Online‐Reaktionsverfolgung bei der Polymerisation

Hergeth, Wolf‐Dieter; Frauendorfer, Eric

doi:10.1002/cite.200900132

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…To access the mean particle size in high-solid-content polymer dispersions and to determine the PSD, different techniques are known and promoted like turbidimetry, fiberoptic quasi-elastic light scattering or focused beam reflectance measurement, and particle vision and measurement technology. Online measurements in undiluted processes are particularly challenging due to the high turbidity, high number of particles, and multiple scattering [6][7][8][9][10][11]. Most commonly, offline PSD analysis is used.…”

Section: Introductionmentioning

confidence: 99%

Advanced Particle Size Analysis in High-Solid-Content Polymer Dispersions Using Photon Density Wave Spectroscopy

et al. 2023

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High-solid-content polystyrene and polyvinyl acetate dispersions of polymer particles with a 50 nm to 500 nm mean particle diameter and 12–55% (w/w) solid content have been produced via emulsion polymerization and characterized regarding their optical and physical properties. Both systems have been analyzed with common particle-size-measuring techniques like dynamic light scattering (DLS) and static light scattering (SLS) and compared to inline particle size distribution (PSD) measurements via photon density wave (PDW) spectroscopy in undiluted samples. It is shown that particle size measurements of undiluted polystyrene dispersions are in good agreement between analysis methods. However, for polyvinyl acetate particles, size determination is challenging due to bound water in the produced polymer. For the first time, water-swelling factors were determined via an iterative approach of PDW spectroscopy error (Χ2) minimization. It is shown that water-swollen particles can be analyzed in high-solid-content solutions and their physical properties can be assumed to determine the refractive index, density, and volume fraction in dispersion. It was found that assumed water swelling improved the reduced scattering coefficient fit by PDW spectroscopy by up to ten times and particle size determination was refined and enabled. Particle size analysis of the water-swollen particles agreed well with offline-based state-of-the-art techniques.

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Section: Introductionmentioning

confidence: 99%

Advanced Particle Size Analysis in High-Solid-Content Polymer Dispersions Using Photon Density Wave Spectroscopy

et al. 2023

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Online Model‐Based Process Safety Concepts in Polymerization

Manders

Meister

Bausa

et al. 2011

Macromolecular Symposia

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Summary: To safeguard runaway reactions in industrial scale, qualified methods have to be used. While mechanical safety devices are usually installed, their design may be problematic as the runaway kinetics must be known. This may not be the case for many processes due to the required flexibility and possible unanticipated deviations from recipes. It is shown that runaway kinetics can be very fast and can lead to high conversions. Therefore, a method is proposed that does not depend on kinetics but limits the amounts of unreacted monomer in the reactor by monitoring the conversion and by quantitatively determining the hazardous potential. If a potential violation is observed, feeds to the reactor are interrupted.

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