Full Paper: Phosphate cellulose particles were synthesized via the phosphor
ic ester reaction of cellulose particles, phosphoric acid and urea, with va
rious molar concentrations of the phosphoric acid, and then dispersed in si
licone oil to produce anhydrous dry base electrorheological (ER) fluids. Th
e effect of the phosphoric ester reaction on ER properties was examined und
er various applied electric field strengths. An ER system with phosphate ce
llulose particles formed in a 2.0 M phosphoric acid solution exhibited the
highest yield stress (ER performance) via rheological measurements under bo
th controlled shear rate and shear stress modes. A difference in the flow b
ehavior of the phosphate cellulose-based ER fluids prepared from different
molar concentrations of phosphoric acid solution was also investigated via
the dielectric spectra. It was found that the interfacial polarization mech
anism provides an accurate description of the ER characteristics of phospha
te cellulose-based ER fluids.
[GRAPHICS]
Static yield stress vs. electric field strength measured from the CSS mode
for phosphate cellulose ER fluids-treated with a various phosphoric acid co
ncentrations (particle concentration: 10% (v/v) in silicone oil).