Influence of agitation on the creation of coagulum during the emulsion polymerization of the system styrene–butylacrylate–acrylic acid

Matějíček, Alois; Pivoňková, Alena; Kaška, Jiří; Ditl, Pavel; Formánek, Leopold

doi:10.1002/app.1988.070350303

Cited by 17 publications

(6 citation statements)

References 6 publications

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“…Of course numerous experimental and theoretical studies have also been presented in the literature to improve the understanding of mechanisms that may influence particle nucleation3, 6–8 and coagulation 9‐13. In the earliest works on particle nucleation, the studies are based on assumptions that are not completely true.…”

Section: Introductionmentioning

confidence: 99%

Modeling the nucleation stage during batch emulsion polymerization

Fortuny¹,

Graillat²,

McKenna³

et al. 2005

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com). AIChE J, 51: 2521AIChE J, 51: -2533AIChE J, 51: , 2005 A model based on independently validated stabilization and rate data is used to quantify the rate of formation of particles during the dynamic nucleation stage of a batch emulsion polymerization reaction. Population balance equations (PBEs) that combine kinetic data validated in the absence of coagulation and a DLVO stability model with parameters validated in the absence of reaction were used to account for both micellar and homogeneous nucleation, as well as particle stabilization and growth. The model was tested in different polymerization systems at different ionic strengths. It is shown that a large number of moderately short-lived particles are formed during the early stages of nucleation and that they contribute to an accelerated rate of polymerization for a short period of time before coagulating onto large structures in the reactor. © 2005 American Institute of Chemical Engineers Keywords: particle size distribution (PSD), emulsion polymerization, nucleation, electrosteric surfactant, modeling IntroductionParticle nucleation is perhaps the most controversial aspect of emulsion polymerization reactions. The formation of the initial particles occurs very quickly, and different mechanisms must be simultaneously taken into account. [1][2][3] The experimental study of the nucleation stage is a difficult task because of the complexity and rapidity of the phenomena involved, as well as technical limits on the measurement of particle size distributions (PSDs) and the in-line/real-time monitoring of particle formation. Recent studies based on the development of conductivity sensors for the on-line monitoring of surfactant concentrations during emulsion polymerizations 4 indicate that conductivity data can provide useful information about the particle nucleation stage and provide direct quantitative evidence of what has long been postulated theoretically (such as coagulative nucleation theory 5 ): the profile of particle generation (that is, the evolution of the number of particles as a function of time) is not monotonically increasing, and that a large number of primary particles are formed in a short period of time and these particles coagulate to form the basis of the final particle population.Of course numerous experimental and theoretical studies have also been presented in the literature to improve the understanding of mechanisms that may influence particle nucleation 3,6-8 and coagulation. [9][10][11][12][13] In the earliest works on particle nucleation, the studies are based on assumptions that are not completely true. For instance, three of the most common ideas Present address of M. Fortuny: Instituto de Tecnologia e Pesquisa (ITP), Universidade Tiradentes (UNIT), Aracaju, Brazil.Correspondence concerning this article should be addressed to T. F. McKenna at mckenna@cpe.fr. were that (1) particle nucleation terminates at the end of interval I if the monomers are not particularly water soluble (th...

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Section: Introductionmentioning

confidence: 99%

Modeling the nucleation stage during batch emulsion polymerization

Fortuny¹,

Graillat²,

McKenna³

et al. 2005

AIChE Journal

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“…It was suggested that a = 1.0 and m = 0.65 provided the best fit to the corresponding experimental data. [45] The values of η 0 and η ∞ can be estimated from Equations (27) and (28) [46] :…”

Section: Rheology Modellingmentioning

confidence: 99%

“…[2,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Some other studies attempted to deal with the orthokinetic coagulation in a semi-empirical manner. [24][25][26][27] All these works were based on the assumption of perfect mixing within coagulators, in which spatially averaged coagulant concentrations and shear rates were adopted. However, in reality, the coagulant concentration and shear rate vary spatially in a coagulator, especially in a pilot or largescale coagulator.…”

Section: Introductionmentioning

confidence: 99%

Modelling study of emulsion latex coagulation processes in coagulators

2020

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This paper presents a numerical study of emulsion latex coagulation processes in continuous coagulators based on the full computational fluid dynamics approach. The RANS approach together with the k-ε turbulence model was used to describe the detailed flow field in the coagulators. The coagulant mixing process was modelled by the convection-diffusion equation and the emulsion latex coagulation process was formulated by the population balance equation of the particle size with a coagulation kernel including a perikinetic and orthokinetic combined mechanism. The flow and coagulation models were independently validated by means of comparing simulated results to the relevant experimental data from the literature. A series of simulations were carried out to study the effects of coagulator bottom shape, salt solution feeding location, residence time and agitation speed, as well as the influence of four typical scale-up criteria on the latex particle coagulation process. The presented results would be helpful for the relevant process design, development, and scale-up of continuous latex coagulators.

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“…Unfortunately, this is not an easy task since coagulum may be formed by different mechanisms [78], and the available models are essentially semi-empirical [79][80][81][82].…”

Section: Coagulation Mechanismsmentioning

confidence: 99%

Modeling particle size distribution in emulsion polymerization reactors

Vale

McKenna

2005

Progress in Polymer Science

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A review of the use and limitations of Population Balance Equations (PBE) in the modeling of emulsion polymerisation (EP), and in particular of the particle size distribution of the dispersed system is presented. After looking at the construction of the general form of PBEs for EP, a discussion of the different approaches used to model polymerization kinetics is presented. Following this, specific applications are presented in terms of developing a two-dimensional PBE for the modeling of more complex situations (for example the particle size distribution, PSD, and the composition of polymerizing particles). This review demonstrates that while the PBE approach to modeling EP is potentially very useful, certain problems remain to be solved, notably: the need to make simplifying assumptions about the distribution of free radicals in the particles in order to limit the computation complexity of the models; and the reliance of full models on approximate coagulation models. The review finishes by considering the different numerical techniques used to solve PBEs.

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Influence of agitation on the creation of coagulum during the emulsion polymerization of the system styrene–butylacrylate–acrylic acid

Cited by 17 publications

References 6 publications

Modeling the nucleation stage during batch emulsion polymerization

Modeling the nucleation stage during batch emulsion polymerization

Modelling study of emulsion latex coagulation processes in coagulators

Modeling particle size distribution in emulsion polymerization reactors

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