Polymer homologue of DMSO: synthesis of poly(ethylene sulfoxide) by selective oxidation of poly(ethylene sulfide)

摘要

Poly(ethylene sulfoxide) having almost 100% sulfinyl groups in the main chain was synthesized by selective oxidation of poly(ethylene sulfide). Poly(ethylene sulfide), prepared by anionic ring-opening polymerization of ethylene sulfide, was reacted in a HNO3/CH3SO3H system at 0°C for 24 h to give poly(ethylene sulfoxide) in quantitative yield. The structure of the polysulfoxide obtained was confirmed by 1H NMR, 13C NMR, and IR spectra. A shorter reaction time caused insufficient oxidation, and the polymer containing sulfoxide and sulfone units was obtained when the reaction was conducted at room temperature. The resulting poly(ethylene sulfoxide) was soluble in 60% HNO3, methanesulfonic acid, and trifluoromethanesulfonic acid, though poly(ethylene sulfide) was insoluble in any solvent at room temperature. Poly(ethylene sulfoxide) was found to be miscible with poly(vinyl alcohol). These results reflect that poly(ethylene sulfoxide) has a repeating structure of dimethyl sulfoxide, which is known as an aprotic polar solvent.