STABILITY OF AQUEOUS FOAMS WITH POLYMER ADDITIVES .3. MEASUREMENTS AND CALCULATIONS OF STABILITY OF FOAMS GENERATED AT DIFFERENT PRESSURES

The stability of aqueous foams with polymer additives has been studied at different generation pressures. While the stability increases sign ificantly with the increase of generation pressure for foams without a ny additive, it, however, changes weakly with the change in generation pressure for foams with polymer additives. Consistent with the previo usly reported studies, it is found that the foam stability (drainage h alf-life) increases, primarily due to the decrease of bubble size, at higher generation pressures, when the foam is produced in a packed bed . Calculations of drainage half-life were conducted using a modified l amella drainage model as well as a simple network model. It is found t hat the network model predictions agree reasonably well with measureme nts. (C) 1994 Academic Press, Inc.