Micellar Aqueous Phase Polymerization of Acrylamide

The kinetics of aqueous phase radical polymerization of acrylamide initiated by ammonium peroxodisulfate (APS) and 2,2 -azobisizobutyronitrile (AIBN) were studied in the presence of the non-ionic hydrophilic Tween-20 and hydrophobic Tween-85. The polymerization rate vs. conversion curve is described by a curve with two or three rate intervals and the maximal rate is located at medium conversion. This behavior strongly deviates from the kinetic model of the ideal solution polymerization with the steady-state kinetics at low and medium conversions. On the contrary, the present data indicate the kinetics typical for the transparent heterogeneous–micellar or microemulsion polymerization. The associates of polyacrylamide and acrylamide play the role of active particles. Indeed, the light scattering measurements confirmed the presence of polyacrylamide nanoparticles in both polymerization systems with and without emulsifier. The intra- and intermolecular association of polyacrylamide with its monomer is suggested to be the dominant process which induces the formation of particles responsible for the kinetics typical for the micellar or microemulsion polymerization. The experimental data show that the dependence of the maximal rate of polymerization (R p,max) vs. conversion is the result of polymerization within the nanoscaled polymer aggregates and not by the gel effect. R p,max decreases with increasing emulsifier concentration and the decrease is much more pronounced with hydrophilic emulsifier. Polymerization is faster for the APS-initiated system than for the AIBN-initiated one. The radical polymerization of AAm polymerization with and without emulsifier was discussed in terms of the formation of polymer chain aggregation (nanoparticle) into polymer chains as a main reaction locus.

[1]  I. Capek.  Miniemulsion Polymerization of Styrene Initiated by Tween-surfinit , 2010 .

[2]  L. Fialová,et al.  On the Kinetics of Inverse Emulsion Polymerization of Acrylamide , 2008 .

[3]  Y. Sarov,et al.  Polymerization of vinyl monomers in separated Winsor II (w/o) and Winsor I (o/w) microemulsion phases. Part 1: preparation and characterization of polymerizable vinyl-monomer-containing microemulsions , 2006 .

[4]  C. Magesh,et al.  Microemulsion co-polymerization of methyl methacrylate with acrylonitrile , 2005 .

[5]  P. Sedlák,et al.  Sterically stabilized emulsion polymerization of 2-ethylhexyl acrylate , 2004 .

[6]  I. Capek.  The inverse mini-emulsion polymerization of acrylamide , 2003 .

[7]  Hong-Ru Lin.  Solution polymerization of acrylamide using potassium persulfate as an initiator: kinetic studies, temperature and pH dependence , 2001 .

[8]  Koichi Ito,et al.  Micellar copolymerization of styrene with a poly(ethylene oxide) macromonomer in water to a unimolecular graft copolymer micelle , 2000 .

[9]  F. Candau,et al.  Hydrophobically-modified polyacrylamides prepared by micellar polymerization , 1999 .

[10]  I. Capek,et al.  Microemulsion and emulsion polymerization of butyl acrylate—I. Effect of the initiator type and temperature , 1995 .

[11]  I. Capek,et al.  Microemulsion polymerization of butyl acrylate. 1. Effect of initiator type and concentration , 1994 .

[12]  I. Capek,et al.  Kinetic investigation of the dispersion polymerization of N,N′‐methylenebis(acrylamide) in the presence of various emulsifiers , 1990 .

[13]  R. M. Fitch,et al.  Kinetics of photopolymerization of acrylamide in AOT reverse micelles , 1989 .

[14]  I. Capek.  Emulsion copolymerization of acrylonitrile and butyl acrylate, 10. Effect of 1,1-diphenyl-2-picrylhydrazyl on the polymerization process† , 1989 .

[15]  I. Capek,et al.  Emulsion copolymerization of acrylonitrile and butyl acrylate, 7. Effect of concentration and type of emulsifier on polymerization kinetics , 1988 .

[16]  J. Barton̆,et al.  Aqueous polymerization of vinyl monomers in the presence of surfactants, 1. Acrylamide , 1985 .

[17]  K. O'driscoll.  An analysis of the factors affecting the pressure dependence of the termination rate constant kt , 1979 .

[18]  Archie E. Hamielec,et al.  High Conversion Diffusion-Controlled Polymerization , 1979 .

[19]  E. Lissi,et al.  High‐conversion polymerization. IV. A definition of the onset of the gel effect , 1979 .

[20]  K. Mittal,et al.  Micellization, solubilization, and microemulsions , 1977 .

[21]  D. Misra,et al.  Aqueous polymerization of acrylamide initiated by acidic potassium permanganate–ascorbic acid redox system , 1973 .

[22]  E. Nyquist,et al.  Functional monomers; their preparation, polymerization, and application , 1973 .

[23]  P. F. Onyon.  Polymer Handbook , 1972, Nature.

[24]  G. Reed,et al.  Diffusion-controlled termination during the initial stages of free radical polymerization of methyl methacrylate , 1961 .

[25]  R. H. Ewart,et al.  Kinetics of Emulsion Polymerization , 1948 .