CHARACTERIZATION OF ADDITIVES IN POLYOLEFINS USING NMR AND UV VISIBLESPECTROSCOPIC TECHNIQUES/

A novel method using NMR and uv/visible techniques has been developed for the identification and quantification of additives viz., antioxida nts and uv-stabilisers in polypropylene and ethylene propylene copolym ers. The procedure involves an efficient solvent extraction of additiv es from the polymer matrix followed by characterization by H-1 and C-1 3 NMR and estimation by uv/visible spectrophotometry. By employing shi ft reagent Eu(thd)(3), the overlapping signals of characteristic hydro xyl and t-butyl groups were well-resolved in the NMR spectra of additi ve mixtures. The uv/visible spectrophotometric method was used for ass aying these stabilizers in laboratory prepared polymer standards and g ood recoveries (>96%) were obtained. Subsequently this method has been extended to the additive extracts of commercial samples.