The emulsion polymerisation of vinyl acetate by redox initiation

Redox initiation enables polymerisation to be carried out at relatively low temperatures, and has been extensively studied in relation to styrene‐butadiene and acrylic esters. In the case of vinyl acetate, the hydrogen peroxide‐iron initiator system has been examined in detail, but is normally satisfactory only at higher temperatures of polymerisation (70 to 80 °C). The low temperature redox polymerisation of vinyl acetate appears to have received little attention. In the present work, the emulsion polymerisation of vinyl acetate using ammonium persulphate with a reducing agent and a metal ion has been studied at 50 ° C. It is shown that to achieve maximum conversion of monomer to polymer the selection of both the reducing agent and the metal ion is important, and that the pH profile during the process is critical. These results are related to the availability of the metal ion at the locus of polymerisation.