PVOH dispersant for VCM polymerization

A dispersing agent useful in a suspension polymerization process, the dispersing agent comprising:

• a polyvinyl alcohol formed by a process comprising:
• polymerizing a vinyl ester monomer to form a polyvinyl ester;
• partially hydrolyzing the polyvinyl ester to produce a partially hydrolyzed polyvinyl ester;
• heat treating the partially hydrolyzed polyvinyl ester to form the polyvinyl alcohol;
• wherein the partially hydrolyzing step comprises contacting the polyvinyl ester with an alkali hydroxide and with hydrogen peroxide;
• the polyvinyl alcohol having:
• a degree of hydrolysis in the range from 60 to 80 mol %;
• an absorbance of not less than 0.3 measured at a wavelength of 320 nm with respect to a 0.1 wt % aqueous solution of the polyvinyl alcohol;
• a block character of remaining ester groups in the range from 0.4 to 0.5;
• a cloud point in the range from 35° C. to 50° C. measured with respect to a 1 wt % aqueous solution of the polyvinyl alcohol;
• and
• carbonyl groups distributed along the length of the polymer chain;
• wherein the polymerizing step is preformed in the absence of both an added chain transfer agent and an added comonomer.