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.