POLYMERIZATION AND COPOLYMERIZATION OF SODIUM 10-UNDECEN-1-YL SULFATEIN MICELLES AND IN ADMICELLES ON THE SURFACE OF ALUMINA

Adsorption isotherms for sodium 10-undecen-1-yl sulfate (1) on alumina at ca. pH = 4.0, with and without styrene present, show behavior typi cal of anionic surfactants. Adsorption of 1 is greater in the presence of styrene. Thermal homopolymerization of 1 and copolymerization of 1 with styrene was carried out using ammonium persulfate as an initiato r in conventional micellar media and on alumina as surface admicelles. Homopolymerization of 1 proceeded for micellar systems only above the critical micelle concentration (cmc) to give polysurfactant 2 in vari able yield. Homopolymerization of 1 can occur at concentrations below the cmc of 1 using admicellar polymerization to give polysurfactant 2 in low yield. Copolymer from the micellar system (3) consists of mostl y styrene repeat units (> 99:1 styrene/surfactant, M(W) = 312 000; pol ydispersity = 4.8), while copolymers obtained from the admicellar syst em by extraction with chloroform (4, 3:1 styrene/surfactant, M(W) = 1 170 000; polydispersity = 2.1) and dimethylformamide (5, 20:1 styrene/ surfactant, M(W) = 86 000; polydispersity = 4.0) were relatively rich in surfactant repeat units. It is postulated that the higher degree of incorporation of surfactant into copolymer from the admicellar system arises from the fixed, ordered structure of admicelles relative to mi cellar structures, where normal emulsion polymerization appears to occ ur.