Synthesis, Characterization and Study of Metal Ion Sorption Capacity and Water Swelling Behavior of Xanthan Gum‐g‐N,N′‐Dimethylacrylamide

In the present paper Xanthan gum‐g‐N,N′‐dimethyl acryl amide was synthesized by free radical polymerization using a bromate/thiourea redox pair in an inert atmosphere. Studies are done to observe the effect of reactants on grafting parameters by varying the reactant concentration and to study some physical‐chemical properties. Grafting ratio, add on and conversion show a decrement on increasing the concentration of Xanthan gum. The grafting parameters increase on increasing the concentration of N,N′‐dimethyl acrylamide from 8.3×10⁻² to 20×10⁻² mol dm⁻³, BrO₃ ⁻ from 1×10⁻³ to 5×10⁻³ mol dm⁻³ and thiourea from 1.2×10⁻³ to 3.6×10⁻³ mol dm⁻³. Optimum temperature and time for grafting of N,N′‐dimethyl acrylamide on Xanthan gum are found to be 35°C and 120 min, respectively. Water swelling behavior, swelling ratio, and metal ion uptake, metal retention capacity are also studied. It was found that the graft copolymer shows a greater enhancement in these properties than the substrate. The graft copolymer is characterized by FTIR and thermal analysis.

Keywords:

• xanthan gum
• graft copolymer
• thermal analysis
• bromate/thiourea redox pair
• N,N′‐dimethyl acrylamide
• metal ion uptake
• water swelling behavior