High performance and low cost composite superabsorbent based on polyaspartic acid and palygorskite clay

A high performance and low cost composite superabsorbent (PAsp-g-PAA/PGS) based polyaspartic acid (PAsp) and palygorskite (PGS) clay is successfully prepared by free-radical polymerization grafting poly acrylic acid (PAA) in aqueous solution. Elemental map, scanning electron microscopy and the Fourier transform infrared analyses reveal the palygorskite evenly distributed and grafted onto PAsp-g-PAA matrix. Thermogravimetric/differential thermal analysis confirmed that the composite superabsorbent has high thermal stability. Furthermore, we investigated the affects of pH values and salts to the swelling and water-retention capability of the composite superabsorbent. The composite superabsorbent exhibits high water absorbency (1405 g/g in distilled water), pH-stability (pH 6-10) and salt tolerance (93 g/g in 0.9 wt.% salt solution). All of these properties of the composite superabsorbent make wider applications in agriculture, horticulture and wastewater treatment.