B. Alince et Tgm. Vandeven, KINETICS OF COLLOIDAL PARTICLE DEPOSITION ON PULP FIBERS .2. DEPOSITION OF CLAY ON FIBERS IN THE PRESENCE OF POLY(ETHYLENIMINE), Colloids and surfaces. A, Physicochemical and engineering aspects, 71(1), 1993, pp. 105-114
The rate of deposition of clay particles on fibers dispersed in water
was determined as a function of the amount and the sequence of poly(et
hylenimine) addition. The polymer was introduced either to a mixture o
f fibers and clay or to only one of the components prior to addition o
f the second one. The primary role of the positively charged polymer w
as to adsorb onto the negatively charged components, thus modifying th
eir surfaces and consequently promoting their interaction. It has been
established that the extent and rate of particle deposition result fr
om an interplay of several kinetic factors, namely the rate of polymer
adsorption on fibers and on clay, the rate of collision between clay
particles and fibers, and the rate of clay particle aggregation. Under
the conditions of low shear rate, the polymer adsorption on fibers is
a rather slow process and is comparable to the rate of deposition of
dispersed clay particles on fibers. In contrast, polymer adsorption on
clay particles proceeds at a faster rate, causing aggregation of the
particles. The deposition of aggregates is considerably faster than th
at of dispersed clay particles.