Dyeing Properties of Berberine on Cationic Dyeable Polyester

The natural cationic colorant berberine was used to dye cationic dyeable polyester (CDP) fibers. Its dyeing properties, namely color strength (K/S) of dyed CDP and percent exhaustion (E%) of berberine, on CDP were explored at various dyeing pH levels, temperatures, time, and concentration of berberine. Furthermore, dyeing kinetic and thermodynamic studies were also carried out to evaluate the adsorption properties and mechanism. It was found that the E% of berberine on CDP fibers and the rate of adsorption increased with increasing dyeing temperature, while the influence of pH was extraordinarily small. In addition, the adsorption isotherm of berberine on CDP fibers was in line with the Langmuir model.