Dyeing of polyacrylonitrile nanofibers with CI Reactive Red 2 enabled by the introduction of polyethyleneimine

The color of textiles plays a crucial role in meeting humans' aesthetics needs and pleasure. Nanofiber has potential application prospects in textile and apparel due to its superior properties, such as the high specific surface area and porosity. Simultaneously, the coloring property has attracted widespread attention. However, the dyeing of polyacrylonitrile (PAN) nanofibers with reactive dyes remains a challenge due to the lack of reactive groups. Herein, an efficient strategy is proposed to successfully color electrospun PAN nanofibers with CI Reactive Red 2, enabled by introducing polyethyleneimine (PEI). Firstly, through entangling the molecular chain of PEI in solution, PAN is endowed with abundant cationic groups. Then, PAN/PEI nanofibers were obtained by electrospinning technology and further dyed using the reactive dye. More specifically, the different dyeing parameters, such as dyeing time, temperature, concentration and PEI concentration, were optimized. Compared to pure PAN nanofiber, PAN/PEI nanofiber achieved a higher dye uptake (96%) and better color fastness. This work offers an energy-saving and simple manner for improving the dyeing performance of PAN nanofibers using reactive dye.