Reactor Concepts for Continuous Emulsion Polymerization

Pauer, Werner

doi:10.1007/12_2017_24

Cited by 6 publications

(4 citation statements)

References 103 publications

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“…[5] The high particle concentration with a high molecular weight and the temperature-sensitive characteristic of latex particles cause the concentration and temperature to be the major factors controlling particulate fouling during emulsion polymerization. [12,13] The fundamentals of reaction fouling are treated much more specifically. Depending on the reaction type, three types of reaction fouling may be distinguished: autoxidation, polymerization, and thermal decomposition.…”

Section: Introductionmentioning

confidence: 99%

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Polymer Versus Polymerization Fouling: Basic Deposition Mechanisms During Emulsion Polymerization by the Example of a Vinyl Acetate and Versa 10 Copolymer

Klinkert,

Friedrich,

Glatt

et al. 2024

Macro Reaction Engineering

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The deposition process during emulsion polymerization can be classified as both particulate and reaction fouling, but a deeper understanding of the deposition mechanism, especially in combination with the polymerization process, is lacking. Here, a more in‐depth understanding of the deposition mechanism was sought by investigating the fouling formation of a Vinyl acetate and Versa® 10 copolymer on a heated stainless steel surface during emulsion polymerization. Its deposition behavior was also compared with the behavior of an already reacted polymer. All possible influencing factors were investigated separately, and the fouling was quantified by the mass based fouling resistance and the fouling layer composition. The fouling rates of both experimental approaches (ongoing reaction versus already reacted polymer) were used to determine the fraction of reaction fouling along the reaction pathway. The solids content and the driving temperature difference were identified as the main factors influencing fouling formation. The deposited material was composed of latex particles and emulsifier with particle size and number depending on the respective equilibrium composition of the fluid phase. The reaction fouling rate was correlated with the proportion of free initiator radicals and the amount of dissolved monomer in the aqueous phase.This article is protected by copyright. All rights reserved

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Section: Introductionmentioning

confidence: 99%

“…[ 5 ] The high particle concentration with a high molecular weight and the temperature‐sensitive characteristic of latex particles cause the concentration and temperature to be the major factors controlling particulate fouling during emulsion polymerization. [ 12,13 ]…”

Section: Introductionmentioning

confidence: 99%

Polymer Versus Polymerization Fouling: Basic Deposition Mechanisms During Emulsion Polymerization by the Example of a Vinyl Acetate and Versa 10 Copolymer

Klinkert,

Friedrich,

Glatt

et al. 2024

Macro Reaction Engineering

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“…Emulsion polymerization is one of the most important processes for the production of waterborne latex polymers in industry. − It is typically carried out in a temperature range from 75 °C to 90 °C in order to achieve high space-time yields. Thermal initiators are commonly used in this temperature range providing an adequate radical generation rate. − The homolytic cleavage of covalent bonds of most practical thermal initiators requires a bond dissociation energy in the range of 125–160 kJ mol –1 .…”

Section: Introductionmentioning

confidence: 99%

Kinetic Description of Ascorbic Acid Decomposition in Redox Initiator Systems for Polymerization Processes

Schroeter

Bettermann

Semken

et al. 2019

Ind. Eng. Chem. Res.

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The temperature dependent redox decomposition rate constants of ascorbic acid (AsAc) in aqueous solutions were quantified in the presence of ammonium iron(III) sulfate dodecahydrate (Fe-cat) and tert-butylhydroperoxide (TBHP). Decomposition rates were determined in a temperature range from 35−75 °C with respect to the component ratios. First-order kinetics were observed up to specific conversions (∼20−80%) for AsAc decomposition. The application of a flexible Weibull model provided a good and comparable description (R 2 ≥ 0.992) of decomposition processes up to high AsAc conversions (96%) at all studied reaction conditions. The activation energy was determined as a function of AsAc and Fe-cat ratios (38−79 kJ mol −1 ). Statistical modeling facilitated the prediction of rate constants. Thus, it was possible to adjust the reaction rate of emulsion copolymerizations of vinyl acetate and Versa10 in a broad temperature range (10−70 °C) by variation of the Fe-cat content.

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“…Supported metallocene catalysts are used for the industrial-scale synthesis of polyethylene or isotactic polypropylene. Metallocene must be applied to support existing technical processes (drop-in technology) [34,42]. Several methods are shown in Figure 11 (A) Immobilized cocatalyst/support: Add MAO cocatalyst on the support first, followed by addition of the metallocene in the polymerization reactor that method is mostly used.…”

Section: Supported Metallocene Catalystsmentioning

confidence: 99%

Ethylene polymerization with zirconocene catalyston zeolite A support derived from fly ash

Warintha

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Zeolite A (LTA) synthesis from fly ash has many applications, in which metallocene catalytic support is uncommon. This research study has three parts. Firstly, investigation of the effects of immobilized MAO cocatalyst and zirconocene catalyst techniques on silica support. Immobilized MAO, followed by metallocene catalyst method had the highest catalytic activity, which was used in the next parts. The second part examined the optimal temperature and [Al]MAO/[Zr]cat ratio with ethylene polymerization in a semi-batch autoclave reactor utilizing LTA-supported metallocene catalysts. The optimal conditions were found at 80?C and [Al]MAO/[Zr]cat ratios equal to 2000 that were used in the next section. LTA-MAO/Zr showed lower catalytic activity than silica-supported catalysts. This is because acidity disrupted polymer chain formation and reduced crystallinity. Finally, a comparison of three zeolite supports for ethylene and ethylene/1-hexene polymerization was conducted. LTA-MAO/Zr had the best catalytic activities among ZSM5 and BEA support because of a higher Al/Zr ratio and Lewis acidity, which corresponded to the catalyst activity. However, we cannot generalize that high zeolite support acidity leads to high catalyst activity because it depends on multiple factors. Therefore, LTA was an optimally supported metallocene catalyst system.

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Reactor Concepts for Continuous Emulsion Polymerization

Cited by 6 publications

References 103 publications

Polymer Versus Polymerization Fouling: Basic Deposition Mechanisms During Emulsion Polymerization by the Example of a Vinyl Acetate and Versa 10 Copolymer

Polymer Versus Polymerization Fouling: Basic Deposition Mechanisms During Emulsion Polymerization by the Example of a Vinyl Acetate and Versa 10 Copolymer

Kinetic Description of Ascorbic Acid Decomposition in Redox Initiator Systems for Polymerization Processes

Ethylene polymerization with zirconocene catalyston zeolite A support derived from fly ash

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