Novel pyrrole end-functional macromonomers prepared by ring-opening and atom-transfer radical polymerizations

New alpha-pyrrole macromonomers have been prepared using functional initiat ors by ring-opening polymerization (ROP) of epsilon-caprolactone and atom-t ransfer radical polymerization (ATRP) of different vinyl monomers. In the f irst case, the ROP of epsilon-caprolactone was initiated by a-pyrrolylethan l-ol at 110 degrees C using stannous octanoate as a catalyst. The functiona lization of the polymers was quantitative, and the molecular weight was wel l controlled by adjusting the monomer to initiator molar ratio. Alternative ly, ATRP of different monomers was carried out using 2-pyrrolylethyl 2-brom o-2-methylpropionate as the initiator in the presence of a CuBr/2-bipyridin e or NiBr2(PPh3)(2) as the catalyst at temperatures ranging from 70 to 110 degrees C. Using this controlled radical polymerization method, a-pyrrole h omopolymers and copolymers of styrene, methyl and tert-butyl methacrylate, n-butyl acrylate, poly(ethylene oxide methacrylate), (dimethylamino)ethyl m ethacrylate, and methyloxyethylethyl methacrylate have been prepared with c ontrolled molecular weights and narrow polydispersities.