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ABSTRACT:A sample of chemical cotton (pure cellulose) has been grafted with acrylonitrile (AN), methyl methacrylate (MMA) and acrylamide (AAd) using MnH ions complexed with pyrophosphate in acid aqueous solution (pH=l.7) at 30°C. The conversion of monomer to polymer and the add-on to the substrate weight have maxima at an MnH concentration of about 0.50 mM and at a monomer/substrate ratio of about 2: I. Under optimal conditions the grafting efficiency is about 95% for AN and 65-75% for MMA. For AAd the conversion is low (8-IO%) and the grafting efficiency < 50%. These results have been interpreted as due to the low accessibility of the cotton cellulose (high crystallinity)'and the known properties of the three monomers. The homopolymer formed of MMA is interpreted as largely due to chain transfer to monomer and that of AAd as mainly due to initiation by MnH oxidation of monomer. Alkaline hydrolysis of ANgrafted cotton fibers gives a water retention value of 65-70 g g-1 .KEY WORDS Cotton Cellulose / Graft Copolymerization / Vinyl Monomers / Manganic Ion Initiator / Alkaline Hydrolysis / Water Retention / A new redox system for initiation of graft copolymerization of vinyl monomers to polysaccharides has been developed in our laboratories and first applied to starch. 1 The initiator is Mn 3 + ions in complex form in aqueous solution of pH 1.5 to 2 at about 30°C. This initiator is also active with cellulose as substrate. 2 Both bleached cellulosic fibers from wood (lignin-free) and waterswelling cellulose ethers of low degree of substitution are efficiently grafted with this initiator. 3 using all known initiation methods appeared at the same time. 5 The purpose of this paper is to describe grafting experiments with a very pure cotton cellulose as substrate and complexed Mn 3 + ions in aqueous acid solution as initiator. Based on the results, the mechanism of initiation is discussed in detail, considering our recent studies of metal ion oxidation of model compounds. 6