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Kunj Behari - One of the best experts on this subject based on the ideXlab platform.
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modification of alginate by grafting of n vinyl 2 pyrrolidone and studies of physicochemical properties in terms of swelling capacity metal ion uptake and flocculation
Carbohydrate Polymers, 2010Co-Authors: Arpit Sand, Dinesh Kumar Mishra, Mithilesh Yadav, Kunj BehariAbstract:Abstract The optimum conditions for grafting of N -vinyl-2-pyrrolidone onto alginate initiated by potassium peroxymonosulphate/glycolic acid redox initiator have been determined by varying the concentration of N -vinyl-2-pyrrolidone, hydrogen ion, potassium peroxymonosulphate, glycolic acid, alginate along with time and temperature. Experimental results show that maximum grafting has been obtained at 0.1 g dm −3 concentration of alginate and 16 × 10 −2 mol dm −3 concentration of N -vinyl-2-pyrrolidone. It has been observed that grafting ratio, add on, conversion and efficiency increase up to 5.0 × 10 −3 mol dm −3 of hydrogen ion, 2.8 × 10 −3 mol dm −3 of glycolic acid, 12 × 10 −3 mol dm −3 of potassium peroxymonosulphate and 40 °C of temperature. A physicochemical phenomenon in terms of swelling, metal-ion uptake and flocculation has also been studied and it has been found that graft copolymer shows enhancement in these properties than pure alginate. Both, grafted and ungrafted samples have been characterized by FTIR-Spectroscopy and thermogravimetric analysis.
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graft copolymerization of n vinyl 2 pyrrolidone onto chitosan synthesis characterization and study of physicochemical properties
Carbohydrate Polymers, 2010Co-Authors: Abhishek Srivastava, Dinesh Kumar Mishra, Kunj BehariAbstract:Abstract The optimum conditions for maximum grafting have been determined by varying the concentrations of N -vinyl-2-pyrrolidone, hydrogen ion, potassium bromate, silver nitrate, chitosan along with time and temperature. The grafting ratio increased on increasing N -vinyl-2-pyrrolidone concentration and reaches maximum value at 20 × 10 −2 mol dm −3 . Similarly, the concentration of hydrogen ion increases, the grafting parameters increase and attain maximum value at 1.8 × 10 −2 mol dm −3 . The grafting parameters increase continuously on increasing the concentration of potassium bromate from 2 × 10 −3 mol dm −3 to 10 × 10 −3 mol dm −3 . On increasing silver nitrate concentration from 0.4 × 10 −2 to 3.6 × 10 −2 mol dm −3 , grafting ratio is found to be maximum at 2.8 × 10 −2 mol dm −3 . The grafting parameters decrease continuously on increasing the concentration of chitosan. An attempt has been made to study some of the physicochemical properties in terms of swelling, metal ion sorption and flocculation. The chitosan and chitosan-g- N -vinyl-2-pyrrolidone were characterized by infrared spectroscopy and thermogravimetric analysis.
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modification of dextran through the grafting of n vinyl 2 pyrrolidone and studies of physicochemical phenomena in terms of metal ion uptake swelling capacity and flocculation
Journal of Applied Polymer Science, 2008Co-Authors: Dinesh Kumar Mishra, Jasaswini Tripathy, Madan Mohan Mishra, Kunj BehariAbstract:The optimum conditions for grafting N-Vinyl-2-Pyrrolidone onto dextran initiated by a peroxydiphosphate/thiourea redox system were determined through the variation of the concentrations of N-Vinyl-2-Pyrrolidone, hydrogen ion, potassium peroxydiphosphate, thiourea, and dextran along with the time and temperature. The grafting ratio increased as the concentration of N-Vinyl-2-Pyrrolidone increased and reached the maximum value at 24 × 10−2 mol/dm3. Similarly, when the concentration of hydrogen ion increased, the grafting parameters increased from 3 × 10−3 to 5 × 10−3 mol/dm3 and attained the maximum value at 5 × 10−3 mol/dm3. The grafting ratio, add-on, and efficiency increased continuously with the concentration of peroxydiphosphate increasing from 0.8 × 10−2 to 2.4 × 10−2 mol/dm3. When the concentration of thiourea increased from 0.4 × 10−2 to 2.0 × 10−2 mol/dm3, the grafting ratio attained the maximum value at 1.2 × 10−2 mol/dm3. The grafting parameters decreased continuously as the concentration of dextran increased from 0.6 to 1.4 g/dm3. An attempt was made to study some physicochemical properties in terms of metal-ion sorption, swelling, and flocculation. Dextran-g-N-Vinyl-2-Pyrrolidone was characterized with infrared spectroscopy and thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
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synthesis and characterization of graft copolymer guar gum g n vinyl 2 pyrrolidone and investigation of metal ion sorption and swelling behavior
Journal of Applied Polymer Science, 2006Co-Authors: Arti Srivastava, Kunj BehariAbstract:Graft copolymer of N-Vinyl-2-Pyrrolidone with guar gum was synthesized and its reaction conditions were optimized for better yield using potassium peroxymonosulfate (PMS) and glycolic acid (GA) as a redox initiator. The effect of PMS, GA, hydrogen ions, guar gum, and N-Vinyl-2-Pyrrolidone (NVP) along with reaction time and temperature were studied by determining the grafting parameters: grafting ratio, efficiency, conversion, add-on, homopolymer, and rate of grafting. It was observed that the maximum yield occurred at with a time of 120 min at a temperature of 45°C and a guar gum concentration of 0.4 g/L concentration. The graft copolymer was characterized by infrared spectroscopy and thermal analysis. The activation energy for the grafted and ungrafted gum was calculated. It was observed that the graft copolymer was thermally more stable than the pure gum. The swelling and metal ion sorption behavior of guar gum and guar gum-g-N-Vinyl-2-Pyrrolidone also were studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2480–2489, 2006
Jilin Tang - One of the best experts on this subject based on the ideXlab platform.
