Controlled release characteristics of methylenebisacrylamide crosslinked superabsorbent polymer for water and fertilizer conservation in agriculture sector

摘要: A series of superabsorbent polymers (SAPs) were synthesized free-radically using hydroxyethyl methacrylate (HEMA), acrylic acid (AA) and its potassium salt, methacrylic acid (MAA) and its potassium salt as monomers, and N,N'-Methylenebisacrylamide (N,N1-MBA) as crosslinker. The synthesized SAPs were evaluated for their chemical structure (FT-IR), thermal stability (TGA/DTG), surface morphology (SEM), and water, fertilizers uptake and release characteristics (swelling and deswelling). A SAP with the optimized composition of monomer and crosslinker had absorbed 898 g/g of water, and 68% of urea and 51% of potash from the 1% corresponding fertilizer solutions. The equilibrium swollen SAP had released the absorbed water completely over 21 days, but only 28% of potash and 43% of urea were released from the fertilizer-loaded SAPs under identical conditions with the same duration of release time. The …