Living Anionic Copolymerization of 1-(Alkylsulfonyl)aziridines to Form Poly(sulfonylaziridine) and Linear Poly(ethylenimine)

Abstract

The anionic ring-opening copolymerization of 1-(methylsulfonyl)aziridine (<b>MsAz</b>) and 1-(<i>sec</i>-butylsulfonyl)aziridine (^<b>s</b><b>BsAz</b>) produces a soluble random copolymer P(MsAz-<i>r</i>-^sBsAz), which can subsequently be converted to linear poly(ethylenimine) (lPEI). The copolymerization of <b>MsAz</b> and ^<b>s</b><b>BsAz</b> is living and allows for the synthesis of copolymers with low molecular weight distributions. Sequential anionic polymerization of <b>MsAz</b> and ^<b>s</b><b>BsAz</b> with 2-methyl-1-(methylsulfonyl)aziridine (<b>MsMAz</b>) creates P(MsAz-<i>r</i>-^sBsAz)-<i>b</i>-P(MeMsAz). Removal of the sulfonyl groups from P(MsAz-<i>r</i>-^sBsAz)-<i>b</i>-P(MsMAz) gives lPEI-<i>b</i>-poly(propylenimine). For the first time, lPEI can be synthesized by a controlled anionic polymerization.