Characterization of slow-release collagen-g-poly(acrylic acid-co-2-acrylamido-2-methyl-1-propane sulfonic acid)–iron(III) superabsorbent polymer containing fertilizer

A novel, slow-release polymer containing phosphorous fertilizer was synthesized by the rapid coordination of iron ions with polymers after the microwave radiation polymerization of collagen, 2-acrylamido-2-methyl-1-propanesulfonic acid, and acrylic acid. We obtained an optimized collagen-g-poly(acrylic acid-co-2-acrylamido-2-methyl-1-propane sulfonic acid) collagen-g-p(AA-co-AMPS)–Fe(III) polymer with great equilibrium swelling capacities of 2595 g/g in distilled water and 121 g/g in 0.9 wt % NaCl solution and an excellent sustained fertilizer release of about 30 days. In addition, for the collagen-g-p(AA-co-AMPS)–Fe(III) polymer, the effect of cations on its swelling followed the order K⁺ > Na⁺ > Mg²⁺ > Ca²⁺. The structure and morphology were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Moreover, the collagen-g-p(AA-co-AMPS)–Fe(III) polymers emancipated the nutrients in a more controlled manner than collagen-g-p(AA-co-AMPS). The thermal stability, water absorbency, and good slow-release of fertilizer provide the collagen-g-p(AA-co-AMPS)–Fe(III) polymer with great potential as a fertilizer-carrying vehicle and an aquasorb to be applied in agriculture and horticulture. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47178.