Radical reduction as a means for complete desulfuration of MADIX polymers
Abstract
One potential drawback of the MADIX process lies in the fact that the xanthate terminal group, if not deactivated, is likely to be degraded during the lifetime of the polymer or under some specific application conditions. Several appropriate treatments were developed by our group in order to prevent an uncontrolled degradation over time which may eventually generate low molecular weight malodorous, potentially toxic sulfur-based by-products. For instance, the radical reduction of xanthate terminal groups of PDMS and MADIX polymers was efficiently conducted with peroxide and percarbonate initiators in secondary alcohols, e.g. isopropanol. This technique advantageously leads to sulfur-free polymers, unlike most of the known alternative techniques for the transformation of xanthates.