The amine-epoxy reaction is important in understanding the cure chemistry of a wide variety of epoxy based thermoset materials, where the extent of the amine-epoxy reaction is directly related to the evolution of the primary and secondary amine hydrogens and the formation of a hydroxyl group. FTIR spectroscopy can be used to monitor the amine hydrogens and hydroxyl; however, the FTIR spectra is complicated by the formation of hydrogen bonds, where both the amine hydrogens and the hydroxyl group can form various kinds of hydrogen bonds with the H-bond acceptors on both the reactants and the resulting polymer. Inorder to use FTIR spectra for the quantitative analysis of the amine-epoxy cure reaction, hydrogen bond formations were quantitatively analyzed for simple binary and ternary mixture of model amines (i.e. N-methyl aniline and aniline) with alkyl-alcohols and additional model compounds with H-bond acceptor agents (i.e. epoxide, ether, tertiary amine and phenyl groups which indicate p bond). The extensive FTIR spectra from 3200cm-1 to 3600 cm-1was quantitatively deconvoluted and optimized equilibrium constants and extinction coefficients of the hydrogen bonding species was determined. Using this information on FTIR line location/shape and equilibrium constants, the FTIR spectra of the amine-epoxy system during cure was quantitatively analyzed.

Effect of hydrogen bonding on determination of epoxy-amine reaction kinetics via FTIR

246th National Meeting (2013)

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