Surfactant concentration effects on the microemulsion polymerization of vinyl acetate

Gómez-Cisneros, M.; Treviño, María E.; Peralta, René D.; Rabelero, M.; Mendizábal, Eduardo; Puig, J. E.; Cesteros, Carlos; López, Raúl G.

doi:10.1016/j.polymer.2005.02.044

Cited by 29 publications

(14 citation statements)

References 28 publications

(43 reference statements)

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“…Above the CMC ([SDS] ¼ 11 mmol/L) the average particle size is typical of those reported by microemulsion polymerization of VAc. [11,21] Micellar nucleation is the most important mechanism of particle formation in this type of polymerization and although there is high surfactant concentration it is considered that coagulative nucleation does not compete with micellar nucleation because of the high interfacial area of the polymer particles and the monomer droplets, which capture most of the oligomeric radicals formed in the aqueous phase.…”

Section: Critical Micelle Concentrationmentioning

confidence: 99%

“…The probability of radical desorption from a particle, depends on the characteristic diffusion time of a monomeric radical on the length scale of the particle size and the time scale of propagation, which means that the probability of radical desorption diminishes as the particle becomes bigger. [21] Under these circumstances, the average number of radicals per particle wascalculated from equation 2. Table 2 shows the average number of radicals per particle obtained at different conversions using different surfactant concentration.…”

Section: Molar Massmentioning

confidence: 99%

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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%

Section: Molar Massmentioning

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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“…It consists of a surfactant, a water-immiscible oil and a cosurfactant in a proper ratio so that a single, optically transparent and thermodynamically stable phase is formed [29]. Due to the special structure, microemulsion exhibits good wetting ability, moderate viscosity, low interfacial tensions and high solubilization for both hydrophilic and hydrophobic compounds [29], resulting in its wide application in separation science [30], polymerization [31], oil recovery [32], removal of organic pollutants from water [33] and ex situ soil washing [34]. However, the use of O/W microemulsion as alternative solvent system in ASE has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Application of surfactants and microemulsions to the extraction of pyrene and phenanthrene from soil with three different extraction methods

Song

Lin

2007

Analytica Chimica Acta

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In the present work, the use of surfactants and oil-in-water (O/W) microemulsions as alternative extractants in accelerated solvent extraction (ASE) for the extraction of polycyclic aromatic hydrocarbons (pyrene and phenanthrene) from soils was investigated. In particular, the effect of each individual component within the microemulsions, i.e., oil phase, surfactant and co-surfactatnt, and extraction conditions on the percentage recovery was systematically studied. When compared to the water and organic solvent, the important findings were that the common surfactant solutions at the concentrations above their critical micelle concentrations (CMC) were shown to enhance the percentage recovery at the lower extraction temperature. Moreover, the highest percentage recovery can be obtained using microemulsion as the extractant. The chemical component within the microemulsions and relative amounts of the oil phase appeared to play a much more significant role in ensuring high percentage recovery. Finally, an overall comparison between the percentage recoveries obtained with ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and ASE using organic solvents, surfactants and microemulsions as extractants was exhibited.

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“…However, these values are typical for studies of this type of addition polymerization. [22][23][24] The linear effect of BuOH was again apparent; however, demonstrated a negative sign to the coefficient (L, 22.892) suggesting that polydispersity was decreased slightly upon an increase in BuOH concentration. The effects of temperature (Q, 12.182) and SDS (12.326) were also observed to be significant and these showed positive effects (therefore increasing polydispersity) as noted from the signs preceding the magnitude coefficients (Table III).…”

Section: Molecular Weight Of P(st-co-mma)mentioning

confidence: 99%

“…Although not clearly understood, some explanations for these observations included the macroradical chain transfer to the cosurfactant and film formation around the surface of the micelle that shield polymer radicals. [22][23][24] In this study, a series of poly(styrene-co-methyl methacrylate) (P(St-co-MMA)) was synthesized under various concentrations of n-butanol, surfactant, temperature, and monomer mixture composi-tion. The aim was to investigate the effects of the experimental factors on the molecular weight, copolymer particle size, and chemical composition of the copolymer.…”

Section: Introductionmentioning

confidence: 99%

Effects of the cosurfactant 1‐butanol and feed composition on nanoparticle properties produced by microemulsion copolymerization of styrene and methyl methacrylate

Otto

Vosloo

Liebenberg

et al. 2007

J of Applied Polymer Sci

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ABSTRACT:The concentration of the cosurfactant 1-butanol (BuOH) determined the polymer weight and size for a series of poly(styrene-co-methyl methacrylate)s (P(St-co-MMA)) synthesized by the free-radical (o/w) microemulsion technique. A factorial design established the levels of the experimental conditions for the polymerization i.e., concentration of the surfactant, sodium dodecyl sulfate (SDS); concentration of the cosurfactant, BuOH; temperature and ratio of the styrene (St) to methyl methacrylate (MMA). An increase in the weight-average molecular weight (M w ) and number-average molecular weight (M n ) was observed in the P(St-co-MMA) series with an increase in BuOH concentration from 1 to 5 wt %. These effects could arise from the micellar aggregation induced by interfacial BuOH. The unique micellar conditions could be exploited to synthesize copolymers of varying molecular weight and size. Additionally, the composition of the copolymers was virtually templates of the feed composition.

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Surfactant concentration effects on the microemulsion polymerization of vinyl acetate

Cited by 29 publications

References 28 publications

Surfactant Concentration Effects on the Aqueous Phase Polymerization of Vinyl Acetate

Surfactant Concentration Effects on the Aqueous Phase Polymerization of Vinyl Acetate

Application of surfactants and microemulsions to the extraction of pyrene and phenanthrene from soil with three different extraction methods

Effects of the cosurfactant 1‐butanol and feed composition on nanoparticle properties produced by microemulsion copolymerization of styrene and methyl methacrylate

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