The hydrophilic modification of acrylic textile fibers by grafting of 2-hydroxyethyl methacrylate and investigation of the imparted properties

In this study, to mimic the hydrophilic character of cotton, the industrially prominent polyacrylonitrile (PAN) fibers were enriched by polar OH-groups via the graft copolymerization technique. For this purpose, the grafting of the 2-hydroxyethyl methacrylate (HEMA) was ensured in the high graft yields (similar to 95%). The effects of polymerization conditions such as the solvent selection, initiator type and concentration, monomer concentration, polymerization temperature, and time were investigated for the highest graft yield, where the fiber's dimensional stability is preserved. The changes in the structural, thermal, and morphological properties of PAN-g-HEMA fibers were executed by ATR-FTIR, H-1-NMR, TGA, and SEM techniques. Depending on the modified fibers' grafting yields, the changes in the tensile strength, elongation at break, moisture, and water retention properties were investigated. It was obtained that the moisture absorption of PAN fiber (2%) reached 15.7% after grafting (95% graft yield). The dyeability of the modified fibers was studied with a direct dye (Direct Black 38), which is conventionally employed for cellulose dyeing, by monitoring with the L*a*b* color measurements and K/S color strength. 0.049 g of dye was adsorbed by 1 g of PAN-g-HEMA fiber containing 68% of HEMA at pH 11 for 120 min.