Determination of the epoxide equivalent weight (EEW) of epoxy resins with different chemical structure and functionality using GPC and 1H-NMR

A method for the determination and quantification of epoxide equivalent weights (EEW) and average functionality (F¯n) of different liquid and solid epoxy resins using gel permeation chromatography (GPC) and 1H-NMR spectrometry is described. Good correlations between GPC and 1H-NMR data were obtained regarding the estimation of the oligomers content within the epoxy resin compositions. Dependencies of average functionality against the polymerization degree and average-number molecular mass were pointed out and, subsequently, the EEW was calculated and compared with chemical analysis and suppliers data for all the epoxy resins studied.