Soc., 1994, vol. 116, pages 7943 ff, the use of a radical capping agent such as a nitroxide compound as described in Macromolecules, 1994, vol. 27, pages 7228 ff., and the technique of ???atom transfer radical polymerization (ATRP)??? which uses an organic halide or the like as the initiator and a transition metal complex as the catalyst.