Relaxation studies of modified-poly(vinyl alcohol) by dynamic infrared spectroscopy

A dynamic infrared spectrometer was developed by combining a FT-IR spectrometer with a visco-elastometer in order to analyze relaxations of polymers in terms of functional groups. The polarized-infrared spectrum synchronized with vibrations applied to samples by a visco-elastometer could be measured in the temperature range of 26similar to150degreesC and in the frequency range of 1similar to300 Hz. A series of modified-poly(vinyl alcohol) (PVA) samples was analyzed by this instrument. The relaxation of hydroxyl group of acethyl-modified PVA was detected. Thus, the synchronous spectrum (in-phase spectrum) changed with the frequency as well as with the temperature. The relaxations of the principal functional groups in a series of modified-PVA such as butyral-modified PVA and fluoroacetyl-modified PVA were detected. Further, the tendency of the change of the glass transition temperature with the degree of modification was elucidated in terms of the relaxation of the functional groups.