An overview of high temperature micro-ATR IR spectroscopy to monitor polymer reactions

High temperature micro-ATR IR spectroscopy has recently become available, allowing for convenient IR spectral acquisition at elevated temperatures. This study presents a perspective on using this capability to monitor polymer chemistry with an emphasis on the study of polymer cure reactions. Examples are provided to demonstrate how easily time-resolved data can be acquired at temperatures of up to 200 °C. IR signatures of the key reactions and basic cure kinetics are compared for a few specific resin systems, ranging from amine- and anhydride-cured epoxies, to benzoxazine, cyanate ester or polyurea cure. This approach allows an evaluation of cure chemistry and kinetics as a function of temperature, resin constituents, or catalyst addition. Similarly, in-situ thermo-oxidative degradation can be monitored, as shown for a thin film of solvent deposited hydroxyl-terminated polybutadiene. In conclusion, high temperature IR is very attractive for resin cure and composite material characterization or aspects of polymer degradation, wherever infrared spectral changes are involved as part of reactive chemistry.