An eco-friendly strategy for grafting keratin onto polyacrylonitrile fabrics using bi-functional amino acids as coupling agents

Although it is widely used in the textile and apparel fields, polyacrylonitrile (PAN) fabrics have a hydrophobic surface susceptible to the creation of electrostatic charges (ESC). Herein, an eco-friendly method for improving some properties of PAN fabrics is proposed. PAN fabrics were hydrolyzed by a caustic soda solution to create carboxylic groups along their macromolecular chains. The hydrolyzed fabrics were treated with the amino acid lysine or glutamic acid, followed by the proteinic biopolymer keratin, using either the exhaustion or pad-dry-cure method. The used keratin was extracted from waste coarse wool fleece and characterized using amino acid analysis and SDG-PAGE electrophoresis. The effect of keratin concentration, reaction temperature, and duration on the weight gain of the treated fabrics was used to assign the optimum treatment conditions. The treated PAN fabric exhibited excellent wettability, antistatic properties, and improved resistance to UV rays without having a negative effect on the fabric's strength. The mechanism of the reaction between PAN fabric and the aforementioned reagents was proposed and supported by both C-13-NMR and FTIR spectroscopy. The effects of the applied reagent on some of the inherent properties of PAN fabrics were examined. The finished fabrics were durable to repeated washings up to 20 cycles, as indicated by the fabric's wettability and resistance to UV rays. Scanning electron microscopy was used to confirm the coating of the treated PAN fabrics with a layer of keratin.