Supported atom transfer radical polymerization of methyl methacrylate mediated by CuBr-tetraethyldiethylenetriamine grafted onto silica gel

Silica-gel particles grafted with tetraethyldiethylenetriamine were synthes ized as support for CuBr for the heterogeneous atom transfer radical polyme rization of methyl methacrylate (MMA). The immobilized CuBr mediated a livi ng polymerization of MMA, demonstrated by an increase in molecular weight w ith conversion and low polydispersity. An excessive amount of catalyst (typ ically, CuBr/initiator = 1.5) was required to achieve a living process beca use of the limited mobility of the supported catalyst. The silica-gel conce ntration had a strong effect on the polymerization. The recycled catalyst s till mediated a living process but showed a reduced catalytic activity due to the presence of Cu(II). After being regenerated by a reaction with Cu(0) , the catalyst regained its activity. (C) 2001 John Wiley & Sons, Inc.