Graft copolymerization of acrylonitrile onto allylated caesarweed fibres by ceric ion in the presence of 2‐mercaptoethanol

Abstract

Polyacrylonitrile was grafted onto caesarweed fibers and on the allyldervative in aqueous media by ceric ion-2-mercaptoethanol redox pair. The allylfibre was obtained by treatment of caesarweed fibers with sodium hydroxide followed by allylchloride in diisoproylether to yield an average degree of substitution of 3.24 allyl moieties per anhydroglucose unit (AGU). The graft yield dependence on 2-mercaptoethanol concentration, in the range, 10.7-64.0 3 10 24M was characterized by a minimum followed by an enhanced yield. This suggested the existence of two initiating species, a thioglycol radical and mercaptoethoxyl radical. A fivefold increase in the concentration of 2-mercaptoethanol was accompanied by reduction in the frequency of graft, . Infrared spectroscopy of allylfibre-g-polyacrylonitrile copolymer showed evidence of radical coupling reaction involving thioglycol radical species and allylic macroradicals of the allylfibre. The unmodified fiber was more reactive than the allylfibre by as much as a factor of 2, and was ascribed to resonance stabilization of allylic macro radicals derived from the latter. For the allyl fiber, a 150% increase in monomer concentration resulted in nominal increase in graft yield, not higher than 7%.

Graft Copolymerization of Acrylamide and Methylmethacrylate onto Cellulose Fibres: Influence of Initiator in Gel Formation

“…Graft copolymerization of vinyl monomers has been attempted during recent years using chemical initiators (Ogiwara and Kubota, 1973;Eromosele, 1994a, b;Eromosele and Ahmed, 1996;Nwufo and Ishaku, 2000a, b;Eromosele and Solomon, 2000;Aminu and Nwufo, 2004).…”