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

• Published in: Journal of applied polymer science Vol. 110; no. 6; pp. 3455 - 3463
• Main Authors: Mishra, Dinesh Kumar, Tripathy, Jasaswini, Mishra, Madan Mohan, Behari, Kunj
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.12.2008; Wiley
• Subjects: addition polymerization; Applied sciences; Exact sciences and technology; graft copolymerization; Natural polymers; Physicochemistry of polymers; Starch and polysaccharides; swelling; Graft copolymer; Swelling; Property composition relationship; graft copolymerization; Dextran derivatives; Metal ion; Experimental study; Grafting; Thermal stability; Dextran; Thermal properties; Binding capacity; Flocculation reagent; Flocculation; addition polymerization; Pyrrolidone(vinyl) copolymer; Oside polymer; Kinetics
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.28857

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 x 10⁻² mol/dm³. Similarly, when the concentration of hydrogen ion increased, the grafting parameters increased from 3 x 10⁻³ to 5 x 10⁻³ mol/dm³ and attained the maximum value at 5 x 10⁻³ mol/dm³. The grafting ratio, add-on, and efficiency increased continuously with the concentration of peroxydiphosphate increasing from 0.8 x 10⁻² to 2.4 x 10⁻² mol/dm³. When the concentration of thiourea increased from 0.4 x 10⁻² to 2.0 x 10⁻² mol/dm³, the grafting ratio attained the maximum value at 1.2 x 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.