Tailoring bio-based polyurethane durable wood coating from linoleic acid methyl ester polyol: a comparative assessment of aromatic and aliphatic isocyanate networks

In this study, a polyurethane wood coating was synthesized using a linoleic acid methyl ester polyol (LP) prepared via epoxidation and ring-opening of linoleic acid methyl ester (LAME). The physicochemical properties of the synthesized polyol were evaluated by refractive index, specific gravity, and hydroxyl value measurements, while the successful synthesis of LP and polyurethane was confirmed by FTIR, ¹H NMR, and ¹³C NMR analyses.

Polyurethane coatings prepared using aromatic MDI and aliphatic HDI were evaluated for thermal stability, morphology, wettability, adhesion, hardness, chemical resistance, and antibacterial activity. The MDI-based coating exhibited higher thermal stability, with a maximum degradation temperature of 502°C compared to 472°C for the HDI-based coating. Both coatings exhibited antibacterial activity against <i>Staphylococcus aureus, Bacillus cereus</i>, and <i>Escherichia coli</i>, with the highest inhibition observed against <i>Staphylococcus aureus</i> and the lowest against <i>Escherichia coli</i>.