A mathematical model of dispersion radical polymerization kinetics

Chernyshev, Andrei V.; Soini, Aleksi E.; Surovtsev, Ivan V.; Maltsev, Valeri P.

doi:10.1002/(sici)1099-0518(19970715)35:9<1799::aid-pola20>3.0.co;2-#

Cited by 17 publications

(16 citation statements)

References 15 publications

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“…It has been reported that in systems in which the polymer precipitates from the solution by the creation of a heterogeneous gel system, the increase of viscosity takes place very rapidly even at low conversions (Chapiro 1962). This effect has also been illustrated through mathematical models of dispersion radical polymerization kinetics (Chernyshev et al 1997). The lower termination rate may also be responsible for the increasing size of the polymer microgels with increasing dose, as has been observed by optical turbidity spectra (Maryanski et al 1996).…”

Section: Fundamental Principles Of Polymer Gel Dosimetrymentioning

confidence: 99%

Polymer gel dosimetry

et al. 2010

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Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented.

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Section: Fundamental Principles Of Polymer Gel Dosimetrymentioning

confidence: 99%

Polymer gel dosimetry

et al. 2010

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“…In fact, the reaction locus during a dispersion polymerization is so important that existing kinetic models can be roughly classified according to it. In this regard, the study of the polymerization locus and the kinetics of the polymerization through mathematical modeling have shown to be a useful tool to interpret experimental trends and to control the final properties of the polymer [19–29].…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical study of the reaction locus during the dispersion polymerization of methyl methacrylate in a nonpolar hydrocarbon solvent at low temperature

Emdadi

Luciani

Lee

et al. 2011

Polymer Engineering & Sci

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The dispersion polymerization of methyl methacrylate (MMA) has been studied in a nonpolar hydrocarbon solvent at low temperature using N,N‐dimethylaniline (DMA) and lauroyl peroxide (LPO) as redox initiation system. To explain the heterogeneous kinetic characteristics of the polymerization process, the reaction locus has been experimentally and theoretically investigated. The evolutions of monomer conversion, polymer molecular weight distribution (MWD), and particle morphology were measured throughout the polymerization. It was found that the significant preferences of LPO and DMA to accumulate in the polymer‐rich phase after the system phase separation are mainly responsible for both the uniformity of particle sizes and the broad polymer MWDs. It was observed that particle agglomeration and breakup mechanisms were enhanced under agitation, thus promoting the formation of broader particle size distributions. The observed kinetics and thermodynamics of the low‐temperature polymerization were also examined through a mathematical model where the distributions of initiators, solvent, and monomer between phases were considered. A good agreement between the experimental and theoretical results was observed and the model was used to estimate the conditions that promote bimodal MWDs. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

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“…In the precipitation and dispersion polymerization, there are four theories (model) for loci of polymerization reactions; solution polymerization model (all of the polymerization reactions take place in the continuous phase) [3][4][5][6][7], surface polymerization model (initiation take place in the continuous phase but propagation and termination occurs in the thin layer on the surface of the polymer particles) [8,9], interior polymerization model (initiation take place in the continuous phase but propagation and termination occur in the polymer particles) [10][11][12][13], and simultaneous polymerization model (polymerization reactions are able to occur simultaneously in the both dispersed and continuous phases) [14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Modeling of precipitation polymerization II: calculation of macroradicals concentrations in the continuous and dispersed phases

2011

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According to Hunkeler model, precipitation polymerization of acrylic acid in organic media takes place simultaneously in the both dispersed and continuous phases. In this research, a model is presented based on mass balances of individual species. Hence, concentrations of macroradicals and polymer chains, in different chain lengths, were calculated in the both phases. Number-and weightaverage degrees of polymerization and their distributions were concluded in the both dispersed and continuous phases. Calculation of macroradicals concentration was conducted with quasi-steady state approximation (QSSA) as well as without QSSA (based on the governing differential equations). Macroradical precipitate as soon as reaching to critical chain length. Moreover, precipitation is the main termination reaction in the continuous phase. Polymer with critical chain length is the most populated species in the dispersed phase. Comparison of theoretical and experimental results is in good agreement. QSSA theory gives better results than without QSSA theory because occlusion of macroradicals in the dispersed phase does not occur in the precipitation polymerization of water-soluble monomers in the organic media. This article has proved that the polydispersity index (PDI) of polymer product in the precipitation polymerization of acrylic acid in toluene that follows simultaneous polymerization model is less than that of PDI in the other free radical polymerization methods. Centrifugation method was used to sediment fine polymer particles. The yield of reaction was increased by sedimentation process.

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A mathematical model of dispersion radical polymerization kinetics

Cited by 17 publications

References 15 publications

Polymer gel dosimetry

Polymer gel dosimetry

Experimental and theoretical study of the reaction locus during the dispersion polymerization of methyl methacrylate in a nonpolar hydrocarbon solvent at low temperature

Modeling of precipitation polymerization II: calculation of macroradicals concentrations in the continuous and dispersed phases

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