Emulsion polymerisation in the absence of an emulsifying agent and latexes based on it

Eliseeva, V. I.; Асламазова, Т. Р.

doi:10.1070/rc1991v060n02abeh001040

Cited by 10 publications

(7 citation statements)

References 1 publication

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“…The absolute values of U s are much larger than those of U m and thus contribute much stronger to the overall particle-particle interaction. Such behavior seems to be quite general as similar curves are obtained not only for the other inisurfs but also for poly(alkyl methacrylate) particles prepared with persulfate as initiator by emulsifier-free emulsion polymerization [8][9][10][11].…”

Section: Resultssupporting

confidence: 49%

“…For instance, contact angles of 65 and 94 • leads to K a values of 6 × 10 −6 and 14 × 10 −6 dyn, respectively, for Hs = 1 nm. These values were found to be useful to describe the behavior of poly(butyl acrylate) latex particles prepared by emulsifier-free emulsion polymerization [8][9][10]. Considering on the one hand the fact that polystyrene is slightly more hydrophobic than poly(butyl acrylate) and on the other hand the range of contact angels measured, which is between 86 and 73 • (cf.…”

Section: Resultsmentioning

confidence: 90%

“…As the colloidal stability of latexes is an important issue several investigations with regard to the surface forces of particle-particle interaction have been published considering latexes prepared with "classical" initiators for aqueous emulsion polymerization such as peroxodisulfates [8][9][10][11][12][13]. It turned out that these forces can be used to describe the stability of the latexes not only under the conditions of the polymerization process [8][9][10][11] but also during hydrodynamic [12] and low temperature stresses [13].…”

Section: Introductionmentioning

confidence: 99%

“…It turned out that these forces can be used to describe the stability of the latexes not only under the conditions of the polymerization process [8][9][10][11] but also during hydrodynamic [12] and low temperature stresses [13].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the colloidal stability of polystyrene particles prepared with different kinds of surface active initiators

Асламазова

Tauer

2004

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Section: Resultssupporting

confidence: 49%

Section: Resultsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the colloidal stability of polystyrene particles prepared with different kinds of surface active initiators

Асламазова

Tauer

2004

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…To explain the influence of emulsifier on the nature of the stabilization process of PMPs Yeliseyeva et al [12,13] proposed to use the emulsifier adsorption isotherms at PMPs as a main characteristic.…”

Section: The Mechanism Of Homogeneous Nucleationmentioning

confidence: 99%

An Advanced Approach on the Study of Emulsion Polymerization: Effect of the Initial Dispersion State of the System on the Reaction Mechanism, Polymerization Rate, and Size Distribution of Polymer-Monomer Particles

Khaddazh¹,

Литвиненко²

2012

Polymerization

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According to these ideas, in the presence of surfactants, the initial emulsion consists of two kinds of particles of different sizes: the monomer droplets with diameters of 5-20 microns and colloidal degree of dispersion and monomer-swollen surfactant micelles (5-10 nm).The mechanism of Harkins-Yurzhenko lied in the base of Smith and Ewart quantitative theory [5][6][7], with further refinements in the works of other authors . The main aspect of this theory is that radicals formed in the aqueous phase are trapped by the monomer swollen surfactant micelles and turn to PMP. It is assumed that only one out of every 100-1000 micelles captures a radical and becomes PMP, and the rest of the micelles are spent to stabilize the growing PMPs. Polymer-monomer particles formation ends with the disappearance of micelles of the emulsifier in the aqueous phase, after which the number of particles remains constant.Initial system contains monomer droplets with a diameter of 5-15 microns, their concentration being 10 12 -10 14 droplets/l, the monomer-swollen micelles with diameters of 5-10 nm and the number of micelles 10 18 -10 21 l -1 , and a water-soluble initiator (usually potassium persulfate) at a concentration of 1% per monomer [8]. Only a small fraction of the molecules of the monomer is located in the interior of the micelles (1-2%) and is dissolved in the aqueous phase (0.03% for styrene). In the aqueous phase, 10 14 -10 16 PMP / l are formed with a diameter in the range of 20-200 nm. Monomer droplets due to their relatively small surface area hardly compete with micelles in capturing radicals.In the polymerization process PMPs increase their size due to the diffusion of the monomer from droplets and monomer-swollen micelles which contains no radicals [1-3, 5, 9-15].Three limiting cases were considered:1. The number of free radicals in the particles is small compared with the total number of radicals, thus the average number of radicals per particle is much less that unity. 2. The average number of radicals per particle is equal to 0.5. This case is realized under following conditions: the activity of the radical in the particle persists as long as the second radical enter the particle, and the time of chain-breaking is small as compared with the average time interval of successive absorption of radicals by the particle. The authors believe that case 2 corresponds to the emulsion polymerization of styrene in the presence of potassium persulfate [5]. The rate of formation of primary radicals is equal to 10 13 radicals• ml -1 s -1 . The average number of polymer particles is of the order of 10 14 -10 16 in 1 ml of the system. If all the radicals formed by the decay of the initiator enter the polymer particles, the average frequency at which a radical enters a particle is once per 10 -100 sec. At any time, the particle contains either one radical or does not contain radicals at all, since it is assumed that chain termination occurs immediately in contact with the second radical in the particle. The particle is inactive unt...

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Polymermonomer and polymerpolymer interactions and their effect on the stability of emulsifier-free acrylate latexes

Асламазова

Bogdanova

1995

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Emulsion polymerisation in the absence of an emulsifying agent and latexes based on it

Cited by 10 publications

References 1 publication

On the colloidal stability of polystyrene particles prepared with different kinds of surface active initiators

On the colloidal stability of polystyrene particles prepared with different kinds of surface active initiators

An Advanced Approach on the Study of Emulsion Polymerization: Effect of the Initial Dispersion State of the System on the Reaction Mechanism, Polymerization Rate, and Size Distribution of Polymer-Monomer Particles

Polymermonomer and polymerpolymer interactions and their effect on the stability of emulsifier-free acrylate latexes

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