Reverse atom transfer radical polymerisation (RATRP) of methacrylates using copper(I)/pyridinimine catalysts in conjunction with AIBN

N-n-Propyl-2-pyridylmethanimine, 1, N-n-octyl-2-pyridylmethanimine, 2, N-n-lauryl-2-pyridylmethanimine, 3, and N-n-octadecyl-2-pyridlmethanimine, 4 have been used in conjunction with copper(II) bromide and azo initiators for the reverse atom transfer radical polymerisation of a range of methacrylates. AIBN to Cu(II)Br(2) ratios of 0.5:1, 0.75:1 and 1:1 give PMMA with M(n) 11500 g mol(-1) (PDi = 1.24) (at 22% conversion), 12 500 g mol(-1) (PDi = 1.06) (at 83% conversion) and 10 900 g mol(-1) (PDi = 1.11) (at 84% conversion), respectively. A Cu(II)Br(2) complex is demonstrated to be needed at the start of the reaction for good control over molecular weight and polydispersity as reactions using Cu(I)Br as catalyst yielded PMMA of M(n) 31000 g mol(-1) (PDi = 2.90), reactions with no copper yield PMMA of M(n) 33 000 g mol(-1) (PDi = 2.95). The RATRP of styrene was carried out using Cu(II)Br(2) as catalyst. AIBN to Cu(II)Br(2) ratio of 0.5:1, 0.75:1 and 1:1 gave PS with M(n) = 12400 g mol(-1) (PDi = 1.27) at low conversion, M(n) = 15500 g mol(-1) (PDi = 1.11) and 12400 g mol(-1) (PDi = 1.38), respectively at similar to 85% conversion. A series of block copolymers of MMA with BMA, BzMA and DMEAMA (15600 g mol(-1) (PDi = 1.18), 13300 g mol(-1) (PDi = 1.14) 15300 g mol(-1) (PDi) = 1.16), using a PMMA macroinitiator were prepared. Emulsion polymerisation of MMA using [initiator]: [Cu((II))Br(2)] ratio = 0.5:1 with Brij surfactant gave a linear increase of Mn with respect to conversion, final M,, = 112800 g mol(-1) (PDi = 1.42). Further reactions were carried out with [initiator]:[Cu((II))Br,] ratio = 0.75:1 and 1:1. Both giving PMMA with M(n) similar to 32000 g mol(-1) (PDi similar to 2.4). These reactions exhibit no control, this is because the azo initiator is present in excess and all of the monomer is consumed by a free radical polymerisation as opposed to a controlled reaction. Particle size analysis (DLS) showed the particle size between 160 and 170 nm in all cases. (c) 2005 Published by Elsevier Ltd.