Chemical-Free and Functional Dyeing of Cotton Fabric with Khaya anthotheca Bark Extract: A Natural Dye with Antimicrobial Activity
摘要
In recent decades, growing environmental concerns have heightened interest in exploring various natural dye sources. Chemical-free dyeing has also become a sustainable alternative to conventional dyeing that avoids using chemicals. This study investigates the use of Khaya anthotheca bark, known for its high tannin content, for dyeing 100% cotton fabrics, as dyestuff containing tannin effectively binds with fibers to provide color fixation without using mordants. The cotton fabrics were dyed using the aqueous extract in the exhaust method at 90 °C for 60 min. The colorimetric attributes of the dyed samples, specifically color strength (K/S), and color variations were assessed using a spectrophotometer. The increase in K/S values from 1.1 at a 1:20 m:L ratio to 1.7 at a 1:50 m:L ratio demonstrates enhanced color depth as liquor volume increases. The color difference value (ΔE*) increased from 24.71 to 28.99, which also indicates a perceptible enhancement in color. FTIR spectroscopy suggested the presence of tannin in the dyed fabric, as there has been a shift of peak from 3305 cm−1 to 3301 cm−1, representing the O–H stretching. The color fastness test against wash and perspiration demonstrated a very good to excellent rating. Moreover, the antimicrobial efficacy of dyed fabric was evaluated, and the dyed fabric demonstrated a 97.4% reduction in bacterial count compared to the undyed samples. Overall, the findings indicate that the Khaya anthotheca wood bark extract can serve as an effective dye source for chemical-free dyeing of cotton fabric, reducing adverse impact on the environment.
Graphical Abstract