Real-time analysis of the polymerization kinetics of 1,4-butanediol and 4,4'-diphenylmethanediisocyanate by fiber-coupled Fourier transform infrared spectroscopy

Polyurethanes are a polymer class with large property diversity. However, despite their extreme technical importance, only few research data regarding the on-line analysis and the derivation of kinetic polymerization data are available in the literature. The present work focuses on the in-line monitoring of the solution polymerization of 4,4'-diphenylmethanediisocyanate and 1,4-butanediol by fiber-coupled FT-IR spectroscopy in the attenuated total reflection (ATR) mode at variable temperatures and the interpretation of the spectral changes as a function of polymerization progress. Furthermore, the activation energy of the solution polymerization will be derived from the kinetic data and experimental issues of the ATR in-line measurement mode will be addressed.