Graft Copolymerization of Acrylonitrile and Ethyl Methacrylate Comonomers on Cellulose Using Ceric Ions

Abstract

The graft copolymerization of acrylonitrile and ethyl methacrylate from their binary mixtures onto cellulose has been carried out in the presence of Ce(IV) ions in acidic media at 30 +/- 0.1 degrees C. The graft copolymerization has shown an increasing trend on increasing the feed molarity of the comonomers and on increasing the reaction time. The analysis of grafted cellulose prepared with different feed compositions (f(AN)) has clearly indicated the existence of the synergistic effect of ethyl methacrylate on acrylonitrile which normally shows poor affinity for grafting on cellulose while used individually. The elemental analysis and IR data were used to determine the composition of grafted copolymers and reactivity ratios (r(1), r(2)) of the monomers using the Mayo and Lewis method. The reactivity ratios for acrylontrile and ethyl methacrylate have been found to be 0.68 and 1.15, respectively, which supported the alternate arrangement of the monomer blocks of individual monomers in the grafted chains. The rate of grafting has shown a square dependence on the concentration of the comonomers within the studied range of feed molarity from 0.5 to 2.5 mol dm(-3). The grafting data were used to calculate the number of grafted chains (N(g)), frequency of grafting (G(F)) per molecule of the cellulose and efficiency of grafting (G(E)). The variation in these parameters as a function of feed molarity, feed composition, and ceric ion concentration has been determined. The rate of ceric ion disappearance as a function of feed molarity and reaction time has provided strong support to consider the participation of ceric ions in the formation of free radicals at the backbone of the cellulose. On the basis of the experimental observations, reaction steps for grafting of monomers on cellulose have been proposed.

Degradation of Acrylic Acid-Grafted Cellulose in Aqueous Medium With Radical Initiators

“…In adition to suitable reducing agents, especially organic acids, such as, H 2 C 2 O 4 , oxalic acid, permanganate provides efficient redox systems. Some such pairs are : KMnO 4 / tartaric acid [27] , KMnO 4 / malic acid [28] , KMnO 4 / H 2 C 2 O 4 [29], KMnO 4 /glyceric acid [30], Mn 3+ / ethoxyaceticacid redox systems [31] were studied in the aqueous polymerization of AAm Ceric ions are capable of forming radicals at the backbone of the cellulose in the presence of acid [32]. The grafting of monomers mixture on cellulose is carried out in aqueous medium.…”

Graft polymerization of vinyl monomers onto cotton fibres pretreated with amines

“…Reactive sites on the cellulose backbone are generated by either radiation or chemical initiation methods . Reports of graft polymerization of vinyl monomers, such as acrylic (Gurdag et al 2001;Pulat and Isakoca 2006), acrylate (Mondal and Hoque 2007; Saikia and Ali 1999), acrylamide (Ghosh et al 1995;Sahoo et al 1986) and acrylonitrile (Gupta and Sahoo 2001) monomers onto cellulose using both chemical and radiation methods are available in the literature.…”

Graft copolymerization of water‐soluble monomers containing quaternary ammonium group on poly(vinyl alcohol) using ceric ions

“…But the rate and extent of grafting by this method are usually low due to hindered diffusion of preformed polymers. Grafting of vinyl monomers onto natural polymers like guar gum, 8 starch, 9,10 and cellulose [11][12][13][14] by employing the ceric ion technique has been studied. Graft copolymerization is a powerful tool for obtaining polymers with new properties and applications.…”