S. Furlong et al., Water enclosed within the droplets of bitumen emulsions and its relation to viscosity changes during storage, COLL SURF A, 152(1-2), 1999, pp. 147-153
Citations number
15
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
The viscosity of bitumen emulsions is influenced by the presence of bitumen
droplets which also contain an internal aqueous phase, effectively increas
ing the disperse phase volume. In this study the concentrations of this int
ernal water in a range of commercial emulsion formulas are determined by a
differential scanning calorimetry (DSC) technique. The choice of emulsifier
and the salt content of the bitumen influence the amount of internal water
, which ranges up to 10% and strongly affects viscosity. Changes in emulsio
n viscosity during storage more closely parallel changes in the level of in
ternal water rather than changes in particle size. Typically the internal w
ater phase increases during storage, followed by a decrease and these chang
es generally occur over a few days or weeks depending on the temperature. S
alt in the bitumen causes an osmotic swelling of the internal water phase w
hich starts to occur inside the colloid mill and can be followed quantitati
vely by the DSC technique. (C) 1999 Elsevier Science B.V. All rights reserv
ed.