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a facile one pot method to high quality ag graphene composite nanosheets for efficient surface enhanced raman scattering
Chemical Communications, 2011Co-Authors: Zhe Zhang, Wenshu Yang, Mingyi Guo, Xiaodan Wang, Bailin Zhang, Jilin TangAbstract:Ag-graphene composite nanosheets (AGCN) with adjustable size and well-controlled densities of Ag nanoparticles (Ag NPs) using Poly(N-Vinyl-2-Pyrrolidone) (PVP) as a reductant and stabilizer are reported. The obtained AGCN substrate is extremely suitable for surface-enhanced Raman spectroscopy (SERS).
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a facile one pot method to high quality ag graphene composite nanosheets for efficient surface enhanced raman scattering
Chemical Communications, 2011Co-Authors: Zhe Zhang, Wenshu Yang, Xiaodan Wang, Bailin Zhang, Fugang Xu, Jilin TangAbstract:Ag-graphene composite nanosheets (AGCN) with adjustable size and well-controlled densities of Ag nanoparticles (Ag NPs) using Poly(N-Vinyl-2-Pyrrolidone) (PVP) as a reductant and stabilizer are reported. The obtained AGCN substrate is extremely suitable for surface-enhanced Raman spectroscopy (SERS).
Malcolm A Kelland - One of the best experts on this subject based on the ideXlab platform.
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first investigation of the kinetic hydrate inhibitor performance of polymers of alkylated n vinyl pyrrolidones
Energy & Fuels, 2013Co-Authors: Fernando T Reyes, Malcolm A KellandAbstract:A series of water-soluble homopolymers and copolymers of 1-alkyl-vinyl pyrrolidones (1-alkyl-VPs) with alkyl groups, including methyl, ethyl, isopropyl, and n-propyl, has been synthesized. Homopolymers with larger alkyl groups had cloud points in water lower than 0 °C. The comonomers used in the copolymers were N-vinyl pyrrolidone (VP) and N-methyl-N-vinyl acetamide (VIMA). The performance of the water-soluble 1-alkyl-VP polymers as kinetic hydrate inhibitors was investigated for the first time. Tests were conducted in high-pressure rocking cells using a structure II hydrate-forming natural gas mixture and compared to poly(N-vinyl lactam)s of similar molecular weight. The best copolymer of this series was the 1:1 nPr-VP/VIMA copolymer. 1-dimethyl-VP and 1-ethyl-VP homopolymers and the 1:1 n-propyl-VP/VP copolymer also showed better performance than poly(N-vinyl caprolactam) and poly(N-vinyl azocyclooctanone) of similar molecular weights. The structure–performance analysis in this study suggests that a mor...
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first investigation of the kinetic hydrate inhibitor performance of polymers of alkylated n vinyl pyrrolidones
Energy & Fuels, 2013Co-Authors: Fernando T Reyes, Malcolm A KellandAbstract:A series of water-soluble homopolymers and copolymers of 1-alkyl-vinyl pyrrolidones (1-alkyl-VPs) with alkyl groups, including methyl, ethyl, isopropyl, and n-propyl, has been synthesized. Homopoly...
Magdalena Tarnacka - One of the best experts on this subject based on the ideXlab platform.
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the application of spatially restricted geometries as a unique route to produce well defined poly vinyl pyrrolidones via free radical polymerisation
Chemical Communications, 2019Co-Authors: Magdalena Tarnacka, Paulina Maksym, Andrzej Zieba, Anna Mielanczyk, Monika Geppertrybczynska, Laia Leonboigues, Carmen Mijangos, K Kaminski, M PaluchAbstract:We report, for the first time, the metal-free green synthesis of linear poly(vinyl pyrrolidone) (PVP) homopolymers of molecular weight higher than 100 kg mol-1 and narrow dispersities via thermal and photo-induced free radical polymerisation carried out within alumina nanoporous membranes acting as "nanoreactors".
Sijia Li - One of the best experts on this subject based on the ideXlab platform.
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kinetic hydrate inhibitor performance of new copolymer poly n vinyl 2 pyrrolidone co 2 vinyl pyridine s with tbab
Journal of Natural Gas Chemistry, 2012Co-Authors: Sijia LiAbstract:Abstract In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs' inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-Vinyl-2-Pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6 °C. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.
