Ternary microemulsions of vinylic and acrylic monomers

Donescu, D.; Fusulan, Liana; Petcu, Cristian; Vasilescu, Marilena; Smarandache, Carmen; Capek, Ignác

doi:10.1016/s0014-3057(02)00029-0

Cited by 11 publications

(10 citation statements)

References 37 publications

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“…The CMC of the system employed was found to be 7.7 mmol/L, which agrees with values previously reported at similar conditions [2] and below to that reported in pure water. [8] Donescu et al [9] found that hydrophobic monomers are solubilized toward the hydrocarbon interior of the micelles whereas the hydrophilic ones, toward the polar head of the surfactant, this localization of the hydrophilic monomers (water solubility of VAc % 2.5 g/100 g of water [10] ) have a synergistic effect as a co-emulsifier by introducing enough separation between the sulfate groups. However, it has been reported that the CMC of surfactants in the presence of water soluble monomers does not change upon further addition of monomer beyond its saturation value.…”

Section: Critical Micelle Concentrationmentioning

confidence: 99%

Surfactant Concentration Effects on the Aqueous Phase Polymerization of Vinyl Acetate

Martínez‐Gutiérrez

Ovando‐Medina

Peralta

2009

Macromolecular Symposia

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Summary: Vinyl acetate (VAc) in concentrations below the water saturation value was polymerized by batch processes at 60 8C using low surfactant concentrations of sodium dodecyl sulfate (SDS) and potassium persulfate (KPS) as initiator. The effects of surfactant concentration on the reaction kinetics, particle formation and molecular weight were studied. It was found that the average particle diameters decrease between 277 and 18.7 nm as the surfactant concentration is increased from 0 to 11 mmol/L, whereas the weight average molecular weight (Mw) decreases also, with values between 8.7 Â 10 5 Mw 1 Â 10 5 Da. It was observed that particle size distributions are strongly affected by the addition of small amounts of surfactant. For the low monomer concentrations used in the polymerizations (0.0137 g/cm 3 of water), particles were very stable and no coagulation was observed. High reaction rates were found in all polymerizations. When no SDS was added to the system, lower polymerization rates were obtained at the onset of the reaction due to the low rate of particle formation. The behavior of polymerization rate was inversely proportional to the surfactant concentration, which was ascribed to the increase in the average number of radicals per particle.

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Section: Critical Micelle Concentrationmentioning

confidence: 99%

Surfactant Concentration Effects on the Aqueous Phase Polymerization of Vinyl Acetate

Martínez‐Gutiérrez

Ovando‐Medina

Peralta

2009

Macromolecular Symposia

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“…The n-butanol molecules are intercalated between the AOT molecules, reducing further the interfacial tension of monomer swollen micelles. As demonstrated by Donescu et al [23], polar monomers like VAc remain near to the polar head of the surfactant molecules, acting as cosurfactant, in addition, the presence of n-butanol increases this interaction of VAc molecules with polar heads of surfactant.…”

Section: Phase Behaviormentioning

confidence: 85%

“…It has been shown that in oil-in-water microemulsion polymerization of vinyl acetate, in spite of its relatively high water solubility, the monomer has a tendency to reside inside the monomer droplets toward the polar heads of surfactant and cosurfactant molecules [12]. Besides, when alcohols are used as cosurfactants, chain transfer to alcohol molecules events is important in the polymer particles [13].…”

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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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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“…[9] In previous studies we showed that in micellar anionic systems exists a selective interaction related to monomers polarity. [19] In this work we tried to use the ternary microemulsions with St and BuA, in presence of LS, in order to achieve stable nanolatexes by polymerization. In this context we have studied the influence of the hydrophobic character of OLS and the monomer polarity related to latexes properties and solid NC materials.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Polystyrene, Poly(butyl acrylate)-Layered Silicates Nanocomposites by Polymerization in Anionic Microemulsions

Donescu

Corobea

Capek

et al. 2009

Journal of Dispersion Science and Technology

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Styrene (St) and butyl acrylate (BuA) microemulsion polymerizations were investigated in presence of layered silicates (LS) and sodium dodecyl sulfate (SDS) as surfactant. Two main LS categories were used: one in the sodium form as Na montmorillonite (MMT) and the other in organomodified form LS (OLS) with quaternary ammonium salts having different hydrophobic modifiers. The swelling capacity of OLS in presence of monomers with different polarity is more pronounced for partners with closer hydrophobicity to St. The latexes obtained by microemulsion polymerization showed larger particles size for BuA polymer and BuA copolymer with sulfonated styrene than for St. Analyzing the dried hybrid polymers by XRD, we found structures which corresponds to exfoliated LS. The thermal behavior of hybrids, examined by TGA, showed higher rates of decomposing temperatures in the case of OLS, in comparison with the NaMMT hybrids. The obtained hybrids were evaluated by DLS, FTIR, DSC, and SEM.

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Ternary microemulsions of vinylic and acrylic monomers

Cited by 11 publications

References 37 publications

Surfactant Concentration Effects on the Aqueous Phase Polymerization of Vinyl Acetate

Surfactant Concentration Effects on the Aqueous Phase Polymerization of Vinyl Acetate

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

Synthesis and Characterization of Polystyrene, Poly(butyl acrylate)-Layered Silicates Nanocomposites by Polymerization in Anionic Microemulsions

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