POLYMERIZATION OF ACRYLAMIDE IN INVERSE MICROEMULSION IN THE PRESENCEOF MIXTURES OF OLEOPHILIC AND HYDROPHILIC SURFACTANTS

The preparation of single-phase toluene/sodium lhexyl)sulfosuccinate(A OT)/water/acrylamide/sodium dodecyl sulfate(SDS) inverse microemulsion s is described and their properties prior to polymerization (macrovisc osity as a function of volume fraction Phi(alpha w) of the dispersed a queous (water + acrylamide(AAm) + SDS) phase, and of SDS/AAm mass rati o) are studied. At 20 degrees C three viscosity maxima are observed. A t 50 degrees C all three peaks remain, the viscosity of the first and third peak, respectively, is lowered to 5-8 mPa . s while the second, most prominent peak still marks the level of ca. 250 mPa . s. The poly merization of acrylamide in dispersion systems is initiated by water-s oluble ammonium peroxodisulfate (APS) and oil-soluble dibenzoyl peroxi de (DBP) at 60 degrees C. The polymerization rate of acrylamide for a given [toluene]/[AOT] molar ratio and AAm/water mass ratio monotonical ly decreases for Phi(aw) values greater than 20%. The polyacrylamide v iscosity molecular mass increases up to a Phi(aw) value of ca. 30%, ir respective of the nature of initiator. For Phi(aw) values over 30% the viscosity molecular mass of polyacrylamide seems to level off with so me signs of shallow minimum close to Phi(aw) of 50%.