Application of the Conant-Finkelstein reaction to the modification of PVC: Iodinated PVC

The Conant-Finkelstein reaction was applied to PVC with the aiming of replacing the chlorine atoms with iodine ones. The effect of reaction temperature with regard to the characteristics of the modified PVC was significant. Formation of a gel and degraded polymeric materials was observed when working at temperatures higher than 60 degrees C. The degraded polymer formed at 70 degrees C was insoluble and gave rise to a polyacetylene-like chain with a melting point of 60 degrees C. However, the reaction on PVC at lower temperatures resulted in soluble polymers which were easily amenable to spectral characterization. The molecular weights of the iodine-modified PVCs were temperature-dependent. At 40, 45, 50 and 60 degrees C, molecular weights lower than that of the initial PVC were measured; however, at 35, 30 and 25 degrees C, a gain of about 9% in molecular weight was seen. Substitution and elimination reactions occurred to different extents depending mostly on temperature. Optimal substitution was obtained at 50 degrees C for a reaction time of 20 h.