Synthesis of Partially Hydrolyzed Graftcopolymer Based Superabsorbent

Gellan Gum (GG) was modified with N-vinyl Formamide (NVF) through PDP/Ag + redox system initiated graft copolymerization in a thermostatic water bath at 35°C under nitrogen atmosphere. The highest percentage of grafting (186%) and the lowest homopolymer content (22.2%) were achieved through a systematic optimization of the polymerization variables, including reaction time, temperature, and concentration of PDP, Ag + , NVF and the gum. Evidence of grafting was examined by comparing FTIR spectra. The optimally prepared graftcopolymer (GG-g-NVF) was also characterized thermally and morphologically. The GG-g-NVF product was saponified using sodium hydroxide aqueous solution to prepare a partially hydrolyzed graft copolymer based superabsorbent, H-GG-g-NVF. The effect of dewatering agent of H-GG-g-NVF on water absorbency has been studied. The percentage swelling of H-GG-g-NVF in various ionic salt (NaCl, CaCl2 and AlCl3) solutions were investigated. In addition, the percentage swelling changes of H-GG-g-NVF at different pHs solutions has been also studied. Keywords—Gellan gum, N-vinylformamide, partially hydrolyzed graft copolymer, thermogravimetric analysis