FT-IR spectroscopy applied to the study of the curing process of epoxy-amine systems: a literature review

Epoxy resins find wide applications in many fields and have been extensively studied. In particular, great effort has been devoted to the study of the mechanism of crosslinking reactions analysing the factors affecting the molecular network and the physical properties of the hardened material. A detailed understanding of the "curing process" and of the structure-properties relationship, in fact, is essential to control and optimise the process parameters in order to tailor the performance of the of cured systems. Different analytical techniques have been employed to this aim. Among them, FTIR (Fourier transform infrared) spectroscopy has proved to be very helpful allowing quantitative measurements of the variations of functional groups during the crosslinking reactions. In the present work, a review of the scientific publications dealing with the application of FTIR to study the mechanism and the kinetic of the "curing process" of epoxy resins hardened with amines, is presented. This kind of formulation, in fact, is one of the most frequently used and, therefore, has been extensively studied. The main characteristic absorbance peaks of epoxy-amine systems have been listed and discussed. Finally, the kinetic equations more widely employed to determine the degree of conversion and the kinetic parameters, have been reported.