A study of the CCl stretching region of the Raman spectrum of PVC

The C-Cl stretching regions of the Raman spectra of a number of samples of PVC prepared by various methods which lead to differences in tacticity, conformational content and crystallinity have been studied. It is shown that the spectra of all samples can be fitted well with a set of nine Lorentzian peaks whose positions and widths are the same for each spectrum. Two of these peaks are attributable to the A_g and B_3g species vibrations of crystalline material and the remaining seven may be assigned with reasonable confidence to specific structures in the amorphous regions, three of which are associated with isotactic placements. The area under the A_g and B_3g peaks may be used to estimate the crystallinity of the samples and the area under the peaks assigned to isotactic material may be used to estimate the tacticity of the polymer.