Characterization of Polyurethane Foams by Mid-Infrared Fiber/FT-IR Spectrometry

Abstract

The use of a mid-infrared transmitting fiber to monitor the cure process of a polyurethane foam is described. A chalcogenide fiber was situated between the spectrometer and a remote detector, but passed through the center of a polyurethane foam. This fiber was used as an internal reflectance element to observe changes in the polyurethane curing process. The appearance and disappearance of absorbances in the NH-stretching, carbonyl stretching (free urea and urethane, hydrogen-bonded urethane, and monodentate and bidentate hydrogen-bonded urea), isocyanate, and isocyanurate regions were monitored. These changes provided information about the reaction kinetics and morphological development of the foam.