Advanced Particle Size Analysis in High-Solid-Content Polymer Dispersions Using Photon Density Wave Spectroscopy.
Stephanie Schlappa1, Lena Bressel1, Oliver Reich2
1Department of Physical Chemistry, innoFSPEC, University of Potsdam, Am Mühlenberg 3, 14476 Potsdam, Germany.
Polymers
|August 12, 2023
Summary
High-solid-content polymer dispersions were analyzed using photon density wave (PDW) spectroscopy. This method accurately determined particle sizes, even for challenging polyvinyl acetate, by accounting for water swelling.
Area of Science:
- Polymer Science
- Materials Science
- Physical Chemistry
Background:
- High-solid-content polymer dispersions are crucial in various industrial applications.
- Accurate characterization of particle size distribution (PSD) is essential for predicting material properties.
- Traditional particle sizing techniques face challenges with certain polymer systems, like polyvinyl acetate, due to bound water.
Purpose of the Study:
- To produce and characterize high-solid-content polystyrene (PS) and polyvinyl acetate (PVAc) dispersions.
- To compare inline photon density wave (PDW) spectroscopy with offline methods (DLS, SLS) for PSD analysis.
- To develop a method for accurate particle size determination of water-swollen PVAc particles in concentrated dispersions.
Main Methods:
- Emulsion polymerization was used to synthesize PS and PVAc particles (50-500 nm diameter).
- Particle size distribution was measured using dynamic light scattering (DLS), static light scattering (SLS), and inline photon density wave (PDW) spectroscopy.
- An iterative approach minimizing PDW spectroscopy error (Χ²) was employed to determine water-swelling factors for PVAc particles.
Main Results:
- Inline PDW spectroscopy showed good agreement with DLS and SLS for undiluted PS dispersions.
- Particle size determination for PVAc dispersions was challenging due to bound water, but improved significantly by accounting for swelling.
- The water-swelling factors enabled accurate analysis of physical properties (refractive index, density, volume fraction) and improved PDW fits by up to tenfold.
- PDW analysis of water-swollen PVAc particles correlated well with offline techniques.
Conclusions:
- Photon density wave (PDW) spectroscopy is a viable inline technique for characterizing high-solid-content polymer dispersions.
- Accounting for water swelling is critical for accurate particle size analysis of polymers like PVAc.
- The developed method refines particle size determination and enables characterization of challenging polymer systems in concentrated solutions.
