Sonication induced effective approach for coloration of compact polyacrylonitrile (PAN) nanofibers

We present our research on dyeability of polyacrylonitrile (PAN) nanofibers following ultrasonic dyeing method. Although PAN has been extensively utilized in textile apparel, sportswear, upholstery and home furnishing, however, coloration of PAN nanofibers has not yet been reported. PAN is a compact fiber while the nanofiber structure makes it more difficult to color PAN nanofibers. PAN is generally dyed with basic dyes and dyeing is carried out in acidic conditions, while the dyeing process takes about two hours at boiling temperature. A systematic study on dyeability of PAN nanofibers will extend its use in textile apparel industry. Thus, we used ultrasonic energy and first time conducted our research on dyeability of electrospun PAN nanofibers using disperse dyes. Dyeing process parameters such as dyeing time, temperatures and concentrations of dyes were optimized. Ultrasonic dyeing of PAN nanofibers was compared with its conventional dyeing as well. Affect of ultrasonic dyeing on the morphology, chemical state, crystallographic structure and mechanical strength of PAN nanofibers has been studied. PAN nanofiber samples were characterized by SEM, FTIR, XRD and tensile strength tests. The results revealed 80 °C and 60 min as optimum temperature and time for ultrasonic dyeing of PAN nanofibers. The ultrasonic dyeing does not affect morphology, chemical and crystalline structure of the PAN nanofibers while it improves their mechanical strength. Our research suggests dyeability of PAN nanofibers with disperse dyes by ultrasonic method and their subsequent use in textile apparels.