Graft [partially carboxymethylated guar gum-g-poly N-(hydroxymethyl) acrylamide] copolymer: From synthesis to applications

•A graft copolymer (CMG-g-HMA) was synthesized via free radical polymerization.•TGA data show that the grafted polymer is more thermally stable than pure CMG.•The synthesized graft copolymer can be used as superabsorbent and flocculants.

Graft copolymer of N-(hydroxymethyl) acrylamide with carboxymethylated guar gum was synthesized and the reaction conditions were optimized for better yield using potassium peroxymonosulfate and thiourea as a redox initiator. The optimum reaction conditions for grafting have also been determined by studying the effect of N-(hydroxymethyl) acrylamide, hydrogen ion, peroxymonosulphate, thiourea concentration and carboxymethylated guar gum along with time and temperature. Experimental results show that maximum grafting has been obtained at 1.4 g dm−3 concentration of carboxymethylated guar gum and 16 × 10−2 mol dm−3 concentration of N-(hydroxymethyl) acrylamide. It has been observed that grafting ratio, add on, conversion, efficiency and rate of grafting increase up to 6.0 × 10−3 mol dm−3 of hydrogen ion, 2.4 × 10−3 mol dm−3 of thiourea, 14 × 10−3 mol dm−3 of peroxymonosulphate and 35 °C of temperature. Grafted copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis. Water swelling, flocculating, and metal ion uptake properties of partially carboxymethylated guar gum-g-N-(hydroxymethyl) acrylamide have been determined.