ATRP by continuous feeding of activators: Limiting the end-group loss in the polymerizations of methyl methacrylate and styrene

Atom transfer radical polymerizations (ATRP) of methyl methacrylate (MMA) and styrene (St) were conducted by continuous feeding of Cu(I)/TPMA activators (TPMA: tris(2-pyridylmethyl)amine). Though the ATRP equilibrium constants are significantly different, the polymerizations of MMA and St were both well-controlled under similar reaction conditions giving polymers with relatively high monomer conversion, i.e., > 70%, and narrow molecular weight distributions, i.e., M-w/M-n < 1.2, in most cases. By reducing the total amount of Cu(I) used in these polymerizations, the mole percent of end-group loss (T-mol%) could be limited since T(mol% )in ATRP without activator regeneration should not exceed the molar ratio between Cu(I) and the initiator according to the principle of halogen conservation.