Rg. Alargova et al., Dynamic light scattering study of polystyrene latex suspended in water at high temperatures and high pressures, COLL SURF A, 183, 2001, pp. 303-312
Citations number
24
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
The stability of monodispersive polystyrene spheres suspended in water has
been studied at high pressure and temperature in the range of 0.1-28 MPa an
d 24-325 degreesC. The diffusion coefficient of the latex was measured with
dynamic light scattering using a special experimental cell for performing
measurements at elevated pressure and temperature. It is found out that the
influence of the increased pressure on the measured results is negligibly
small. The elevation of temperature significantly increases the particle di
ffusion coefficient due to the viscosity decrease of the medium, but its de
pendence is well described by the theoretical predictions for the diffusion
coefficients of the particles with constant size calculated at 24-275 degr
eesC. This result means that the polystyrene spheres do not change in size
and the suspension remains stable below 275 degreesC at least in the time s
cale of our experiments. The change in the size of latex was observed at 30
0 and 325 degreesC. The measured decrease of the diffusion coefficient with
time could be related to the increase in the average particle size due to
the beginning of the coagulation process, but some other effects as swellin
g of polystyrene might be also possible. (C) 2001 Elsevier Science B.V. All
rights reserved.