Hyperbranched Polymers by Visible Light Induced Self-Condensing Vinyl Polymerization and Their Modifications

Visible light induced self-condensing vinyl polymerization is explored using 2-bromoethyl methacrylate (2-BEMA) and methyl methacrylate (MMA) as inimer and comonomer, respectively, in the presence of dimanganese decacarbonyl (Mn-2(CO)(10)) for the preparation of hyper-branched polymers. Upon photoexcitation in the visible range, Mn-2(CO)(10) undergoes irreversible decomposition leading to the formation of initiating radicals through bromine abstraction from 2-BEMA. Depending on the concentrations of 2-BEMA and Mn-2(CO)(10) and irradiation time, hyperbranched polymers with different branching density and cross-linked polymers were formed. The resulting polymers possess unreacted bromide groups in the structure which allow postfunctionalization through visible light photopolymerization and Cu(I)-catalyzed click reactions.