Styrene Drop Size and Size Distribution in an Aqueous Solution of Poly(vinyl alcohol)

Yang, Bin; Takahashi, Koji; Takeishi, Makoto

doi:10.1021/ie990709i

Cited by 22 publications

(30 citation statements)

References 11 publications

(12 reference statements)

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“…In liquid‐liquid dispersions drop size distribution becomes narrower and shifts towards smaller size range with an increase in the agitation rate . An increase in the agitation rate increased the rate of drop break up and thus favours the formation of smaller drops . It is also reported that the Sauter mean diameter decreases with increasing in the agitation rates when the stabilizer concentration kept constant as expected .…”

Section: Resultssupporting

confidence: 58%

Tailoring the Particle Size Distribution in Suspension Polymerization of Poly(MMA‐co‐EGDMA): Role of Stabilizer and Agitation Rate

Sharma

Khan

Thakur

et al. 2017

Macromolecular Symposia

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In suspension polymerization, the particle size distribution plays important role since it determines the application and process ability of final product. However, the particle size distribution (PSD) can be controlled by varying operating parameters and this can improve the quality of final product. Herein, the present work focuses on role of stabilizer concentration and agitation speed on controlling PSD in suspension polymerization of crosslinked porous poly(methylmethacrylate‐co‐ethyleneglycoldimethacrylate) p(MMA‐co‐EGDMA).By controlling these two parameters particle size distribution results in in the range of 500–841 μm which is desirable for various industrial applications. The percent yield of particles falling in the range of 500–841 μm was found 73 ± 1.0% at PVA concentration 2%w/v and at agitation rate of 220 rpm. The Sauter mean diameter has also been evaluated. As PVA concentration and agitation rate increased, mean drop size decreased and PSD became narrower which led to reducing the Sauter mean diameter. The experimental results reveal that by controlling only two parameters the desirable PSD could be obtained.

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Section: Resultssupporting

confidence: 58%

Tailoring the Particle Size Distribution in Suspension Polymerization of Poly(MMA‐co‐EGDMA): Role of Stabilizer and Agitation Rate

Sharma

Khan

Thakur

et al. 2017

Macromolecular Symposia

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“…Although a variety of surfactants exist, including low molecular weight cationic and anionic surfactants, PVA was chosen as a popular surfactant with common industrial use. It is known that the stabilizing abilities of a surfactant are dependent upon the degree of hydrolysis and molecular weight, both of which were kept constant for all experiments …”

Section: Resultsmentioning

confidence: 99%

Cross Linking Between the Baffling Effect and Phase Inversion During Liquid–Liquid Monomer Mixing

Cocke

Maaß

2017

Macro Reaction Engineering

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remains one of the most difficult and least understood mixing problems, in contempt of its major significance for optimization of suspension polymerization. The first step of the process, the liquid-liquid mixing and even more the medium conversion stage with increased dispersed phase viscosity and sticky polymer-monomer particles already determines the size of the final particle size distribution.Xie et al. are introducing this major challenge and give a meaningful introduction about suspension polymerization. [1] It has been widely used to produce poly-(vinyl chloride), poly-(vinylidene chloride) copolymers, polystyrene, poly-(methyl methacrylate), and high value-added polymer particulate products (e.g., chromatographic separation media, ion exchange resins, and enzyme immobilization supports). During the suspension polymerization process, a monomer (or monomers) that is immiscible or slightly soluble in water is first dispersed to form monomer droplets by stirring in the aqueous phase containing a dispersant-the liquid-liquid mixing process.Recent studies have revealed unexpected developments in drop size by only small changes in the geometrical constraints of batch vessels used for suspension polymerization. The effect of the dispersed phase fraction, surfactant concentration, as well as baffle length on the evolving drop size distribution in different low viscous liquid-liquid systems is investigated. The analysis is focused on the drop-dominated systems by hindering the coalescence by polyvinyl alcohol (PVA) concentrations up to three times higher than the critical micelle concentration. The influence of PVA on drop size in breakage-dominated systems is well reproduced with population balance equation simulations. The drops are measured using a photo-optical system with automated image analysis. The measured drop sizes increase with increasing dispersed phase fraction. As coalescence is completely hindered, all observed coalescence effects are connected to phase inversion, a catastrophic phenomenon during suspension polymerization for industrial production processes. Phase inversion can be reproduced for all studied solvents with and without the use of surfactants. In particular, the influence of the baffles can be reproduced. The system is adapted and trained to detect phase inversion as a warning system to make the suspension polymerization process more stable and robust.

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“…56 The stabilizing properties depend on the concentration of the stabilizer. 22 However, the stabilizer is more effective at low viscosity, and the influence of stabilizer concentration in lowering the surface tension decays when the viscosity of the drops increases. 16 In a study conducted by Tobin et al 47 a few drops of SDS solution were added to their sample in order to immobilize the drops.…”

Section: Comparisons Of Drop Size Measurement Betweenmentioning

confidence: 99%

“…The final particle size is determined by the drop size and drop size distribution during early stages of the suspension polymerization with the aid of suspending agents. 22 Liquid−liquid dispersion can be characterized by parameters which can represent the entire dispersion such as the median drop size; the Sauter mean diameter, d 32 ; and the diameter of the largest drop, d max . 23 d 32 is commonly used in characterization of liquid−liquid dispersion because it relates the area of the dispersed phase to its volume.…”

Section: Introductionmentioning

confidence: 99%

Review on Measurement Techniques for Drop Size Distribution in a Stirred Vessel

Abidin

Raman

Nor

2013

Ind. Eng. Chem. Res.

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A literature review on measurements of drop size distribution in liquid−liquid dispersion produced in a stirred vessel is presented in this work. The methods of measurement can be classified into in situ and external measurement. Two main groups of measurement techniques, namely, a laser system and image analysis, are reviewed. Several issues regarding the applications of the techniques and possible ways to overcome the problems are discussed. The suitability of different techniques depends on the operating conditions and properties of the drops. Laser systems provide fast in situ measurements which are useful for online monitoring and detecting process changes but unable to deliver reliable drop size and distribution values. In situ image analysis techniques could give accurate measurement of drop size, but a long time is required to analyze drops from a large number of images. However with development of automated image analysis, analysis time can be reduced. Therefore real-time monitoring and process control by image analysis techniques can be possible.

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Styrene Drop Size and Size Distribution in an Aqueous Solution of Poly(vinyl alcohol)

Cited by 22 publications

References 11 publications

Tailoring the Particle Size Distribution in Suspension Polymerization of Poly(MMA‐co‐EGDMA): Role of Stabilizer and Agitation Rate

Tailoring the Particle Size Distribution in Suspension Polymerization of Poly(MMA‐co‐EGDMA): Role of Stabilizer and Agitation Rate

Cross Linking Between the Baffling Effect and Phase Inversion During Liquid–Liquid Monomer Mixing

Review on Measurement Techniques for Drop Size Distribution in a Stirred Vessel

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