Vn. Moraru et Fd. Ovcharenko, THE INVESTIGATION OF THE GEL-FORMATION MECHANISM IN AQUEOUS DISPERSIONS OF THE OXIDIZED GRAPHITE AND DIAMOND, Journal de chimie physique et de physico-chimie biologique, 93(5), 1996, pp. 1051-1064
The experimental dependencies of the theological properties of the dis
persions of two inorganic polymers (oxidized graphite and diamond) on
the concentration of the disperse phase and medium pH at constant ioni
c strength of background electrolyte (KCI) have been obtained and the
results have been compared with calorimetric data as well as with pH-d
ependencies of the surface charge (sigma) the stability (D) and the di
spersion zeta-potential. It is established that in the whole pH region
the change in the plastic viscosity (eta), the dynamic yield limit (t
au(B)) and the thixotropy of the dispersions is precisely correlated w
ith the change of their electrosurface properties and the specific hea
t of the graphite and diamond wetting (q). The maximum dispersion stru
cture-formation is observed in the vicinity of the zero charge point a
nd meets the minimum q values and the system stability. A strong depen
dence pf the dispersion gel-formation and thixotropy on the particle a
nisometry has been revealed The conclusion that gel-formation in hydro
dispersions of the oxidized graphite and diamond is the result of the
near and/or further coagulation interaction of particles through liqui
d interlayers in the medium controlled by the lyophilicity and the ele
ctrosurface forces has been drawn on the obtained data. This conclusio
n agrees with the results of the calculation of the graphite and diamo
nd particle's pair interaction potential curves within the DLVO theory
with the allowance for the structural forces.