Synthesis of superabsorbent composite based on chitosan-g-poly(acrylamide)/attapulgite

Abstract

The production of environmentally friendly SAP using biodegradable natural resources such as chitosan was synthesized for water saving and controlled-released fertilizer. Chitosan-g-poly(acrylamide)/attapulgite superabsorbent composites (CTS) were created by crosslinking N,N'-methylene-bis-acrylamide (MBA) with chitosan (Ch), acrylamide, and attapulgite (ATP) and initiating the reaction with potassium persulfate (KPS). Spectroscopic techniques such as Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and scanning electron microscope were used to characterize the composite structures. It was done to determine how certain characteristics, such as the initiator percentage, crosslinker ratio, and clay content, affected the composite's ability to swell. The results confirmed that the thermal stability of the composite was improved by the addition of ATP. The maximum swelling was attained when the KPS concentration was 0.1 g. However, the addition of 0.2 g of KPS created a composite with a lower swelling capacity. When the amount of ATP was increased by up to 0.4 g, the swelling increased from 210 to 319 g/g. However, as the clay amount was increased further to 1.2 g, the swelling capacity decreased to 170 g/g. As pH increased to 3.0, the swelling of ATP2 grew larger; nevertheless, it shrank between pH values of 3 and 6. As the pH climbed to 8, the swelling sharply grew. The chosen composition was evaluated as a controlled-release method for urea fertilizer and swelled to 319 g/g in water (CTS2). The findings demonstrated that when the formulation's ATP content was increased from 0 to 1.2 g, the release rate was delayed, and the release length increased from 5 to 21 h.Graphical abstract