MOF-Modified Biobased Polyol Derived from a Castor-Coated Fertilizer for Precise Controlled Release of Nutrients

Most traditional coating materials of controlled-release fertilizers are from petrochemical products, which are nonrenewable and cause many byproducts, which lead to low resource utilization rates and high costs. It is important to prepare biobased coated controlled-release fertilizers to replace petrochemical membrane materials. Polyurethane controlled-release fertilizers derived from castor oil are faced with challenges such as limited controlled-release performance and unadjustable membrane pore size and are not conducive to accurate controlled release. To address these issues, a kind of porous material─metal organic framework (MOF)─was used to modify the biobased membrane, preparing an accurately controlled-release fertilizer. Compared with the biobased coated controlled-release fertilizer (BCF), the surface of the ZIF-8-modified BCF (MBCF) is smoother and denser, and the hydrophobicity is obviously increased. The increase in the hydrophobic angle from unmodified 106.86 to modified 138.2 delays moisture entries and improves the controlled-release performance of the fertilizer. Compared with unmodified biobased polyurethane-coated controlled-release fertilizer (BCF), the controlled-release fertilizer period was extended to 112 days after 1.5 wt % ZIF-8 modification of MBCF-3. Thus, the MBCF holds significant potential for enhancing the hydrophobicity of fertilizers and enabling precise nutrient release, and it also has broad application prospects for the advancement of fertilizers.