Diffusion in polymer-solvent systems

Chalykh, A.Ye.; Vasenin, R.M.

doi:10.1016/0032-3950(66)90126-2

Cited by 52 publications

(45 citation statements)

References 11 publications

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“…They are characterized by the general tendency for chang- ing the diffusion coefficients as the composition and temperature change. 1 In the limitedly compatible systems, the dependencies of D V on the content of a diffusant ( 1 ) change along smooth vortex curves and descend sharply near the binodal. 7 In the systems studied, D V undergo the maximum changes in the region of compositions close to the pure copolymer.…”

Section: Resultsmentioning

confidence: 98%

Mutual diffusion and phase equilibrium in copolymers of nonyl acrylate and acrylic acid-diglycidyl ether of bisphenol A systems

Mikhailov

Ganina

Makhonina

et al. 1999

J. Appl. Polym. Sci.

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ABSTRACT:The influence of the composition of statistical copolymers of nonyl acrylate with acrylic acid on the rate of mass transfer and phase equilibrium in solutions with diglycidyl ether of bisphenol A was studied. For these systems, the data on concentration dependencies of mutual diffusion coefficients and phase diagrams were obtained. The results were interpreted on the basis of the assumption about the effect of the effective concentration of nodes of the network of hydrogen bonds on the mutual diffusion and phase equilibrium. The dependencies of the mutual diffusion coefficients on the content of acrylic acid in the copolymers are described in terms of the free volume theory.

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Section: Resultsmentioning

confidence: 98%

Mutual diffusion and phase equilibrium in copolymers of nonyl acrylate and acrylic acid-diglycidyl ether of bisphenol A systems

Mikhailov

Ganina

Makhonina

et al. 1999

J. Appl. Polym. Sci.

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“…A significant attention in the literature was devoted to the investigation of the properties of microemulsions (ME) and conditions of their formation [81][82][83][84][85][86][87][88][89][90][91][92][93][94], however, the thermodynamic equilibrium of lyophilic systems [81,82] was mainly considered.…”

Section: Mechanism Of Particle Formation From Microdroplets Of Monomermentioning

confidence: 99%

“…As a result, only part of the dispersed phase the in the layer adjacent to the interface can be involved in emulsification [91][92][93][94].…”

Section: Mechanism Of Particle Formation From Microdroplets Of Monomermentioning

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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“…According to this approach, the mobility of molecules in binary systems is characterised by the partial selfdiffusion coefficients of the solvent molecules (in the present case, water) and the molecules of dissolved substance (glucose). The fluxes of molecules of the solvent and the dissolved substance interact with each other, and the corresponding diffusion coefficients are coupled via the interdiffusion coefficients [22]. Unfortunately, at present, there are no reliable methods for separate measurement of these coefficients, or they can be measured only in rare particular cases.…”

Section: Methodsmentioning

confidence: 99%

“…The interstitial matrix of fibrous tissues can be presented as a polyelectrolyte gel [19][20][21]. Hence, the diffusion process can be described using the well-developed technique of physical and colloid chemistry [22]. According to this approach, the mobility of molecules in binary systems is characterised by the partial selfdiffusion coefficients of the solvent molecules (in the present case, water) and the molecules of dissolved substance (glucose).…”

Section: Methodsmentioning

confidence: 99%

Optical clearing of human dura mater by glucose solutions

Genina

Bashkatov

Tuchin

2017

JBPE

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Abstract. Significant light scattering by dura mater in the visible spectral range seriously restricts the application of noninvasive optical methods to the diagnostics and therapy of brain diseases. We present the results of the study of human dura mater optical clearing in vitro by the glucose solutions with the concentrations 1.5М and 3М in the spectral range 400-700 nm. The efficiency of the tissue optical clearing is assessed. Basing on the analysis of the kinetics of collimated transmittance of light by samples of dura mater, the relative glucose diffusion coefficients are calculated that amount to (1.10.1)10 -6 cm 2 /s and (2.00.2)10 -6 cm 2 /s, respectively.

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Diffusion in polymer-solvent systems

Cited by 52 publications

References 11 publications

Mutual diffusion and phase equilibrium in copolymers of nonyl acrylate and acrylic acid-diglycidyl ether of bisphenol A systems

Mutual diffusion and phase equilibrium in copolymers of nonyl acrylate and acrylic acid-diglycidyl ether of bisphenol A systems

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

Optical clearing of human dura mater by glucose solutions

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