Radical Polymerizations of Vinyl Monomers in the Presence of α-Ethylsulfenyl Acrylonitrile

Radical polymerizations of styrene, methyl methacrylate, and acrylonitrile were carried out at 60°C in the presence of α-ethylsulfenyl acrylonitrile (α-ESAN). The rate of polymerization was found to be reduced by the addition of α-ESAN, and induction periods were observed when a large amount of α-ESAN was added to the systems. The chain transfer constant of α-ESAN was determined to be 2.0 and 17 for the polymerizations of styrene and methyl methacrylate, respectively. The Q, and e, values of α-ESAN were evaluated as 4.9 and -1.9, respectively. The presence of chromium(II) acetate and a-ESAN results in enhancement of α-ESAN activity as a retarder. From these results and ESR measurements, a mechanism of chain transfer is discussed.