Ceric ion‐induced redox polymerization of acrylonitrile on cellulose

Abstract

SynopsisThe ceric ion-cellulose redox system has been studied for grafting acrylonitrile on cotton fibers. Grafting yields are very high as compared to the persu1fat)ethiosulfate redox system reported earlier. Traces of copper sulfate in the reaction mixture do not increase grafting yields, unlike the persulfate-thiosulfate system. The high polymerization rate on cotton fibers is shown to be due to the reducing action of cellulose and not to the large surface area of cotton fibers. The Ce+4 consumption during grafting is higher than during oxidation of cellulose, indicating formation of homopolymer during the grafting reaction. Studies on the consumption of Ce+4 by model compounds siich as D-glucose and a-methyl-D-glucoside show that the hemiacetal group in D-glucose is responsible for a faster rate of Ce+' Consumption. Formation of a Ce+'-alcohol complex also contributes to the initial fast rate of Cef4 consumption. Studies on the oxidation of celldose by Ce+4 indicate that the initial oxidative attack occurs on carbon atom 2, with the formation of a >C=O group. On further oxidation, cleavage of the C2-G bond occurs as shown by the presence of glycol aldehyde determined chromatographically. Cellulose-polyacrylonitrile grafts have been isolated by an acetolysis treatment followed by extraction with dimethylformamide. Number-average molecular weight,s of the isolated fractions are approximately 50,000-55,000. A theoretical method to calculate the number-average molecular weights, based on the PAN and the COOH contents of the grafted cellulose, is described.

Graft copolymerization of acrylonitrile onto delignified native bamboo (Bambusa vulgaris) cellulosic and its utilization potential for heavy metal uptake from aqueous medium

“…The decreasing effect by prolonging this soaking time beyond 60 min could be attributed to the decay of free radical activity of ceric ions oxidized cellulose resulting from the free radical termination by charge transfer. A similar trend was observed by Hon [21] and Kulkarni and Mehta [22]. Effect of ceric ammonium nitrate concentration…”

Grafting of methyl methacrylate (MMA) onto Antheraea assama silk fiber

“…All polymerization reactions were carried out in air 18, 19. A three‐necked 300‐mL round‐bottomed flask fitted with stirrer in a temperature‐controlled water bath was used for the reactions.…”

A UV-Vis Spectrophotometric Method for the Estimation of Aldehyde Groups in Periodate-Oxidized Polysaccharides Using2,4-Dinitrophenyl Hydrazine

“…An alternative method for the generation of aldehyde units in polysaccharides was put forth by Kulkarni and Mehta. [33] In a manner similar to periodate oxidation, the vicinal diols present on the C2 and C3 carbons are converted to aldehyde moieties. However, this methodology has not been pursued much due to the difficulty in separating leftover Ce 4+ from the reaction medium.…”