<p>The invention pertains to a method for manufacturing a dispersions of a grafted copolymer, said method comprising: providing a dispersion of particles at least one vinylidene fluoride (VDF) polymer [polymer (F)] in a liquid medium comprising at least one latent solvent for polymer (F), wherein said polymer (F) is substantially insoluble at a temperature of 25°C in said liquid medium; reacting in said liquid medium said polymer (F) with an ATRP catalyst comprising at least one transition metal salt and at least one ligand and with an ethylenically unsaturated comonomer [comonomer (A)] at a temperature higher than 25°C wherein said polymer (F) is at least partially swelled in said liquid medium; cooling said liquid medium so as to obtain a dispersion of particles of grafted copolymer of polymer (F) and comonomer (A).</p>
