Efficiency of ligands in atom transfer radical polymerization of lauryl methacrylate and block copolymerization with methyl methacrylate

Atom transfer radical polymerization of lauryl methacrylate (LMA) was carried out in the presence of various ligands using ethyl-2-bromoisobutyrate as initiator and CuBr as catalyst in toluene at 95 degreesC. The ligands used were 2,2'-bipyridyl,4,4'-dimethyl-2,2'-bipyridyl, N,N,M,A,N''-pentamethyidiethylenetriamine (PMDETA) and N-(n-propyl)-2-pyridylmethanimine (PPMI). Controlled polymerization was observed with PMDETA and PPMI ligands and poly(LMA)s with narrow molecular weight distribution (MWD) (M-w/M-n less than or equal to 1.2) were obtained. The first-order time-conversion plot showed the presence of termination in the presence of PMDETA. A linear first-order time-conversion plot with a small induction period (similar to 10 min) was observed in the presence of PPMI ligand. Di-block copolymers of LMA and methylmethacrylate with controlled molecular weight and narrow MWDs were synthesized via sequential monomer addition. (C) 2004 Elsevier Ltd. All rights reserved.