The cationic copolymerization of diglycidyl ether of bisphenol-A with tetrahydrofuran initiated by phosphotungstic acid was in-situ investigated by Fourier transform near-infrared spectroscopy. It was found that the consumption rate of epoxy groups did not change with reaction time at low epoxy concen-
trations, while it decreased with the reaction time at a high epoxy concentration. In addition, the peak splitting pattern of the overlapping C—H vibration region was developed. The peak splitting analysis of the spectra showed that the copolymerization did occur, which was further proved by the results of generalized two-dimensional correlation analysis. Furthermore, the relationship between the consumption rate and the concentration of the epoxy groups was discussed.

Key words: polyoxometalate, cationic polymerization, epoxy