Castor Oil-Derived Ionic Liquids for Flexible, Antibacterial Biobased Thermosetting Polymers via Thiol-Ene Click...

The escalating threat of bacterial infections highlights the urgent need for flexible antibacterial biobased resin materials. In this study, castor oil was transformed into imidazole-based ionic liquids (c1 and c2) via a two-step atom-economic synthesis. Thermosetting resins were fabricated through UV-thermal dual-cured thiol-ene click polymerization of c1/c2 with multifunctional thiol monomers. A biobased aromatic α,ω-diene carbonate monomer (d) was introduced to modulate the network structure. Thermal curing behavior was optimized by using NMR and FTIR analyses. Tensile testing identified Pc1₁d₉-4SH and Pc2₁d₉-4SH as optimal formulations, exhibiting tensile strengths of 9.42 and 9.08 MPa, elongation at break of 279.9% and 280.0%, and a glass transition temperature around 15 °C. DMA and TGA confirmed their viscoelastic behavior and thermal stability, while AFM/SEM revealed phase-separated microstructures contributing to enhanced mechanical properties. Antibacterial tests demonstrated exceptional efficacy (99.9% inhibition) against common pathogens. By integrating molecular design and process innovation, this work establishes a biobased resin system combining flexibility, thermal stability, and potent antibacterial activity, offering a novel strategy for developing infection-resistant biomedical materials.