Synthesis of poly(vinyl alcohol) having a thiol group at one end and new block copolymers containing poly(vinyl alchohol) as one constitent

Poly(vinyl alcohol) (PVA) and poly(vinyl acetate) having a thiol group at one end were synthesized by free-radical polymerization of vinyl acetate in presence of thioacetic acid as a chain transfer agent followed by treating with sodium hydroxide/methanol and ammonia, respectively. It was found that block copolymers containing the PVA sequence as one constituent were obtained by the redox-initiated polymerization of some vinyl monomers, for example, acrylic acid (AA) and acrylamide (AAm), using PVA having a thiol end group as reductant and an oxidant such as potassium bromate and potassium persulfate.