Effect of styrene on the polymerization of acrylamide in inverse microemulsion

Abstract

The macroviscosity of a single-phase toluene/styrene/sodium bis(2-ethy1hexyl)sulfosuccinate/water/acrylamide Winsor IV inverse microemulsion prior to polymerization as a function of the volume fraction QaW, of the dispersed aqueous (water + acrylamide) phase at 20°C reaches three distinct maxima of 16, 66, and 30 mPa*s for @aw values 25%, 46%, and 62%, respectively. At 60°C, the viscosity maxima practically vanish and the macroviscosity of the dispersion systems is in the range of 5-7 mPa-s. The overall maximum (co)polymerization rate of acrylamide and styrene increases with increasing @aw. On the other hand, an increase of the mass ratio styrene/toluene leads (for a given eaW value) to a decrease of the overall maximum (co)polymerization rate regardless of the nature of the initiator used. This points to an effective competition between monomer in the oil phase (slow homopolymerization of styrene and/or (co)polymerization of styrene with acrylamide dissolved in the oil phase) and monomer in the water pools of inverse micelles (rapid homopolymerization of a major part of acrylamide) for initiator radicals and/or (co)oligomer radicals.

Inverse microemulsion polymerization of acrylamide in the presence of N,N ‐dimethylacrylamide

“…In case of significant partitioning of the (co)monomer and/or initiator in both phases (or better at the locus of (co)polymerization) polymerization of the monomer in the oil phase contributes to the overall polymer formation in an inverse microemulsion. It was claimed 5) that in such a case the simple mechanism of polymer particle formation derived for water pool monomer polymerization 6) should be modified and/or a new mechanism should be proposed.…”

“…The kinetic study of the effect of oil-soluble monomer styrene located in the continuous oil phase on the acrylamide polymerization in inverse microemulsion 5) pointed to an effective competition between the monomers in the oil phase (slow homopolymerization of styrene and/or (co)polymerization of styrene with acrylamide dissolved in the oil phase) and the monomers in the water pools of inverse micelles (rapid homopolymerization of a major part of acrylamide) for initiator radicals and/or (co)oligo-mer radicals. The proposed model for the characterization of the acrylamide (co)polymerization with styrene in inverse microemulsion seems to be applicable, however, for oil phase polymerization reactions only 5) .…”

“…The (co)polymerization of monomers differing reasonably in their water solubilities in heterogeneous polymerization systems, such as water-in-oil dispersions, was studied recently [1][2][3][4][5] . It was shown that the conversion curves of the copolymerization of acrylamide with styrene and/ or methyl methacrylate in inverse microemulsion display the typical course of a "dead-end" polymerization.…”

Preparation of partly hydrophobized, crosslinked polyacrylamide particles by terpolymerization of acrylamide/N,N-methylenebisacrylamide/styrene in inverse microemulsion

“…This was explained as a result of effective competition between monomer in the oil phase (slow homopolymerization of S besides (co)polymerization of S with AAm dissolved in the oil phase) and monomer AAm in the water pools of inverse micelles (rapid homopolymerization of a major part of AAm) for initiator radicals and/or (co)oligomer radicals. 5 The present paper is devoted to the polymerization of a termonomer system AAm/MBAAm/S in an inverse microemulsion T/S/AOT//water//AAm/ MBAAm/APS or DBP. The inverse microemulsion was characterized by the use of a high molar ratio of { [T] [S]}/[AOT] = 20.1.…”

“…This was actually found in our previous works on AAm/S copolymerization in an inverse microemulsion. 1,2,5 Thus the admixture of any comonomer characterized by a slower propagation rate than AAm should, for the kinetic reasons, decrease the overall copolymerization rate in the system. The copolymerization of AAm with N,Ndimethylacrylamide in inverse microemulsion 13 should be mentioned as an another example.…”