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In‐Line Monitoring of Particle Size during Emulsion Polymerization under Different Operational Conditions using NIR Spectroscopy
Author(s) -
Chicoma Dennis L.,
Sayer Claudia,
Giudici Reinaldo
Publication year - 2011
Publication title -
macromolecular reaction engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 32
eISSN - 1862-8338
pISSN - 1862-832X
DOI - 10.1002/mren.201000049
Subject(s) - emulsion polymerization , absorbance , vinyl acetate , particle size , materials science , dynamic light scattering , polymer , butyl acrylate , emulsion , analytical chemistry (journal) , styrene , particle (ecology) , calibration , spectroscopy , polymerization , copolymer , polymer chemistry , chemical engineering , chemistry , chromatography , nanotechnology , organic chemistry , nanoparticle , composite material , mathematics , geology , oceanography , engineering , quantum mechanics , statistics , physics
In the present work, the sensitivity of NIR spectroscopy toward the evolution of particle size was studied during emulsion homopolymerization of styrene (Sty) and emulsion copolymerization of vinyl acetate–butyl acrylate conducted in a semibatch stirred tank and a tubular pulsed sieve plate reactor, respectively. All NIR spectra were collected online with a transflectance probe immersed into the reaction medium. The spectral range used for the NIR monitoring was from 9 500 to 13 000 cm −1 , where the absorbance of the chemical components present is minimal and the changes in the NIR spectrum can be ascribed to the effects of light scattering by the polymer particles. Off‐line measurements of the average diameter of the polymer particles by DLS were used as reference values for the development of the multivariate NIR calibration models based on partial least squares. Results indicated that, in the spectral range studied, it is possible to monitor the evolution of the average size of the polymer particles during emulsion polymerization reactions. The inclusion of an additional spectral range, from 5 701 to 6 447 cm −1 , containing information on absorbances (“chemical information”) in the calibration models was also evaluated.