Bio-based Polyurethane Based on a Dynamic Covalent Network with Damage Tolerance for Controlled Release of...

Area of Science:

• Materials Science
• Polymer Chemistry
• Agricultural Science

Background:

• Bio-based polyurethanes (BPU) show potential for controlled nutrient and fertilizer release.
• Existing BPU materials require improvements in toughness and plasticity for practical applications.

Purpose of the Study:

• To develop a robust and high-performance bio-based polyurethane coating for controlled-release fertilizers.
• To enhance the mechanical properties and nutrient release efficiency of BPU coatings.

Main Methods:

• A one-step reaction involving soybean oil polyols (>60%), isocyanate, and benzil dioxime was employed.
• A dynamic covalent network based on oxime-carbamate was introduced to replace irreversible covalent cross-linking.
• The modified coating's dynamic fracture-bonding reaction was analyzed for its effect on structural integrity.

Main Results:

• The developed BPU coating demonstrated approximately 150% superior nutrient controlled release compared to the original BPU.
• Tensile strength was enhanced by approximately 300%, and toughness increased by approximately 1200%.
• The dynamic network effectively prevented structural defects during coating and fertilizer application.

Conclusions:

• A simple and versatile strategy for creating advanced controlled-release fertilizer coatings using bio-based polyurethanes was established.
• The modified BPU offers significantly improved mechanical properties and controlled release capabilities.
• This approach provides a promising solution for sustainable agricultural practices.