Gangadhar Sahu

Photoinduced graft copolymerization: X—Graft copolymerization of methyl methacrylate onto wool using isoquinoline-sulphur dioxide charge-transfer complex as the initiator

Abstract The photoinduced graft copolymerization of methyl methacrylate onto wool fibre was investigated using an isoquinoline-sulphur dioxide charge-transfer complex as the initiator. The percentage of graft yield increases with increasing concentration of the monomer and the initiator. The reaction was carried out at three different concentrations and the overall activation energy was computed. The kinetic data and other evidence indicate that the overall polymerization takes place by a radical mechanism. A suitable kinetic scheme has been suggested.

Grafting Vinyl Monomers onto Chemically Modified Wool Fibers: Graft Copolymerization of Methyl Methacrylate onto Reduced Wool Fibers Using Acetylacetonate Complex of Manganese(III)

Abstract The graft copolymerization of methyl methacrylate (MMA) onto reduced Indian Chokla wool fibers was studied in aqueous solution using the acetylacetonato complex of Mn(III) as the initiator. Perchloric acid was found to catalyze the reaction. The rate of grafting was investigated by varying the concentration of the monomer and the complex, acidity of the medium, the temperature, and the reaction medium. It is observed that the graft yield increases with increasing concentration of the chelate and acid and with increasing temperature. There is an increase in graft yield within a certain concentration range of the monomer, after which it falls. The grafting is considerably influenced by changing the solvent composition of the reaction medium. A comparative study reveals that oxidized and reduced wools are better substrates than untreated and other chemically modified wools. The effect of various monomers on graft yield is investigated. MMA is found to be a most active monomer compared to other vinyl...

Grafting Vinyl Monomers onto Wool Fibers. X. Graft Copolymerization of Methyl Methacrylate onto Wool Using Acetylacetonato Complex of Manganese(lII)

Abstract The graft copolymerization of methyl methacrylate onto wool fibers was investigated in aqueous solution using the acetylacetonato complex of manganese(III). The rate of grafting was determined by varying the monomer, the complex, the temperature, the acidity of the medium, the nature of the wool, and the reaction medium. The graft yield increases with increasing monomer and complex concentrations. The graft yield also increases with increasing temperature. The grafting is considerably influenced by chemical modification of wool prior to grafting. A suitable mechanism has been proposed and a rate equation has been derived.

Vinyl Polymerization of Acrylonitrile Initiated by Thallium(lll) Ions in Solution

Abstract Polymerization of acrylonitrile initiated by thallium(III) per-chlorate was investigated in aqueous perchloric acid medium in the temperature range 55–70°C. The rate of polymerization was evaluated by varying the concentrations of monomer, initiator, and perchloric acid. The rate of polymerization was found to increase steadily with an increase of monomer concentration. The effect of solvents; micelles of cationic, anionic, and nonionic surfactants; and inhibitors on the rate of polymerization was also studied. Molecular weights and chain lengths of purified polyacrylonitrile were determined by viscometry. The chain transfer constants for the monomer (CM) and that for the solvent dioxane (C) were calculated to be 1.7 × lo4 and 1.6 × lo4, respectively. From the Arrhenius plot, the overall activation energy was found to be 13.2 kcal/mol. A suitable kinetic scheme has been proposed and a rate equation has been derived.

Photoinduced graft copolymerization: XII—Graft copolymerization of methyl methacrylate onto wool using peroxydiphosphate as the photoinitiator

Abstract The photoinduced graft copolymerization of methyl methacrylate onto wool fibers was investigated using peroxydiphosphate as the initiator. Up to a certain concentration of the monomer and the initiator the graft yield increased beyond that concentration a decreasing trend was observed. The reaction was carried out at four different temperatures and the energy of activation was evaluated. The kinetic data and other evidence indicate that the overall polymerization takes place by a radical mechanism. A suitable reaction scheme has been proposed.

