Synthesis of bio-based polymeric hydrogels from a hybrid system of cellulose derived from selected invasive plant biomass grafted with poly(acrylic acid)

The current study presented upcycling invasive plant biomass into high-purity cellulose, which offers a simultaneous solution for ecological management and sustainable production of bio-based materials. The preliminary proximate and lignocellulosic characterization for the biomass was carried out, while polyacrylic acid (PAA) was grafted via free radical polymerization onto the extracted cellulose from parthenium weed (PW) and water hyacinth (WH). The study revealed hemicellulose, lignin, and cellulose in PW to be 41.21%, 18.78%, and 31.13%, while WH has a value of 38.7%, 15.91% and 27.8%. The cellulose displayed a fibrous morphology with increased roughness compared to the amorphous sponge-like structure of pristine PAA. The cellulose exhibited functional groups characteristic of glucose, while PAA hydrogels contained hydrophilic groups (OH and COOH), enhancing water absorption. Thermal analysis indicated that the hydrogel's thermal stability improved with added cellulose. Among the formulations, PAA grafted onto 1% WH and PW-cellulose has the highest absorbency value of 95.43 and 89.46 g/g at 60 minutes, respectively, compared to pristine hydrogel (106.14 g/g). Also, the conditions for maximum water absorbency were observed at a pH of 7, a crosslinker amount of 0.05 g, and an initiator value of 0.010 g. The absorbency value increased to 95.47 g/g for PAA grafted to 1%PW-cellulose. Thus, the study revealed an effective strategy to convert invasive plant-derived cellulose and polyacrylic acid into valuable bio-based hydrogels, promoting material innovation consistent with circular economy and environmental sustainability principles. • Green cellulose extraction from lignocellulosic invasive plant biomass • Fabrication of polyacrylic acid grafted with cellulose biopolymer as a hybrid bio-based hydrogel • Instrumental characterization of fabricated bio-based hydrogels • Absorbency performance of the fabricated bio-based hydrogels