Coagulation of Anionically Stabilized Polymer Particles

Fortuny, Montserrat; Graillat, and Christian; McKenna, Timothy F. L.

doi:10.1021/ie0342917

Cited by 28 publications

(39 citation statements)

References 23 publications

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“…This eliminates the particle nucleation and particle growth via polymerization terms from the population balance equation (PBE), but is still reflective of common polymerization processes such as those outlined in Fortuny et al [24] and Konstansek [22]. The multizonal model is comprised of a series of interconnected, well-mixed zones, thus eliminating the need to define an external coordinate domain.…”

Section: Population Balancementioning

confidence: 99%

Development of a Computational Framework to Model the Scale‐up of High‐Solid‐Content Polymer Latex Reactors

Pohn

Heniche²,

Fradette³

et al. 2010

Chem Eng & Technol

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A computational framework, consisting of a laminar computational fluid dynamics (CFD) simulation model coupled to a multizonal population balance, is developed to assist in the scale-up of high-solid-content (HSC) latex production and processing. Poly3D CFD software is used to generate flow fields inside a series of reactors; this information is then sent to the process model to assess the impact of nonhomogeneous mixing on the evolution of the latex particle size distribution (PSD) when concentrated latex suspension is altered via the addition of a coagulant. As the general shape of the PSD evolves, the model monitors changes in the rheological parameters in each zone of the reactor; the flow field is recomputed if a significant change in any of the properties is detected. The details of the framework are presented and its utility is demonstrated. Preliminary results indicate that nonhomogeneity inside the reactor will have an effect on the final latex PSD obtained.

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Section: Population Balancementioning

confidence: 99%

Development of a Computational Framework to Model the Scale‐up of High‐Solid‐Content Polymer Latex Reactors

Pohn

Heniche²,

Fradette³

et al. 2010

Chem Eng & Technol

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“…A number of models based on the (classical and extended) DLVO theory [83,84] have been proposed to predict the coagulation rate coefficients of latex particles stabilized both by anionic surfactants (Coen et al [8,22], Fortuny et al [85], Kiparissides et al [86], and Melis et al [87,88]), or of non-ionic surfactants (Immanuel et al [13], Kammona et al [48], and Lazaridis [89]). Next, we will take a look at the key steps of the DLVO approach, followed by a discussion of its major limitations.…”

Section: Dlvo-based Modelsmentioning

confidence: 99%

“…This equation was used in references [13,48,85,[87][88][89] assuming G=1, i.e. neglecting the hydrodynamic interaction.…”

Section: Overview Of the Dlvo Approachmentioning

confidence: 99%

“…A number of authors [85,86,89] followed the approach given by Coen et al [8] and used the Debye-Huckel or the Gouy-Chapman equations to relate 0 σ to the surface potential 0 ψ , and then a Stern layer model to compute d ψ from 0 ψ . However, as noted by Melis et al [88], such a procedure seems to be incorrect since the Debye-Huckel and Gouy-Chapman equations cannot be used to relate 0 σ to the surface potential 0 ψ .…”

Section: Overview Of the Dlvo Approachmentioning

confidence: 99%

“…In the first instance, the obvious way to go around this interdependency problem would be to test the coagulation model under non-reacting conditions, as done by Melis et al [88] and Fortuny et al [85]. For example, the model could be compared with experimental data for the coagulation of monomer swollen particles or with experimental values of the stability ratio (obtained by turbidimetry, dynamic light scattering, etc.…”

Section: Experimental Validationmentioning

confidence: 99%

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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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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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Coagulation of Anionically Stabilized Polymer Particles

Cited by 28 publications

References 23 publications

Development of a Computational Framework to Model the Scale‐up of High‐Solid‐Content Polymer Latex Reactors

Development of a Computational Framework to Model the Scale‐up of High‐Solid‐Content Polymer Latex Reactors

Modeling particle size distribution in emulsion polymerization reactors

Modeling the nucleation stage during batch emulsion polymerization

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