Crosslinking of Starch Xanthate. V. Redox Grafting with Hydrogen Peroxide and Vinyl Monomers in Water

Maher, George G.

doi:10.1295/polymj.11.85

Cited by 7 publications

(1 citation statement)

References 18 publications

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“…A further possibility of initiating the graft polymerization is to bind initiating groups directly to the starch molecule, which can be activated thermally or chemically. For example, a thiocarbamate derivative of starch can be grafted by the addition of H 2 O 2 , or iron peroxodisulfate . Peroxy, − azonium, , and azo groups are the common thermally cleavable groups; starch derivatives of these groups are typical starch macroinitiators.…”

Section: Introductionmentioning

confidence: 99%

Cationic Polymer Grafted Starch from Nonsymmetrically Substituted Macroinitiators

et al. 2005

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The aim of this work was the synthesis of starch macroinitiators for cationic polymer grafted starches that: W are free of cationic homopolymer, and (ii) display a high degree of conversion of the cationic monomer. We show that this can be achieved by a free-radical polymerization reaction using the cationic monomer N-methaeryloyloxyethyl-N,N-dimethyl-N-benzylammonium chloride (XLADAM-BQ) and a new starch-based macroazoinitiator. For this purpose, the acid chloride of 4-tert-butylazo-4-cyanovaleric acid was synthesized and bound covalently to starch (predominantly in the C6 position) to form a nonsymmetrically substituted macroinitiator that was used to polymerize MADAM-BQ in aqueous media. Essentially no MADAM-BQ homopolymer was formed. The initiator decomposes thermally to starch radicals of high reactivity and low-molar mass radicals that do not initiate polymerization. The reason for the different reactivities of the radicals is presumably due to the nonsymmetric constitution of the starch-bound azo groups. The graft polymerization of MADAM-BQ in aqueous solution performs according to an ideal overall kinetic. The structure of the synthesized starch-graft-poly(MADAM-BQ) products is similar to that of block copolymers because of the low radical efficiency of the starch initiators in aqueous solution. Especially, starch substrates with a higher content of azo groups did not lead to graft products with shorter graft distances because the state of solution of these macroinitiators becomes worse and aggregation occurs with an increasing degree of substitution

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Section: Introductionmentioning

confidence: 99%

Cationic Polymer Grafted Starch from Nonsymmetrically Substituted Macroinitiators

et al. 2005

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Graft polymerization of acrylamide onto maize starch using potassium persulfate as initiator

Khalil

Mostafa

Hebeish

1993

Angew. Makromol. Chem.

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Graft polymerization of acrylamide (Aam) onto maize starch using potassium persulfate as initiator was investigated under different conditions including concentration of initiator and monomer, polymerization time and temperature and liquor ratio. Based on the results obtained, appropriate conditions for grafting acrylamide onto starch were established. These conditions were also used for grafting other monomers onto maize starch. Results obtained indicate that acrylamide acquires the highest graft ability while acrylic acid acquires the least, while acrylonitrile and methacrylic acid in between. The water solubility of both nitrogen-and carboxy-containing copolymers increases by increasing the monomer content up to a certain value, then it decreases. ZUSAMMENFASSUNG:Die Pfropfcopolymerisation von Acrylamid (Aam) auf Maisstarke wurde mit Kaliumpersulfat als Initiator bei unterschiedlichen Reaktionsbedingungen, wie Initiatorbzw. Monomerkonzentration, Reaktionszeit und -temperatur sowie dem Feststoffgehalt untersucht. Basierend auf den erhaltenen Ergebnissen wurden die geeignetsten Bedingungen ausgewahlt und den Pfropfpolymerisationen von anderen Monomeren auf Maisstarke zugrundegelegt. Von den eingesetzten Monomeren zeigte Acrylamid die grorjte Pfropffahigkeit, Acrylsaure die geringste; Acrylnitril und Methacrylsaure lagen dazwischen. Die Wasserloslichkeit sowohl von stickstoffhaltigen als auch von Carboxygruppen enthaltenden Copolymeren steigt zunachst mit steigendem Monomergehalt an und sinkt ab einem bestimmten Wert wieder.

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Grafting starch xanthate with vinyl monomers and hydrogen peroxide in foam rubber production

Maher

1979

J of Applied Polymer Sci

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SynopsisStarch xanthate with degrees of substitution (D.S.) ranging from 0.12 to 0.56 reacted with vinyl monomers (acrolein, acrylamide, acrylic acid, acrylonitrile, methyl acrylate, or styrene) and hydrogen peroxide to form aqueous gels of starch-polyvinyl monomer graft copolymer. The same reactions conducted in a rubber latex medium resulted in a self-acidifying, self-heating, and self-foaming coagulation to give a foam rubber. Such products were formed from several synthetic latices (NBR, SBR, polyisoprene, and polychloroprene types) and natural rubber latex; noted for each were the effects of the D.S., of monomer and peroxide concentrations, and of starch:elastomer ratios. The dried foams were evaluated by standard strength tests. Foam rubber of acceptable extensibility and enhanced tensile strength (up to 110 psi) was obtained with 0.12-0.15 D.S. xanthate and with proper balance of vinyl monomer, peroxide, and starchelastomer ratio. Resilience was fair to good, but compression set was rather poor compared to most foam rubbers of general use.

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Crosslinking of Starch Xanthate. V. Redox Grafting with Hydrogen Peroxide and Vinyl Monomers in Water

Cited by 7 publications

References 18 publications

Cationic Polymer Grafted Starch from Nonsymmetrically Substituted Macroinitiators

Cationic Polymer Grafted Starch from Nonsymmetrically Substituted Macroinitiators

Graft polymerization of acrylamide onto maize starch using potassium persulfate as initiator

Grafting starch xanthate with vinyl monomers and hydrogen peroxide in foam rubber production

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