Process for the controlled radical polymerization or copolymerization of (meth) acrylic and vinyl monomers and (co) polymers obtained

A process for the controlled homogeneous live radical polymerization or copolymerization of (meth)acrylic and/or vinyl monomers, characterized in that at least one of the said monomers is polymerized or copolymerized in bulk, solution, emulsion or suspension in the presence of an initiator system comprising:

• at least one radical-generator compound other than an arenesulphonyl chloride;
• and
• at least one catalyst consisting essentially of a metal complex represented by formula (I) below:
• MA.sub.a (L).sub.n (I)
• in which:
• M represents Ni, Pd or Pt;
• A represents a halogen or a pseudohalide;
• the groups L are ligands of the metal M, which are chosen independently from those containing at least one from among N, P, As, Sb, and Bi, and optionally at least two of these ligands are connected together by one or more divalent radicals;
• a is an integer from 1 to 5;
• n is an integer from 1 to 4;
• with 4.ltoreq.a+n.ltoreq.6, a+n representing the coordination number of the complex, so as to obtain head to tail polymers having a molecular mass Mn of 400-10,000,000 g/mol and a polydispersity Mw/Mn less than 2 with a molecular control Mw/Mn up to about 1.1.