Synthesis, Characterization, and Swelling Behaviors of Poly(acrylic acid-co-acrylamide)/Pozzolan Superabsorbent Polymers

Abstract

This article introduces the design and optimization of a new eco-superabsorbent polymer (SAP) aiming to achieve maximum water absorption. In this study, the incorporation of the natural pozzolan (Poz) as an inorganic filler into a SAP was investigated for the first time. A new type of cross-linker, Bis[2-(methacryloyloxy)ethyl] phosphate, was used in the preparation of SAPs. The Taguchi optimization results revealed that factors’ level of significance on the water absorption are acrylamide (AAm) > acrylic acid (AA) > Poz. The optimum levels of factors that provide maximum water absorption are 30.8% AA, 30.8% AAm, and 38.4% of Poz in total weight. This high percentage of Poz in the optimized SAP is the highest ratio of an inorganic filler to a SAP ever mentioned in the literature. The water absorption capacities of the optimized polymer in ultrapure water and saline water were measured as 11,000 wt% and 2120 wt%, respectively. The overall assessment of FT-IR, XRD, TGA, SEM, and BET studies revealed the successful and homogeneous intercalation of Poz into poly(AA-co-AAm). This new eco-product with enhanced the water absorption capacity and thermal stability can be potentially used as soil conditioners in agricultural activities especially in arid regions.