Synthesis of bio-based internal and external cross-linkers based on tannic acid for preparation of antibacterial superabsorbents

Recent researches focus on the synthesis of new cross-linkers from natural resources. In the current work, functionalized tannic acid was employed as a replacement of petroleum-based cross-linkers because of its outstanding biochemical properties. Alkene- and epoxy-functionalized tannic acids were synthesized as internal and external cross-linkers, respectively. Cross-linker structures were characterized with Ft-IR and (HNMR)-H-1 analysis. Different amounts, as well as different numbers of alkene functional group, were incorporated during the superabsorbent synthesis. Moreover, the internal cross-linked superabsorbent was surface cross-linked with different amounts of epoxy-functionalized tannic acid and increased the absorbency under load about 10 g g(-1). Free absorption properties in water and saline solution, absorbency under load, and rheological properties of superabsorbents were investigated. In addition, the antibacterial activity of the internal and external cross-linked superabsorbent was studied against Escherichia coli and Staphylococcus aureus bacteria via different methods and compared with that of conventional superabsorbent.