Realisation of siloxane ionomers by mild oxidation of alkylmercaptosiloxanes

Abstract

New siloxane polymers containing pendant mercaptopropyl and methyl groups have been synthesized by an acid-catalysed sol–gel reaction. The mercapto group was then oxidised to sulfonic acid using an excess of 3-chloroperoxybenzoic acid. This approach avoids the use of traditional strongly acidic sulfonating agents. Products with varying ratios of methyl and propanethiol/propanesulfonic acid constituents have been characterised by FT-infrared and NMR spectroscopies, elemental microanalyses, thermogravimetry and differential thermal analysis and ion exchange titrations.