Analysis of antifungal properties of Ferula asafoetida extract as biocides in wood polyurethane coatings

Coatings are widely applied to protect wood from hygroscopicity, flammability, biological degradation, and surface weathering. Weathering, a surface phenomenon, significantly impacts the appearance, service life, and performance of wood coatings. Over time, external factors degrade coating performance. This study examines how Ferula asafoetida essential oil improves polyurethane (PU) coatings. GC-MS analysis identified 26 major compounds in the oil, with (E)− 1-propenyl sec-butyl disulfide (39.14%) as the most abundant. The essential oil was mixed with water-based PU (0.5%) and applied to beech and pine wood surfaces. Coating performance was evaluated through fungal resistance, mold growth, discoloration, and adhesion tests, both before and after weathering. Results showed that the essential oil-enhanced PU coating (PU + E) exhibited significantly improved fungal and mold resistance compared to PU and control samples. Although the functionality of PU + E coatings diminished over time, they remained superior to untreated samples after aging. Weathering induced substantial color changes in both coated and uncoated samples. Adhesion tests revealed that the PU + E coating adhered better to beech than pine wood. Essential oil did not affect coating strength initially, but PU + E coatings performed better than PU after weathering.