Polymerization of acrylamide in styrene containing inverse microemulsions:polymerization kinetics and polymer product composition studies

The kinetics of free-radical homopolymerization and copolymerization of acr ylamide (AAm) and styrene (S) initiated by water-soluble ammonium peroxodis ulfate, (APS) or by toluene-soluble dibenzoyl peroxide (DBP) in inverse mic roemulsion toluene/S/AOT (sodium bis(2-ethylhexyl)sulfosuccinate)/water/AAm characterized by a low volume fraction of the aqueous phase (Phi (aw) appr oximate to 0.08) as a function of the concentration of S in the oil phase o f the inverse microemulsion system have been studied. S strongly decreases the rate of AAm/S (co)polymerization. This is valid for both APS and DBP in itiators. Kinetic measurements indicate the important role for cross-initia tion of water soluble AAm growing chains and of oil soluble S analogues act ivated by the primary free-radicals generated from APS (or from DBP) in the dispersed water droplets (or in the continuous oil-phase) of the inverse m icroemulsion, respectively. With inverse microemulsions containing toluene (70.73%)/S (2.44%)AOT(17.56 %)/water (7.32 %)/AAm (1.95%), after polymeriza tion (initiator APS, 3.04 x 10(-2)mol dm(-3) of water) and separation of th e polymeric components, the following yields were obtained: AAm/S (co)polym er (89.20mass%; ie 62.24mass% of AAm structural units and 26.96mass% of S s tructural units), polyacrylamide (9.4mass%) and polystyrene (1.4mass%). (C) 2000 Society of Chemical Industry.