Process for radical controlled polymerization or copolymerization of (meth)acryl and vinyl monomers and thus prepared (co)polymers

This process is characterized by the fact that at least one of the said monomers is polymerized or copolymerized in bulk, solution, emulsion or suspension, at a temperature that can be as low as 0 DEG C., in the presence of an initiation system including: at least one compound generating radicals, other than bromofluorene, and at least one catalyst consisting of a complex of palladium in the 0 oxidation state, denoted by the following formula (I): Pd(0)L1L2L3L4 in which each of L1, L2, L3 and L4, which are identical or different, denotes a ligand which may be a chiral ligand, which is chosen from PRR'R'', P(OR)(OR')(OR''), NRR'R'', ORR', SRR', SeRR', AsRR'R'', SbRR'R'', where each of R, R' and R'' independently denotes a C1-C14 alkyl group, optionally substituted, or an optionally substituted aromatic group, it being possible for at least two of these ligands to be joined to one another by one or more divalent radicals.