FREE RADICAL POLYMERISATION PROCESS

摘要

Process for the free-radical polymerisation of olefinically unsaturated monomer(s) using a free-radical initiator, wherein said polymerisation is performed in the presence of a compound for effecting molecular weight control, said molecular weight control compound being selected from Cobalt II chelates of formulae (I), (II) and (III), wherein: x and y are independently 2 to 5; each R<1>, R<2>, R<3> and R<4> is independently selected from H, C1-C12 alkyl, optionally substituted aryl, OR<5> where R<5> is C1 to C12 alkyl or optionally substituted aryl, CO2R<5>, SO3H, C(=O)R<5>, CO2H, NO2, OH, NR<5>2, NH2, NHR<5>, SR<5>, SH, CN, SO3R<5>, halogen, 2-furyl and 3-furyl; each X is independently selected from (CR<6>2)n, (CR<6>2O)n, optionally substituted o-phenylene, and optionally substituted 1,8-naphthylene, where each R<6> is independently selected from H and C1 to C12 alkyl, and n is 1 to 10; and wherein said cobalt chelates of formulae (I) and (II) possess a positive charge of 2 and are associated with an anion or anions for balancing the positive charge, while that of formula (III) is neutral; and also Co III analogues of said cobalt (II) chelates of formulae (I), (II) and (III) in which the Co atom is additionally covalently bonded, in a direction at right angles to the macrocyclic chelate ring system, to H, a halide ion or other anion, or a homolytically dissociatable organic group.