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

Abstract

New α-pyrrole macromonomers have been prepared using functional initiators by ring-opening polymerization (ROP) of ε-caprolactone and atom-transfer radical polymerization (ATRP) of different vinyl monomers. In the first case, the ROP of ε-caprolactone was initiated by 2-pyrrolylethan-1-ol at 110°C using stannous octanoate as a catalyst. The functionalization of the polymers was quantitative and the molecular weight was well controlled by adjusting the monomer to initiator molar ratio. Alternatively, ATRP of different monomers was carried out using 2-pyrrolylethyl 2-bromo-2-methylpropionate as the initiator in the presence of a CuBr/2-bipyridine or NiBr2(PPh3)2 as the catalyst at temperatures ranging from 70 to 110°C. Using this controlled radical polymerization method, α-pyrrole homopolymers and copolymers of styrene, methyl and tert-butyl methacrylate, n-butyl acrylate, poly-(ethylene oxide methacrylate), (dimethylamino)ethyl methacrylate, and methyloxyethylethyl methacrylate have been prepared with controlled molecular weights and narrow polydispersities.