Synthesis of a well-defined polybromostyrene by living radical polymerization with a nitroxyl radical

Radical polymerization of p-bromostyrene was investigated with benzoyl peroxide (BPO) as an initiator in the presence of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO). The polymerization was performed in bulk for 3.5 h at 95 degrees C and then continued for another 48 h at 125 degrees C to afford the corresponding polybromostyrene with a narrow molecular weight distribution in high yield. H-1 NMR study revealed that the polymer obtained had BPO and MTEMPO moieties at its head and tail, respectively. It was confirmed that the polymerization proceeded in accordance with living mechanism, because the molecular weight linearly increased with an increase of the conversion, and it was directly proportional to the reciprocal of the initial concentration of BPO. Furthermore, the poly styrene obtained in the present study could quantitatively act as the initiator for the polymerization of p-bromostyrene in the living radical manner to afford the corresponding block copolymer, and vice versa. (C) 1996 John Wiley & Sons, Inc.