Grafting Vinyl Monomers onto Silk Fibers: Graft Copolymerization of Vinyl Monomers onto Silk Using the Vanadyl Acetylacetonate Complex

Abstract The graft copolymerization of methyl methacrylate (MMA) onto mulberry silk fibers was studied in aqueous solution using the acetylacetonate oxovanadium (IV) complex. The rate of grafting was investigated by varying the concentration of the monomer and the complex, the acidity of the medium, the solvent composition of the reaction medium, the surfactants, and the inhibitors. The graft yield increases with increasing concentration of the initiator up to 8.75 × 10−5 mol/L, of the monomer up to 0.5634 mol/L, and thereafter it decreases. Among the various vinyl monomers studied, MMA was found to be most suitable for grafting. Grafting increases with increasing concentration of HCIO4 and with increasing temperature. Inhibitors like picryl chloride and hydroquinone significantly decrease the extent of grafting. Alcoholic solvents at a solvents/water ration of 10:90 seem to constitute the most favorable medium for grafting. A suitable reaction scheme has been proposed, and the activation energy calculate...

Vinyl Polymerization of Ethyl Acrylate Initiated by TI3+-Ascorbic Acid Redox System

Abstract Thallium(III) perchlorate alone was found to be ineffective as an initiator for the vinyl polymerization of ethyl acrylate. However, in the presence of the activator ascorbic acid, the redox system T13+ -ascorbic acid was found to initiate polymerization. The kinetics of polymerization of ethyl acrylate initiated by the T13+-ascorbic acid redox system was investigated in aqueous perchloric acid medium in the temperature range 55–70°C in the presence of oxygen. The rate of polymerization was evaluated by varying the concentrations of ethyl acrylate, T13∗, ascorbic acid, and perchlorid acid. The rate of polymerization was found to increase steadily with an increase of monomer concentration, T13+ concentration, ascorbic acid concentration, and perchloric acid concentration. The effects of additives such as organic solvents, different surfactants, and inhibitors on the initial rate of polymerization were investigated. Molecular weights and chain length of the purified polymer were determined by visco...

Grafting vinyl monomers onto wool fibers: graft copolymerization of methyl methacrylate onto wool using ferric acetylacetonate complex

Abstract The graft copolymerization of methyl methacrylate (MMA) onto native and reduced Indian Chokla wool fibers was studied in aqueous solution using an acetylacetonate complex of Fe(III). Perchloric acid was found to catalyze the reaction. The rate of grafting was investigated by varying the concentration of the monomer and the complex, the acidity of the medium, and the solvent composition of the reaction medium. The graft yield increases with increasing concentration of the initiator and with increasing temperature. An increase of monomer concentration up to 0.5634 mol/L and of the HClO4 concentration up to 0.01 mol/L increases the graft yield. Reduced and oxidized wools were found to be better substrates than untreated, esterified, cross-linked, and trinitrophenylated wools. Among the various monomers studied, MMA was found to be the most active. A suitable kinetic scheme is proposed. From the activation energy data, average molecular weight, and spectral studies, the reactivity of -SH groups, and ...

Graft Copolymerization of Methyl Methacrylate onto Nylon 6 Using Thallium(III) Ions as Initiator

Abstract Graft copolymerization of methyl methacrylate onto nylon 6 was investigated in aqueous perchloric acid medium using thallium(III) ions as initiator. The rate of grafting was evaluated by varying the concentrations of monomer, initiator, acid, and temperature. The rate of grafting was found to increase with an increase of both monomer and initiator concentrations. The graft yield was found to increase with an increase in the acid concentration up to 0.49 mL−1, and beyond this concentration of perchloric acid the graft yield was found to decrease. It also increased with an increase of temperature. From the Arrhenius plot the overall activation energy was found to be 3.9 kcal/mol. The effects of inhibitors, various solvents, inorganic salts, and swelling agents on graft yield were studied. A suitable kinetic scheme has been proposed and a rate equation has been derived.