Industrial application of Raman spectroscopy for control and optimization of vinyl acetate resin polymerization.

Monitoring and control of resin polymerizations is essential for high process safety, high product quality, and competitive production costs. Vinyl acetate resins created by bulk and solution polymerization usually have a high molecular weight and viscosity, making sample extraction for analysis a cumbersome process. In-process analytical methods, like Raman spectroscopy, enable not only the measurement of monomer and polymer composition during the reaction without complex mathematical calibrations but also the determination of final product properties. The latter is also possible in conjunction with other process data like temperatures and feed rates and with a multivariate approach. An overview of challenges, necessary considerations, and results is given. Graphical abstract Prediction of product quality parameter viscosity using online-Raman spectroscopy data vs. reference data (Hoeppler viscosity measured in the lab after sample extraction) using partial least squares modelling.