Polyvinyl alcohol and method for producing same

A method for producing a polyvinyl alcohol, the method comprising:

• adding vinyl ester monomers, a radical initiator and an organic cobalt (II) complex to a reactor;
• polymerizing the vinyl ester monomers by controlled radical polymerization in the reactor to obtain a polymer solution comprising a polyvinyl ester;
• extracting a cobalt complex from the polymer solution by contacting an aqueous solution comprising a water-soluble ligand with the polymer solution;
• and
• saponifying the polyvinyl ester after the extracting to obtain the polyvinyl alcohol.

A method for producing a polyvinyl alcohol, the method comprising:

• polymerizing vinyl ester monomers by controlled radical polymerization in the presence of a radical initiator and an organic cobalt complex to obtain a polymer solution comprising a polyvinyl ester;
• extracting a cobalt complex from the polymer solution by contacting an aqueous solution comprising a water-soluble ligand with the polymer solution;
• and
• saponifying the polyvinyl ester after the extracting to obtain the polyvinyl alcohol,
• wherein the radical initiator is selected from the group consisting of azo initiators, peroxide initiators and redox initiators.