Structure and Dynamics of Polymerizable Microemulsions

Full, A. P.; Kaler, Eric W.

doi:10.1021/la00021a014

Cited by 16 publications

(24 citation statements)

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“…The phase behavior of this system was studied previously by some of us in the absence of KBr at both 25 and 60 °C. , Increasing the temperature causes the microemulsion phase region to become more narrow for solutions <20 wt % DTAB relative to H 2 O−brine. The effect of using D 2 O instead of H 2 O was also studied previously, and the phase boundaries shift in an irregular manner as salt is added . The high viscosity of samples at high surfactant concentrations prevents exact determination of phase boundaries (dashed lines).…”

Section: Resultsmentioning

confidence: 84%

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Microemulsion Polymerization of Styrene: The Effect of Salt and Structure

et al. 1996

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The polymerization of styrene in oil-in-water microemulsions made with the cationic surfactants dodecyltrimethylammonium bromide or chloride is studied as a function of inorganic electrolyte (KBr, KCl, or K2SO4) concentration. The resulting microlatex is stable, but as the electrolyte concentration increases, both the average radius and the polymer molecular weight decrease. The presence of electrolyte slows the polymerization rate and diminishes final conversion as followed by gravimetry, dilatometry, and calorimetry. Both particle radius, determined by quasielastic light scattering, and molecular weight show only limited growth as styrene conversion increases, suggesting continuous nucleation of latex particles and termination by chain transfer to monomer. Small-angle neutron scattering (SANS) of undiluted parent and polymerized microemulsions shows that a unimodal population of swollen micelles evolves into a bimodal population of empty micelles coexisting with large polymer particles. Structural details of the parent and polymerized microemulsions as determined by SANS are used to assess nucleation mechanisms previously proposed for emulsion polymerization.

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Section: Resultsmentioning

confidence: 84%

“…Recently the structure of the parent microemulsions with and without salt has been probed by quasielastic light scattering (QLS) and small-angle neutron scattering (SANS) . The combination of QLS and SANS experiments provides self-consistent information about microstructure and interparticle interactions.…”

Section: Introductionmentioning

confidence: 99%

Microemulsion Polymerization of Styrene: The Effect of Salt and Structure

et al. 1996

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“…QLS and SANS measurements made on DTAB microemulsions of similar compositions but containing only styrene indicated the presence of DTAB micelles swollen with styrene dispersed in a DTABsaturated aqueous phase. 13 It is unlikely that the addition of the relatively small amounts of acrylonitrile changes the structure of the microemulsions reported here.…”

Section: Micrographs Of Latex Particles From the Microemulsion Copolymentioning

confidence: 75%

A Comparison of Emulsion and Microemulsion Copolymerization of Styrene and Acrylonitrile

Mendizábal

Rodríguez-Ruvalcaba

Rabelero

et al. 1995

International Journal of Polymeric Materials and Polymeric Biom

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The synthesis of styrene-acrylonitrile (SAN) copolymers by emulsion or microemulsion polymerization using either a water-soluble (potassium persulfate or KPS) or a water-insoluble (AIBN) initiator is presented here. The surfactant used was dodecyltrimethylammonium bromide (DTAB) or sodium dodecylbenzenesulfonate (SDBS). Polymerization in DTAB microemulsions initiated with AIBN are faster and have higher conversions than those initiated with KPS, but the opposite effect is observed for emulsion polymerization. In both emulsion and microemulsion polymerizations, high molecular weights (2-4 x lob Dalton) SAN copolymers are produced with composition richer in styrene (YAN = 81/19 w/w) than the initial feed composition (75/25 w/w). Latex produced by microemulsion polymerization contain particles two-to three-fold smaller than those prepared by emulsion polymerization.Styrene-acrylonitrile copolymers (SAN) are thermoplastics of commercial importance because their flexural impact, tensile strength and chemical resistance are significantly better than those of polystyrene and other similar polymers. '.* SAN copolymers also have good gloss, transparency and high deflection temperature. The physical properties of SAN copolymers are enhanced by increasing molecular weight and acrylonitrile content up to about 35 mol%, although there is a loss of processability and a slight decrease in transparency.

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“…Some examples areas follows: Gan and coworkers produced PMMA in ternary microemulsions using the cationic surfactants stearyl trimethylammonium chloride (STAC), cetyl trimethylammonium bromide (CTAB), and dodecyl trimethylammonium bromide (DTAB) with either a water‐soluble or an oil‐soluble initiator and found that the longer the hydrophobic chain length of the surfactant, the smaller the latex particles 23. Kaler and coworkers also have produced small latexes from styrene and from several different methacrylic esters using cationic surfactants 12, 19, 24–26. Larpent and Tadros found optimum mixtures of nonionic surfactants [Triton N‐150 and Triton N‐57, nonylphenoxy poly(ethylene glycols) having averages of 15 and 5 ethylene oxide units, respectively], to form microemulsions of MMA and of styrene in water, and produced small latex particles at varied surfactant‐to‐monomer ratios using ascorbic acid/hydrogen peroxide as a redox initiator 27…”

Section: Introductionmentioning

confidence: 99%

Methacrylate-based nanoparticles produced by microemulsion polymerization

Özer

Beşkardeş

Pi̇şki̇n

2000

J. Appl. Polym. Sci.

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Nanoparticles of methacrylate comonomers were obtained by microemulsion polymerization by using cetyltrimethylammonium bromide as the stabilizer. Stable and bluish transparent latexes were produced from these polymerizations in which potassium persulphate was used as the initiator. The viscosity average molecular weights were in between 6 × 105 and 1.25 × 106. The average diameters of the latex particles were in the range of 20–40 nm, which was obtained by scanning tunneling microscopy. The average particle diameter increased both with an increase in the relative amount of the comonomers and their type. The glass transition temperatures of these polymers obtained by DSC were in the range of 30–103°C, and decreased with the increase in the comonomer ratio. The comonomer ratios in the final copolymers were obtained from 1H‐NMR spectra, which were smaller than those ratios used in the original recipes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 569–575, 2000

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Structure and Dynamics of Polymerizable Microemulsions

Cited by 16 publications

References 0 publications

Microemulsion Polymerization of Styrene: The Effect of Salt and Structure

Microemulsion Polymerization of Styrene: The Effect of Salt and Structure

A Comparison of Emulsion and Microemulsion Copolymerization of Styrene and Acrylonitrile

Methacrylate-based nanoparticles produced by microemulsion polymerization

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