Quantitative evaluation of an epoxy resin dispersion by infrared spectroscopy

A new method for the quantitative analysis of an epoxy resin dispersion by infrared (IR) spectroscopy is described. The absorbance ratio of various peaks in different areas of the IR spectra of a resin mixture, standardized to the IR absorbance of a peak for aromatic ring hydrogens (1593 cm(-1)), is applied to evaluate the conditions for epoxy resin dispersion. The standard deviation (s.d.) of the absorbance ratios in various regions of the spectra decrease as the resin mixing time increases, because of changes in the dispersion conditions. This s.d. value is used as the threshold value for determining the proper dispersion conditions. The threshold value enables quantitative evaluation of the epoxy resin; therefore, the proposed threshold value for proper resin dispersion may be a very important factor for process control in epoxy resin manufacturing.