Sustained-release microsphere formulation containing an agrochemical by polyurethane polymerization during an...

Area of Science:

• Polymer Chemistry
• Materials Science
• Agricultural Chemistry

Background:

• Neonicotinoid insecticides like clothianidin (CTD) are vital for pest control.
• Developing controlled-release formulations enhances insecticide efficacy and reduces environmental impact.
• Polyurethane (PU) offers potential for microencapsulation due to its tunable properties.

Purpose of the Study:

• To develop a novel solventless microencapsulation technique for CTD using polyurethane.
• To characterize the physical properties and release kinetics of the developed CTD microspheres.
• To investigate the structural integrity and release mechanisms of the microspheres.

Main Methods:

• Solventless synthesis of PU via polyol and isocyanate agglomeration in a high-speed mixer.
• Microencapsulation of clothianidin (CTD) within the PU matrix to form CTD microspheres.
• Analysis using synchrotron X-ray computed tomography (CT) and release studies.

Main Results:

• Developed CTD microspheres with a median diameter <75μm and sustained-release properties.
• Synchrotron X-ray CT revealed dispersed CTD cores within the PU matrix.
• Microspheres maintained spherical shape and structural integrity post-release, with voids forming.
• Release data aligned with the Baker-Lonsdale model, indicating predictable release kinetics.

Conclusions:

• The developed solventless PU microencapsulation method is effective for sustained release of CTD.
• The microspheres exhibit excellent structural stability and predictable release profiles.
• This technique offers a promising approach for advanced insecticide formulations.