Novel molasses-grafted poly(sodium acrylate) hydrogel: A sustainable solution for water retention and controlled dinotefuran release

Abstract

Sugarcane molasses, a byproduct derived from sucrose manufacturing, is a polyphenolic compound with high sugar content. In this study, a novel molasses-grafted poly(sodium acrylate) hydrogel (M-g-SAH) is synthesized via free radical co-polymerization, using potassium persulfate (KPS) as the initiator and N,N’-Methylenebisacrylamide (MBA) as the crosslinker. M-g-SAH is characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and rheometer. Results demonstrated significant structural, thermal, and morphological changes in M-g-SAH compared to the non-grafted control hydrogel (ctrl). Swelling studies in Milli-Q water revealed that M-g-SAH achieved a maximum swelling index of 225.9 g g^-1, with swelling behavior influenced by molasses, KPS, and MBA concentrations. The controlled release of molasses from the M-g-SAH is modelled using Korsmeyer-Peppas, Higuchi, and first-order kinetics. M-g-SAH demonstrated a prolonged release of molasses over 39 h, outperforming the ctrl. According to ANOVA results, the addition of molasses proved to be an effective factor in agricultural trials, as the M-g-SAH hydrogel significantly showed improved water retention and reduced evaporation rate compared to ctrl. Additionally, dinotefuran loading and release studies confirmed M-g-SAH's potential as a pesticide carrier, supporting sustained release applications. These properties make M-g-SAH an eco-friendly and versatile material suitable for agricultural applications.