Polymerization of vinyl acetate in ternary microemulsions stabilized with hexadecyltrimethylammonium bromide

López, Raúl G.; Treviño, María E.; Salazar, L. V.; Peralta, René D.; Becerra, F.; Puig, J. E.; Mendizábal, Eduardo

doi:10.1007/s002890050067

Cited by 21 publications

(21 citation statements)

References 16 publications

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“…However, because of chain transfer reactions to polymer at high conversions during the emulsion polymerization of VAc, highly branched polymers are obtained [5][6][7][8]. On the other hand, in batch microemulsion polymerization of VAc in threecomponent cationic or anionic microemulsions chain transfer reactions to monomer control chain termination, even at high conversions, in contrast to emulsion polymerization [9][10][11].…”

Section: Introductionmentioning

confidence: 91%

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Kinetics and monomer partitioning during polymerization of vinyl acetate in microemulsions stabilized with AOT and n-butanol

Herrera¹,

Ovando‐Medina

López³

et al. 2014

Colloid Polym Sci

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Vinyl acetate (VAc) was polymerized in microemulsion using sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as surfactant and n-butanol (n-BuOH) as the cosurfactant (1:1, wt/wt) with potassium persulfate (KPS) as initiator. The effects of monomer, surfactant, and initiator concentration, as well as the temperature on the kinetics, particle size, and molar masses were studied. It was observed that polymerization rate increases as monomer, initiator, and temperature increases; however, the opposite was observed as surfactant concentration increases. Average particle diameters (Dp)< 50 nm and polymers with weight average molar masses (Mw) between 2.7×10 5 and 7.5×10 5 g/mol were obtained. For low amounts of stabilizing agents (AOT and n-BuOH), a bimodal molar mass distribution (MMD) was obtained. As nbutanol concentration increased, Mw decreases and a monomodal MMD was observed, which can be explained because chain transfer events are promoted by the presence of n-BuOH. A thermodynamic model was implemented to simulate the partitioning of VAc in the presence of n-BuOH between the phases throughout polymerization. It was found from simulations that microemulsion droplets are depleted fast at 5 % conversion and, due to the high water solubility of VAc, most of the monomer (70 %) and n-BuOH (97 %) reside in the aqueous phase at the beginning of polymerization, which indicates that both homogeneous and micellar nucleation are present.

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Section: Introductionmentioning

confidence: 91%

“…To date, much work has been published on the batch polymerization of vinyl acetate in microemulsion media [9,[16][17][18]. Most of it deals with the use of different surfactants (cationic, anionic, non-ionic, etc.).…”

Section: Introductionmentioning

confidence: 99%

Kinetics and monomer partitioning during polymerization of vinyl acetate in microemulsions stabilized with AOT and n-butanol

Herrera¹,

Ovando‐Medina

López³

et al. 2014

Colloid Polym Sci

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“…It has been reported [25,26] that chain transfer to monomer is the controlling termination mechanism for most of oil-in-water (o/w) microemulsion polymerization. The termination by chain transfer reactions to monomer will regulate the M w of polymer.…”

Section: Characteristics Of Latexes During the Continuous Addition Ofmentioning

confidence: 99%

Semi-continuous emulsion copolymerization of butyl methacrylate with polymerizable anionic surfactants

Chen

2004

Polymer

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“…Also, isotactic poly(methyl methacrylate) can be produced by free radical microemulsion polymerization whereas the atactic polymer is always obtained in emulsion polymerization 9) . Recently, we reported the synthesis of poly(vinyl acetate) by polymerization in three-component microemulsions stabilized with cetyltrimethylammonium bromide (CTAB), where most of the polymer appears to be linear even at high conversions because chain transfer reactions to monomer control the molar mass distribution 10) . By contrast, in the batch emulsion polymerization of this monomer, linear polymer can be obtained only at low conversions where chain transfer to monomer is the controlling chain termination mechanism; however, at conversions larger than ca.…”

Section: Introductionmentioning

confidence: 99%

“…Only two reaction rate intervals are detected as a function of conversion (Fig. 2B), like in the microemulsion polymerization of other monomers 8,10,[15][16][17][18][19][20][21] . Notice that the conversion (ca.…”

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confidence: 99%

Electrostatic effects on the polymerization of vinyl acetate in three-component anionic microemulsions

Sosa¹,

López²,

Peralta³

et al. 1999

Macromol. Chem. Phys.

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SUMMARY: The polymerization of vinyl acetate (VA) in three-component microemulsions stabilized with Aerosol OT is examined as a function of pH. To investigate the role of electrostatic effects on the polymerization kinetics, two initiators (potassium peroxodisulfate and V-50) that decompose into negatively-charged and positively-charged free radicals, respectively, were used. The pH of the reacting medium influences the efficiency of potassium peroxodisulfate (KPS) to initiate the reaction but it has no effect on V-50 efficiency. At neutral pH, faster reaction rates and higher conversions (after 90 min) are achieved with KPS. At equal free radical fluxes and pH's, KPS gives faster reaction rates and larger conversions than V-50 because of the different electrostatic interactions of KPS and V-50 free radicals with the negatively-charged microemulsion droplets and the reacting particles. Final latices contain nanosize polymer particles with particle size of ca. 30 nm in reactions initiated with KPS and between 26 and 40 nm in polymerizations initiated with V-50. In all cases, linear poly(vinyl acetate) is obtained because chain transfer to monomer is the controlling mechanism of chain growth, even at high conversions. This appears to be due to the small particle size that allows the fast desorption rate of the monomeric free radicals from the particles.

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Polymerization of vinyl acetate in ternary microemulsions stabilized with hexadecyltrimethylammonium bromide

Cited by 21 publications

References 16 publications

Kinetics and monomer partitioning during polymerization of vinyl acetate in microemulsions stabilized with AOT and n-butanol

Kinetics and monomer partitioning during polymerization of vinyl acetate in microemulsions stabilized with AOT and n-butanol

Semi-continuous emulsion copolymerization of butyl methacrylate with polymerizable anionic surfactants

Electrostatic effects on the polymerization of vinyl acetate in three-component anionic microemulsions

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