Superabsorbent hydrogels prepared from waste polystyrene and linear low-density polyethylene

Superabsorbent hydrogels, polystyrene-graft-polyacrylic acid (PAA; PS- g-PAA), linear low-density polyethylene (LLDPE)-graft-PAA (LLDPE- g-PAA), and hydrogel composites, PS- g-PAA/bentonite (BT), were synthesized through emulsion polymerization using acrylic acid as a monomer, benzoyl peroxide as an oil-soluble initiator, and ammonium persulfate and sodium sulfite as a redox initiator in the presence of N, N-methylenebisacrylamide as a cross-linking agent. The superabsorbents were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The maximum water absorbencies for PS- g-PAA and PS- g-PAA/BT were 780 and 900 g g −1 in distilled water, respectively, while the water absorbency of LLDPE- g-PAA superabsorbent was 450 g g −1 in distilled water.