Infrared spectra of high polymers. V. Polyvinyl alcohol

Abstract The infrared spectrum of polyvinyl alcohol has been investigated between 3600 and 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 The spectrum of a deuterated specimen (about 90% of the OH having been replaced by OD) has also been obtained. These data confirm and extend the results of previous workers. The spectrum is discussed in detail in relation to three structures for polyvinyl alcohol proposed on the basis of x‐ray diffraction studies. The data definitely rule out the structure proposed by Mooney, and are most consistent with the structure proposed by Bunn. A complete assignment of the bands in the spectrum is proposed. From this analysis it appears that the existence of interaction forces between molecules can be convincingly demonstrated. The proposed assignments suggest a new interpretation of the 1326–1446 cm. −1 doublet, viz. , that these bands arise from mixed CH and OH in‐plane bending vibrations. This is shown to be in agreement with the results of studies on simple alcohols. An alternative assignment for the 1144 cm. −1 band is also considered.