Herein, we report a facile green synthesis of Cu 2 O nanoparticles (NPs) using copper sulfate as precursor salt and hydrazine hydrate as reducing agent in presence of bio-surfactant (i.e. leaves extract of arka -a perennial shrub) at 60 to 70°C in an aqueous medium. A broad band centered at 460 nm in absorption spectrum reveals the formation of surfactant stabilized Cu 2 O NPs. X-ray diffraction pattern of the surfactant stabilized NPs suggests the formation of only Cu 2 O phase in assistance of a bio-surfactant with the crystallite size of ∼8 nm. A negative zeta potential of −12 mV at 8.0 pH in surfactant stabilized Cu 2 O NPs hints non-bonding electron transfer from O-atom of saponin to the surface of NP. Red-shift in the vibrational band (Cu-O stretching) of Cu 2 O from 637 cm −1 to 640 cm −1 in presence of bio-surfactant suggests an interfacial interaction between NPs and O-atoms of -OH groups of saponin present in the plant (i.e. Calotropis gigantea) extract. From X-ray photoelectron spectroscopy spectra, a decrease in binding energy of both 2p 3/2 and 2p 1/2 bands in Cu 2 O with saponin molecules as compared to bulk Cu atom reveals a charge transfer interaction between NP and saponin surfactant molecules. Transmission electron microscopy images show crystalline nature of Cu 2 O NPs with an fcc lattice.

SYNOPSIS Graft copolymerization of methyl methacrylate (MMA) onto wool fibers has been carried out in an aqueous medium under deaerated condition initiated by potassium monopersulphate ( KHS06) /Fe( 111) system, at varying concentration of the reactants and temperature. The effect of various salts and organic solvents on the extent of grafting has also been studied. Maximum graft percentage of 210.8% was obtained in 4 h at 40°C with the concentration of MMA (0.46 M ) , KHS05 (0.0195 M) , Fe( 111) ( 1.25 X M) in the presence of 50% formic acid. Various improved properties of the grafts have been studied and compared with the parent fiber.

We synthesized cuprous oxide (Cu 2 O) nanoparticles (NPs) with an average crystallite size of 8.8 nm in presence of Arka (Calotropis gigantea) leaves extract. The photo-bleaching activity of Cu 2 O NPs on the aqueous methylene blue (MB) dye was studied by illumination of visible light. In the absorption spectra, a decrease in the absorption peak intensity at 665 nm of MB was observed in presence of Cu 2 O NPs. A red shift in its peak position as a function of irradiation time is suggesting that oxide particles are degrading the organic dye in an aqueous medium. In the vibration spectra, red shift in the C-H stretching band (2954, 2926, and 2855 cm -1 ) of methylene group and C-N stretching band (1343 and 1226 cm -1 ) of MB in presence of Cu 2 O NPs proposes a surface adsorption of MB over NP's surfaces. Quenching in the emission band intensity and red shifts in the peak maxima of MB in presence of Cu 2 O NPs is ascribed to the charge transfer interaction between MB and oxide NPs. A linear SternVolmer plot reveals that decrease in the emission intensity of MB dye occurs via the dynamic quenching mechanism. Synthesis of Cu 2 O NPs of various architectures using a green route could be use as an approach towards the costeffective treatment of water pollutants.

SynopsisGraft copolymerization of acrylamide (AM) onto wool fibers has been studied in aqueous solution with a new redox initiating system, KHS05/Fe( 11). For estimation of comparative influence of salts and selection of reaction medium, grafting has also been studied in the presence of a multitude of inorganic salts and some organic solvents. It was observed that the graft percentage was influenced by the reaction time, temperature, concentration of monomer initiator, FeS04, and the base polymer. A maximum graft percentage of 120.5% was obtained a t 35°C with the concentration of AM (0.8 M ) , KHSOB (0.0195 M ) and Fe( 11) (2.5 X M ) for reaction time of 2 h. From the experimental results, a suitable reaction mechanism for graft initiation and termination has been suggested. The water retention of the grafts and their behavior towards mineral acids and alkalis have been tested. The tensile strength and the thermal stability of the grafts have also been determined and compared with the base.

ABSTRACT:Graft copolymerization of acrylic acid onto wool fibers was carried out with quinquivalent vanadium as the initiator in an aqueous medium under nitrogen atmosphere. The percentage of grafting was influenced by reaction time, temperature, concentrations of acid, monomer, initiator and base polymer. Grafting has also been carried out in the presence of various organic solvents. It [V+ 5 ]=0.025 M, Wool =0.2 g and for a reaction time of 6 h. A suitable mechanism has been proposed for graft initiation and termination. A theoretical rate equation has been derived. The behaviour of the graft copolymers towards mineral acids and alkalis has been tested. Their tensile properties, dye-uptake ability and absorption of water and water vapour have also been examined. KEY WORDSDefatted Wool / Initiator Effect / Monomer Effect / Temperature Effect / Solvent Effect / Tensile Modulus / Dye-Uptake / Wool, a natural protein, called oc-Keratin has significant characteristics and is used for making warm garments. With a view to enhance the durability of woolen garments and to add improved properties such as better dyeability, prevention of shrinkage and pilling, improved bacterial resistance, hydroscopicity, tensile strength, thermal stability, etc. attempts have been made since 1945 to modify wool fibers chemically. This involves functionality changes via etherification, esterification, urethanation, amidation, etc. 1 -5 ; by interfacial graft condensation of polyamides, 6 -s polyurethanes,9 polyureas, polyesters, polycarbonates10 via radical grafting of vinyl monomers involving high energy radiation. Photochemical and chemical method of initiation involving metal and non-metal ion initiators" -37 and through chemical treatments.38-51 However, during recent years, * To whom all correspondence should be made. chemical methods of initiation of grafting involving metal and non-metal ion oxidisers, organic peroxides, hydroperoxides, aliphatic azo compounds like ce+4, y+s, Mn(IV), Mn(III), S 2 0~-, HS0 5 , H 2 0 2 , P 2 0~-, BPO, CHP, AIBN, etc. have attracted the attention of chemists as has been reviewed by us recently. 52 Among the chemical initiators quinquivalent V(V) has a unique identity and it is reported to oxidise a multitude of mganic substrates (alcohols, acids, aldehydes, sugars, mercaptanes) in aqueous H 2 S0 4 medium. 53 Most of such reaction proceed through a free radical path that effectively initiates vinyl polymerization. Further, quinquivalent vanadium has similar affinity towards macromolecules contammg characteristic pendant groups (-OH, -CHO, -NH 2 , -SH, --COOH, etc.) on their backbone so that the interactions ofV(V) with the groups form polymer free radicals 883