Normal Vibrations of Polyacrylonitrile and Deuterated Polyacrylonitriles

Abstract

Polarized infrared spectra of polyacrylonitrile, poly-α-deuteroacrylonitrile, poly-β,β-dideuteroacrylonitrile and poly-α,β,β-trideuteroacylonitrile have been measured in the region from 4000 to 200 cm—1. β,β-dideuteroacrylonitrile was prepared by the hydrogen re-exchange reaction of α,β,β-trideuteroacrylonitrile with H2O in the presence of CaO. The calculations of the normal vibrations of polyacrylonitrile and these three polydeuteroacrylonitriles have been made, assuming a syndiotactic planar zigzag chain as the most simple model for calculation. The calculation was made by the use of the GF-matrix method with the Urey—Bradley force field. The results show fairly good agreement between the observed and calculated frequencies. The assignments of the bands are given and discussed.