Inline monitoring of styrene/butyl acrylate miniemulsion polymerization with attenuated total reflectance/Fourier transform infrared spectroscopy

Abstract

The copolymerization of styrene/butyl acrylate in a miniemulsion was monitored inline with an attenuated total reflectance/Fourier transform infrared (ATR-FTIR) probe. ATR-FTIR spectroscopy was used to track the concentration of the monomers, thereby providing conversion and polymer composition data. Offline gravimetry and 1 H-NMR spectroscopy were used to provide a comparison with the ATR-FTIR data. Because of inconsistent results with a univariate method, a multivariate or partial least squares calibration method using the full spectra of the reactions was selected and gave excellent results. No statistically significant differences were found between the offline and ATR-FTIR spectroscopy data coupled with multivariate statistics, and this confirmed that ATR-FTIR spectroscopy is a reliable tool for monitoring the conversion and polymer composition in miniemulsion polymerizations.

Reaction Monitoring of Glycerol Step‐Growth Polymerization Using ATR‐FTIR Spectroscopy

“…A main disadvantage of common off‐line characterization methods, such as NMR spectroscopy and wet‐chemical methods is the time lag between the result and sampling. Although these methods are accurate, they are often tedious, time consuming and not environmentally friendly 2. On the other hand most real‐time methods are cost‐effective, non‐destructive, and have no negative effect on our environment.…”

Polymerization Online Monitoring

“…These probes also eliminate the necessity of sample preparation. For example, Dubé shows the inline monitoring of a St/BA miniemulsion using FTIR-ATR in [62] and the monitoring of a butyl acrylate/MMA/vinyl acetate solution-terpolymerization process in [63].…”

A Critical Overview of Sensors for Monitoring Polymerizations

“…They also noted that ATR‐FTIR spectroscopy was capable to follow induction periods successfully as well as providing an indication of coagulation events. Rivard395 and Roberge and Dube396 described the application of in‐line ATR‐FTIR in the solution and mini‐emulsion polymerization of STY/BA, respectively. They estimated conversion using both univariate and multivariate methods and then compared those results with off‐line gravimetry.…”

“…Different multivariate statistical approaches have been used in combination with on‐line sensors for calibration purposes such as in IR and Raman spectroscopy (see Sections 3.9.3 and 3.9.5). For instance, in the realm of Near‐ and Mid‐IR spectroscopy, Sasic et al,591 Reshadat and Balke,437 Reshadat et al,242, 250 Apruzzese et al,238 Stavropoulos et al,397 Roberge and Dube396 and Watari and Ozaki413, 592 performed calibrations using multivariate approaches. In Raman spectroscopy, Vickers et al,593 van den Brink,482 van den Brink et al,483–486 Aust et al224 and Reis et al224, 430, 436, 493, 594 have also used these approaches.…”