Swapna Kudal1,2* Oliver Gutsche1, Zhibing Zhang2, Christropher Windows-Yule2, Sergiy Peleshanko1*
1Stine Research Centre-FMC, Newark, Delaware,USA
2School of Chemical Engineering, University of Birmingham,Birmingham, UK
*Corresponding author’s E-mail:smk278@student.bham.ac.uk, Sergiy.Peleshanko@fmc.com
Abstract
In response to the European Union's regulations mandating the elimination of non-biodegradable capsule materials in pesticide formulations, this project endeavours to develop biodegradable chemistry using interfacial polymerization methods. The objective is to develop biodegradable core-shell capsule formulations while ensuring compliance with regulatory standards. Through an exploration of environmentally friendly monomers and polymerization chemistries, we seek to characterize capsule reaction chemistry, optimize reaction kinetics, assess capsule properties, and evaluate permeability, curing processes, and stability. The research targets specific biodegradable chemistries tailored for microencapsulation in agrochemical applications, advancing the field towards sustainable agricultural practices. Through systematic experimentation, parameter windows are established to optimize yield and kinetics, laying the foundation for scalable production. This work focuses on developing and comparing biodegradable polyurethane (PU) and polyurea (PUa) capsules for controlled AI release. A biodegradable ester-based isocyanate was synthesized in-house and confirmed using FTIR, NMR, and mass spectrometry. Using interfacial polymerization, this isocyanate was reacted with biodegradable diols (for PU) and amines (for PUa) to form capsule shells. Capsules were studied using difference characterizations such as optical microscopy, SEM, particle size analysis, etc. Thermal properties were measured using TGA and DSC, while micromanupulation/ compression twere used to assess mechanical strength. We also evaluated encapsulation efficiency and release kinetics to understand pearmeability and diffusion mechanism. Reaction kinetics showed differences between PU and PUa systems due to the reactivity of ester-based isocyanates with diols versus amines. Biodegradability tests under controlled conditions showed faster breakdown for PUa capsules, while PU capsules showed better thermal and mechanical stability. Overall, the study highlights the strengths and trade-offs between PU and PUa systems and provides useful guidance for designing sustainable, high-performance agrochemical delivery capsules.
References
[1] Woźniak-Budych, M. et al. (2024) ‘Microplastic label in microencapsulation field – Consequence of shell material selection’, Journal of Hazardous Materials.
[2] Perignon, C., Ongmayeb, G., Neufeld, R., Frere, Y., & Poncelet, D. (2014). Microencapsulation by interfacial polymerisation: membrane formation and structure, Journal of Microencapsulation
[3] Serra, C. A., Cortese, B., Khan, I. U., Anton, N., de Croon, M. H. J. M., Hessel, V., Ono, T., & Vandamme, T. (Year). Coupling Microreaction Technologies, Polymer Chemistry, and Processing to Produce Polymeric Micro and Nanoparticles with Controlled Size, Morphology, and Composition, MacromolecularJournals