RAMAN-SPECTROSCOPIC STUDIES OF THE POLYACRYLONITRILE ZINC-COMPLEXES IN AQUEOUS-SOLUTIONS OF ZINC-CHLORIDE AND BROMIDE

Raman spectroscopic studies of the dissolution of polyacrylonitrile (PAN) in aqueous zinc halides are reported. The dissociation constants of aqueous PAN-zinc chloride and PAN-zinc bromide containing 60-75% wt/wt and 65-80% wt/wt zinc in aqueous polyacrylonitrile solutions, respectively, have been measured by Raman spectroscopy. Intensity measurements allowed for a quantitative measurement of the amount of free and complexed CN groups to be made, utilising the 2259 and 2290 cm-1 nu(CN) stretching Raman bands. The degree of complexation was found to be small in many of the solutions. The effect of the addition of salt on the structure of the nu(OH) band at 3000-3800 cm-1 was studied for the aqueous zinc salts and an aqueous sodium thiocyanate solution. The low wavenumber regions of the Raman spectra, DELTAnu = 100-350 cm-1, for both zinc chloride and zinc bromide solutions of PAN have also been studied.