Fecha de publicación: -- Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Rice-straw lignin is added to an epoxidized soybean oil–divanillic acid vitrimer platform that combines corrosion protection with structural adhesion. The optimized formulation maintains high low-frequency impedance after 30 days, shows thermally assisted partial barrier and scratch recovery, and retains approximately 89% lap-shear strength after three rebonding cycles, highlighting multifunctional dynamic-network performance.

ABSTRACT
This study examines bio-based epoxy–ester vitrimer networks prepared from epoxidized soybean oil (ESO), divanillic acid (DVA), and rice-straw lignin obtained by ultrasound-assisted alkaline treatment. The COOH/epoxy ratio (0.7–1.5) and lignin loading (0–30 wt%) were varied to relate formulation, exchange dynamics, coating performance, and adhesive reusability. For ESO–DVA–1.0–L20, the coating showed a pull-off adhesion of 9.69 ± 0.12 MPa, 182 ± 18 MEK double rubs, and a minimum mandrel diameter of 4.43 ± 0.71 mm. After 30 days in 3.5 wt% NaCl, |Z| at 0.01 Hz was approximately 1.0 × 109 Ω cm2, compared with approximately 8.2 × 108 Ω cm2 for the lignin-free analogue. Thermal treatment at 200°C for 1 h increased |Z| at 0.01 Hz from approximately 2.5 × 107 to 2.0 × 108 Ω cm2, corresponding to approximately 13% of the intact-coating value (approximately 1.5 × 109 Ω cm2). Optical microscopy, SEM, and 3D profilometry further showed reductions of 37.5% in scratch width and 44.4% in scratch depth, confirming partial rather than complete damage recovery. The same formulation reached an initial lap-shear strength of approximately 14.7 MPa and retained approximately 89% after three rebonding cycles; its Mode-I fracture energy was approximately 1.36–1.56 kJ m−2.