| abstract |
The present invention relates to a process for the manufacture of PVDF homopolymer or copolymer by radical polymerization of vinylidene fluoride (VDF), and optionally of a comonomer, in aqueous dispersion and in the presence of a transfer agent, of a persulphate as radical initiator, optionally of a surface-active additive and optionally of a paraffin wax, in which:n a) an aqueous PVDF dispersion is obtained, b) the dispersion from stage a) is washed, optionally after having been coagulated, to lower the proportion of possible surfactant in the PVDF to below 300 ppm, this proportion being expressed with respect to the dried PVDF, c) sodium acetate and optionally a potassium alkylsulphonate are added to the dispersion washed in b), d) the dispersion from stage c) is dried by any means to recover the PVDF powder comprising sodium acetate and optionally a potassium alkylsulphonate. |