Mechanism of graft co-polymerization onto polysaccharides initiated by metal ion oxidation reactions of model compounds for starch and cellulose

Doba, Takahisa; Rodehed, Cenita; Rånby, Bengt

doi:10.1021/ma00142a009

Cited by 49 publications

(25 citation statements)

References 9 publications

(9 reference statements)

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“…According to this point of view, the most probable position of cleavage in glucosidic ring is C 2 -C 3 bond. Doba et al [27] suggested, considering the large number of repeating diol groups along the polysaccharide chain, that both C l -C 2 (end groups) and C 2 -C 3 glycol groups are predominant sites for initiation of graft copolymerization. Thus, the anhydroglucose units of chitosan interacting with the Ce 4+ ions are precisely oxidized in this position.…”

Section: Discussion Characteristics Of Obtained Materials By Uv-vis mentioning

confidence: 99%

Preparation and characteristics of nanosilver composite based on chitosan-graft-acrylic acid copolymer

2015

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The aim of this work was to prepare and characterize the novel antibacterial nanocomposites based on chitosan, grafted acrylic acid and silver nanoparticles (AgNPs). Chitosan has been functionalised by chemical reaction with acrylic acid, and then mixed with silver nanoparticles (AgNPs). AgNPs have been obtained formerly by chemical reduction of silver nitrate in the presence of mercaptosuccinic acid as a nanoparticles stabilizer. Structure and properties of obtained nanocomposite have been characterised by UV-vis, FTIR and 13C-NMR spectroscopy. The morphology of silver chitosang-acrylic acid nanocomposite has been studied by electron microscopy (SEM/EDX and HR-TEM). Thermal stability has been investigated by thermogravimetric analysis. The grafted chitosan contained 70.9 % wt acrylic acid, as determined by gravimetric method. It was found that modified chitosan forms water-insoluble gel with lower thermal resistance than pure chitosan. However, the difference between thermal properties of grafted chitosan and its nanocomposite with AgNPs is negligible. The grafting reaction mechanism has been discussed in detail on the basis of the obtained results and current literature data.

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Section: Discussion Characteristics Of Obtained Materials By Uv-vis mentioning

confidence: 99%

Preparation and characteristics of nanosilver composite based on chitosan-graft-acrylic acid copolymer

2015

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“…This scheme is based on a fact that both the C1-C2 (end groups) and C2-C3 are predominant sites for the initiation of graft copolymerization [17]. Most commonly, graft polymerization is brought about by free radical addition polymerization.…”

Section: Resultsmentioning

confidence: 99%

Graft copolymerization of acrylic acid onto hydrolyzed potato starch using various initiators

Djordjević

Nikolić

Kovačević

et al. 2013

Per. Pol. Chem. Eng.

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“…6 The Mn 3 + ions are oxidizing aldehyde groups (eq l) and vicinal diol groups (eq 2) by one-electron reactions:…”

Section: Discussionmentioning

confidence: 99%

“…5, 1987 cording to eq 2, e.g., 1,2-cyclohexane-diol and monosaccharides with several vicinal diol groups like o-ribose. 6 The acrylamide monomer in aqueous solution of low pH would be enolized by addition of water and react in this form: (3) Mn3+ (eq 2), the alkhydi:oxy radical can be further oxidized to an aldehyde group (eq 4). This would mean a consumption of grafting sites by an excess of Mn 3 + ions charged, i.e., a decrease in conversion of monomer to polymer, which agrees with the experimental results for grafting of AN to cotton cellulose (Table I and Figure 1).…”

Section: Hoch-ch= C-nhmentioning

confidence: 99%

“…Based on the results, the mechanism of initiation is discussed in detail, considering our recent studies of metal ion oxidation of model compounds. 6 A review of new graft copolymerizations onto cellulosic fibers using chemical initiation has recently been published. 4 An extensive monograph on grafting to cellulosic materials cotton !inters pulp for papermaking and cellulose derivatives, is used in never-dried form (supplied as 35.65% dry weight).…”

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Graft Copolymerization of Vinyl Monomers onto Pure Cotton Cellulose Using Mn3+ Ions as Initiator

Rånby

Zuchowska

1987

Polym J

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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

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Mechanism of graft co-polymerization onto polysaccharides initiated by metal ion oxidation reactions of model compounds for starch and cellulose

Cited by 49 publications

References 9 publications

Preparation and characteristics of nanosilver composite based on chitosan-graft-acrylic acid copolymer

Preparation and characteristics of nanosilver composite based on chitosan-graft-acrylic acid copolymer

Graft copolymerization of acrylic acid onto hydrolyzed potato starch using various initiators

Graft Copolymerization of Vinyl Monomers onto Pure Cotton Cellulose Using Mn3+ Ions as Initiator

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