The Polymerization of Styrene in the Presence of Sodium Salts of Higher Aliphatic Carboxylic Acids

The polymerization of styrene (St) in the presence of sodium oleate was investigated in an aqueous system without any ordinary radical initiators. The reaction proceeded at 800C to give a stable emulsion of poly(St) which has an unusually high molecular weights. St also pelymerized in the presence of sodium salts of saturated higher aliphatic carboxylic acids in the concentration range above their CMC. The polymerization rate ef St was independent on the carbon number of sodium salts of saturated carboxylic acids. St polymerized remarkably in the presence of surfactants such as sodium linolate or sodium linolenate having internal double bond with cis configuration or sodium undecylenate having external double bond, but scarcely polymerized in the presence of sodium elaidate containing internal double bond with trans configuration. In the presence of sodium linolate or linolenate, the polymerization of St would be initiated by the peroxide contained in surfactants, but the initiation mechanism of polymerization of St in the presence of sodium oleate was not clarified yet.