Surface modification of poly (ethylene terephthalate) using imidazolium-based ionic liquids

Abstract

Ionic liquids (ILs), with their unique characteristics, are widely known as new alternatives for solvents and catalysts used in various chemical reactions. Due to their extensive range of applications and environmental compatibility, they are suitable options for treating fibrous substrates. In this regard, this paper focuses on investigating the possibility of poly (ethylene terephthalate) surface modification via imidazolium-based ILs. Surface modification was carried out under different process conditions by varying the temperature and the catalyst. The possibility of treating samples in the IL solution for the second time was also examined. Moreover, the effect of the modification on the dyeing of polyester with disperse dye without carrier at 100 °C was studied. The samples’ wettability properties were investigated through several test methods by measuring vertical wicking height, wetting time, drop contact angle, surface resistivity and absorption of methylene blue dye. The chemical and physical changes of the modified samples were also evaluated via scanning electron microscopy images, Fourier-transform infrared spectroscopy (FTIR) spectra and mechanical tests. Results demonstrate that treatment with [BMIM]Cl and [BMIM]Br induces morphological changes on the fibre surface, creating grooves and voids. FTIR analysis and Methylene blue staining test confirm the formation of hydroxyl and carboxyl groups, enhancing the fabric's hydrophilicity and dyeability. Wettability tests reveal that increased water absorption leads to reduced electrical resistivity. Mechanical tests indicate a slight reduction in tensile strength attributed to surface roughness.