In-Line Monitoring of SBR Emulsion Polymerization Using ATR-FTIR Spectroscopy

The copolymerization of styrene/1,3-butadiene in emulsion was monitored in-line using an ATR-FTIR spectroscopic probe. The concentration of monomers was monitored to provide real-time conversion and copolymer composition data. Traditional off-line techniques, gravimetry and H-1-NMR spectroscopy, were compared to the in-line ATR-FTIR data. A multivariate calibration method using the full reaction spectra displayed no significant differences between the off-line and in-line data sets at a 95% confidence level. It was demonstrated that ATR-FTIR spectroscopy is a reliable tool for monitoring conversion and polymer composition in multi-phase emulsion polymerizations.