Vdf containing (co) polymer with high molecular-weight using a new precipitation poly merization process

A precipitation polymerization method to produce PVDF having β phase wherein the method comprises the steps of providing a reactor with water, purging to remove oxygen said reactor with gas, heating said reactor, charging said reactor with vinylidene fluoride and optional non-fluorinated monomer to reach the desired pressure, charging initiator solution to said reactor, optionally continuously feeding the initiator solution during polymerization rate, wherein the temperature of the polymerization reaction is held constant at between 50° C. to 70° C., during the reaction and wherein the pressure is maintained between 280-40,000 kPa, feeding monomer to maintain pressure and continuing the polymerization reaction until the amount of VDF consumed reaches the preset level, venting surplus gas, recovering precipitated polymer by collecting the solids that precipitated during the polymerization reaction, wherein the amount of initiator used for the polymerization is at least 2000 ppm.