Ali Akbar Zolriasatein *
In this study, jute yarns were treated with laccase enzyme in different treatment times and ultrasonic powers. Lower whiteness index and higher yellowness index values were obtained by laccase-ultrasound system in contrast to conventional laccase treatment. The laccase enzyme which entered the fibers, by applying ultrasound, decreased the tensile strength while the loss in tensile strength was lower at high ultrasound intensities. FT-IR spectrum showed that the band at 1634 cm-1 assigned to lignin was completely disappeared after enzymatic treatment with laccase in the presence of ultrasound. Change in morphology of fibers was observed by SEM before and after enzymatic delignification. The laccase-ultrasound treated yarns showed rougher surface and more porosity. On the other hand, it was more effective in fibrillation of the jute fibers than conventional method. Finally, bio-treated jute yarns were dyed with basic and reactive dyes. The results indicated that at low intensities of ultrasound and relatively long reaction times lignin can be more effectively removed and dye strength (K/S) increased to a higher extent. In the case of light fastness, the conventional laccase treated yarns provided better protection than laccase-ultrasound treated yarns.
jute, laccase enzyme, ultrasound, whiteness, brightness, dyeing
Department of Textile Engineering, College of Technical and Engineering, Yadegar-e-Imam Khomeini (RAH) shahre-rey Branch, Islamic Azad University, Tehran