Synthèse et caractérisation de copolymères cellulose–poly(méthacrylate de méthyle): Greffage par le système acide de Caro–ion Fe3+

Methyl methacrylate was grafted onto cellulose using Caro's acid-Fe³⁺ system as initiator. The effect of grafting time, ferric ion concentration, and cellulose/monomer ratio, on the per cent grafting, was investigated. From studies of the reaction mechanism with model compounds it was postulated that the grafting did not occur at the 1,2-glycol units or at the hemiacetal unit in the end of the cellulose molecule. Concurrent degradation of the cellulose during the graft copolymerization was examined. A linear relationship between the per cent grafting and the number of cellulosic broken chains by hydrolysis was found, from which it would seem that the structure of the graft copolymer was of block-type. The structure of the graft copolymers was also studied by determination of the molecular weights of the grafted PMMA branches, after hydrolysis of the cellulosic backbone. In all cases, independently of reaction conditions, the molecular weights of the grafted branches were very high and their number low. The number of graft branches per cellulose chain was calculated from the per cent grafting, the molecular weights of the PMMA branches and of the cellulosic backbone. This number was compared with the number of cellulosic bonds broken during grafting.