Supported Atom Transfer Radical Polymerization of Methyl Methacrylate Mediate by CuBr-Tetraethyldiethylenetriamine Grafted onto Silica Gel

摘要

Silica-gel particles grafted with tetraethyldiethylenetriamine were synthesized as support for CuBr for the heterogeneous atom transfer radical polymerization of methyl methacrylate (MMA). The immobilized CuBr mediated a living polymerization of MMA, demonstrated by an increase in molecular weight with conversion and low polydispersity. An excessive amount of catalyst (typically,CuBr/initiator=1.5) was required to achieve a living process because of the limited mobility of hte supported catalyst. The silica-gel concentration had a strong effect on the polymerization. The recycled catalyst still 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.