POLYMERIZATION OF ACRYLAMIDE IN SINGLE-PHASE INVERSE DISPERSION-SYSTEMS AT HIGH-VOLUME FRACTIONS OF DISPERSED PHASE

The preparation of single-phase inverse microemulsions of toluene/sodi um bis(2-ethylhexyl)sulfosuccinate (AOT)/water/acrylamide (AAm) is des cribed and their properties prior to polymerization (macro and microvi scosity as a function of volume fraction Phi(aw) of the dispersed aque ous (water + acrylamide) phase, of the [toluene]/[AOT] molar ratio and of the acrylamide/water mass ratio) were studied. The polymerization of acrylamide in dispersion systems was initiated by the oil-soluble i nitiator dibenzoyl peroxide at 60 degrees C. The polymerization rate o f acrylamide for a given [toluene]/[AOT] molar ratio and AAm/water mas s ratio monotonically decreases beyond a Phi(aw) value of 20%. The pol ymer particle size in polymerized systems as well as the molecular mas s of polymer in the polymer particles increase on increasing the acryl amide concentration in the aqueous phase and/or the Phi(aw) values of the dispersion system. On increasing the surfactant AOT concentration both polymer particle size and polymer molecular mass decrease for a g iven set of other relevant parameters of the dispersion system (i.e. [ toluene]/[AOT] and AAm/water ratios). The polymerized inverse dispersi on system can be converted to an oil-in-water dispersion by addition o f water.