may be attributed to different PS
adsorption behavior and the
eff
dependence of the
y
values, although we cannot
explain the mechanism yet.
Figure 18. Yield stress
y
versus effective volume fraction
eff
for the CB-76/(PS/DBP),
CB-24-1/(PS/DBP), CB15-2/(PS/DBP), and AcB/(PS/DBP) suspensions. a
0
100 nm [32].
4.5. Summary
Steady-shear viscosity of CB/(PS/DB) suspensions are reported as a function
of volume fraction () of various kinds of CB aggregates. The effects of the
primary particle size and the structure of CB aggregates on the rheological
properties are clarified. The suspensions show a typical shear-thinning behavior in
the range of a shear rate studied. The Casson model can be applied to evaluate the
viscosity at infinite of shear rate
and the yield stress
y
for the suspensions.
Relative viscosity
/
m
, (
m
: medium viscosity) thus obtained are compared to
the high-frequency viscosity for the ideal hard-sphere silica suspensions to
