THE INFRARED SPECTRUM AND STRUCTURE OF POLYVINYL ALCOHOL

Abstract

The infrared spectrum of polyvinyl alcohol has been obtained from $3600 cm^{-1}$ to $70 cm^{-1}$. Polarization measurements on stretched specimens were made down to about $330 cm^{-1}$. The spectrum of a deuterated specimen (about 90% of the OH having been converted to OD) has also been obtained. From x-ray diffraction studies, $Mooney^{1}$ and $Bunn^{2}$ have proposed slightly different structures for polyvinyl alcohol. On the basis of the parallel dichroism of the band near $650 cm^{-1}$, the structure proposed by Mooney can be ruled out. The observed spectrum does, however, appear to be consistent with Bunn’s structure. As a result of recent detailed studies on the infrared spectra of $alcohols^{3}$, it is possible to make definite assignments of all of the OH bands in polyvinyl alcohol with the exception of one near $1445 cm^{-1}$. This band presumably corresponds to the $1410 cm^{-1}$ band in the alcohols, whose interpretation has been uncertain. A possible assignment of this band will be discussed, as well as an interpretation of the remainder of the spectrum.