AGET ATRP of methyl methacrylatevia a bimetallic catalyst

Abstract

In this work, atom transfer radical polymerization with activators generated by electron transfer (AGET ATRP) of methyl methacrylate (MMA) using a novel bimetallic catalyst system based on FeCl₃·6H₂O/CuCl using tris(3,6-dioxaheptyl)amine (TDA-1) or triphenylphosphine (PPh₃) as ligand was carried out in bulk at 90 °C for the first time. The kinetics of the polymerizations with a molar ratio of [MMA]₀/[ethyl 2-bromoisobutyrate (EBiB)]₀/[FeCl₃·6H₂O]₀/[TDA-1 or PPh₃]₀/[CuCl]₀ = 300 : 1 : 0.5 : 1.5 : 0.1 were studied. At the same time, different reference experiments for the mono-metallic catalyst system (i.e., MMA/EBiB/FeCl₃·6H₂O/TDA-1 or PPh₃/ascorbic acid, MMA/EBiB/FeCl₃·6H₂O/TDA-1 or PPh₃, MMA/EBiB/FeCl₂·4H₂O/TDA-1 or PPh₃, MMA/EBiB/CuCl/TDA-1 or PPh₃) were also investigated. By comparison to these mono-metallic catalyst systems, both the polymerization rate and controllability over molecular weight and molecular weight distribution were enhanced for the bimetallic catalyst system. The nature of “living”/controlled free radical polymerization under bimetallic catalyst system was confirmed by chain extension experiments.