Optimization of biodegradable cross-linked guar-gum-PLA superabsorbent hydrogel formation employing response surface methodology

Cross-linked polymer networks with three-dimensional structures known as hydrogels absorb and retain a large amount of water. Because of their properties, hydrogel materials have been considered a boon in agriculture science. In the present investigation, guar gum cross-linked polylactic acid hydrogel is synthesized using MMA as monomer and optimized using a central composite design of response surface methodology for better swelling. The studied input variables are monomer concentration, initiator concentration, and cross-linker concentration at constant pH and temperature. The constructed response model has been tested using the analysis of variance (ANOVA), where the model F-value of 4.64 indicates that the model is significant. The R2 value (0.806) (multiple correlation coefficient) and the standard deviation for the quadratic model were both found to be 4.27. A separate validation experiment is conducted to ensure the quadratic model is sufficient. The hydrogel synthesis was confirmed by characterization techniques like FTIR spectroscopy, SEM, TGA, XRD, and water absorption studies. Synthesized hydrogels swell maximum in water and least in 0.9 % NaCl solution. The present work highlights the development of guar gum-based super-absorbent hydrogels, which are biodegradable and lead to potential application in agriculture, especially in drought regions.