Capability lignin from Acacia crassicarpa black liquor as an environmentally benign antibacterial agent to produce antibacterial and hydrophobic textiles

Recently, the growing health awareness of society on the utilization of fabrics has led to an increasing demand for natural-based antibacterial textiles. Lignin, a generous polyphenol compound in nature, is capable of preventing bacterial growth; in particular, it dwells bacteria closely together on human skin, such as Staphylococcus epidermidis, Bacillus subtilis, Propionibacterium acnes, and Staphylococcus aureus. However, the antibacterial properties of lignin are limited by factors such as the lignin concentration, source, and type of bacteria. This study aimed to evaluate the potency of lignin as an antibacterial agent for textiles. Moreover, the thermal properties and wettability of the textile after lignin coating were also investigated. This study showed that lignin isolation methods significantly contributed to the inhibition of bacterial growth in the clear zone diameter. In addition, the lignin structure, lignin concentration, and type of bacteria had notably different antibacterial effects. SEM images showed that lignin was successfully coated on the fiber, and the antibacterial textile was successfully fabricated with clear zones in the range of 0.1–0.5 cm against four different bacteria. Lignin did not significantly improve the thermal stability of the textile, as proven by the TGA results. After the HDTMS coating by dispersion method, the wettability of the lignin-textile improved to that of the hydrophobic material, with a contact angle greater than 119.05° with excellent antibacterial properties (clear zone of 0.1–0.43 cm).