Green alternative treatment for cellulosic fibers: ionic liquid modification of Abelmoschus esculentus fibers with methyl-tri-n-butyl ammonium methyl sulphate

Abstract

In this research, Okra (Abelmoschus esculentus) fibers were treated with an ionic liquid, methyl-tri-n-butyl ammonium methyl sulphate, to modify surface of the fibers. The fibers were exposed to aqueous ionic liquid solutions at different concentrations such as; 2, 5, 10 and 20 w/v% at ambient temperature. Ionic liquid treatment led to enhanced surface hydrophobicity of the okra fibers by means of increase in surface carbon/oxygen ratio. The proportion of C–C and C–H bands in the okra fibers were increased as a result of the treatment. The untreated and treated okra fibers gave similar crystalline index (CI) values. The CI results varied between 61.12 and 65.92%. Thermal stability of the fiber deteriorated after the treatment. However, char yield values increased indicating possibly enhanced flame retardancy after the treatments. Scanning electron microscopy observation confirmed the existence of ionic liquid both in intercellular gaps and on the surface of the okra fibers.