Fabrication of Biodegradable MOF-Based Composites Using Twin-Screw Extrusion for Sustainable Agrochemical Delivery

Twin-screw extrusion can be used for the large-scale preparation of polymer composites as it reduces the use of harsh solvents, provides better dispersibility of the filler material, shortens production times, and improves scalability, compared to the traditional solvent casting method. This study reports the preparation of MOF-based biodegradable polymer hybrid composite membranes using a vertical co-rotating twin-screw extruder for potential application in the delivery of herbicides. Herein, two MOFs, UiO-66 and UiO-66-NH₂, were synthesized through the solvothermal method and postsynthetically loaded with the three herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), and glyphosate. The herbicide-loaded MOFs were incorporated into polycaprolactone (PCL) at 10, 20, and 30 wt % using twin-screw extrusion. The membranes were characterized using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Mechanical testing revealed that the incorporation of MOFs enhanced the Young's modulus of the PCL composite films. The Young's modulus of the herbicide-loaded MOF-PCL (herbicide@MOF@PCL) composite films increased with increasing percentage of MOFs, as compared to when herbicides were directly loaded into the PCL to prepare the composite films. Herbicide release studies showed that herbicide@MOF@PCL led to sustained release of herbicides. These findings highlight the preparation of MOF-based composite membranes using twin-screw extrusion as an environmentally sustainable and effective method and their potential application in agrochemical delivery.