TY  - JOUR
A1  - Schlappa, Stephanie
A1  - Brenker, Lee Josephine
A1  - Bressel, Lena
A1  - Hass, Roland
A1  - Münzberg, Marvin
T1  - Process characterization of polyvinyl acetate emulsions applying inline photon density wave spectroscopy at high solid contents
JF  - Polymers / Molecular Diversity Preservation International
N2  - The high solids semicontinuous emulsion polymerization of polyvinyl acetate using poly (vinyl alcohol-co-vinyl acetate) as protective colloid is investigated by optical spectroscopy. The suitability of Photon Density Wave (PDW) spectroscopy as inline Process Analytical Technology (PAT) for emulsion polymerization processes at high solid contents (>40% (w/w)) is studied and evaluated. Inline data on absorption and scattering in the dispersion is obtained in real-time. The radical polymerization of vinyl acetate to polyvinyl acetate using ascorbic acid and sodium persulfate as redox initiator system and poly (vinyl alcohol-co-vinyl acetate) as protective colloid is investigated. Starved-feed radical emulsion polymerization yielded particle sizes in the nanometer size regime. PDW spectroscopy is used to monitor the progress of polymerization by studying the absorption and scattering properties during the synthesis of dispersions with increasing monomer amount and correspondingly decreasing feed rate of protective colloid. Results are compared to particle sizes determined with offline dynamic light scattering (DLS) and static light scattering (SLS) during the synthesis.
KW  - photon density wave spectroscopy
KW  - multiple light scattering
KW  - emulsion
KW  - polymerization
KW  - process analytical technology
KW  - polyvinyl acetate
Y1  - 2021
U6  - https://doi.org/10.3390/polym13040669
SN  - 2073-4360
VL  - 13
IS  - 4
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Hass, Roland
A1  - Reich, Oliver
T1  - Photon density wave spectroscopy for dilution-free sizing of highly concentrated nanoparticles during starved-feed polymerization
JF  - ChemPhysChem : a European journal of chemical physics and physical chemistry
KW  - analytical methods
KW  - fiber-optical spectroscopy
KW  - nanoparticles
KW  - photon density wave spectroscopy
KW  - polymerization
Y1  - 2011
U6  - https://doi.org/10.1002/cphc.201100323
SN  - 1439-4235
VL  - 12
IS  - 14
SP  - 2572
EP  - 2575
PB  - Wiley-Blackwell
CY  - Malden
ER  -