Polymethyl methacrylate-g-carboxy-methylcellulose as an amphiphilic coating material for slow-release fertilizer

In the perspective of preparing coating material of water-soluble fertilizer with controlled and slow-release property, polymethyl methacrylate (PMMA) was grafted from carboxymethyl cellulose (CMC) through in-situ polymerization using potassium persulfate (KPS) as initiator. The prepared copolymers (PMMA-g-CMC) were fully characterized using Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Dynamic light scattering (DLS), X-Ray diffraction (XRD), Brunauer Emmett Teller (BET), Scanning electron microscopy (SEM) and mechanical tensile testing. The molecular weight (Mn) was also evaluated using the size exclusion chromatography (SEC). Next, conventional water-soluble diammonium phosphate (DAP) fertilizer was coated by the prepared copolymers using laboratory rotary drum. The coating effectiveness was evaluated in terms of its uniformity and thickness. The successfully coated nanomaterials significantly delay the release rate of nitrogen (N) and phosphorus (P) in water and soil, compared to their release using uncoated fertilizers. Finally, aerobic biodegradation of the coating agent was also demonstrated.