Preparation and adsorption properties of amphoteric viscose fiber

Among the regenerated cellulosic fibers, viscose fiber is the most harmless material on human skin. Nonetheless, viscose fiber has some disadvantages such as low wet strength, high elongation, flammability, and poor color fastness. To improve adsorption and color fastness properties of viscose fiber, amphoteric viscose fibers were prepared. In the current study, viscose fiber was modified with 2,3-epoxy propyltrimethyl ammonium chloride and sodium chloroacetate using sodium hydroxide as catalyst. With adsorption performance of methyl orange and methylene blue as target dyes, the modification conditions were optimized in terms of temperature, time, and catalyst dosage with orthogonal test and single-factor experiment. The modified product was characterized using Fourier transform infrared spectrometry, scanning electron microscopy, ultraviolet spectrophotometry. Meanwhile, nitrogen content, degree of substitution, tensile strength, and adsorption property were measured. It was concluded that the best cationic reaction process conditions were reaction temperature of 70 °C, reaction time of 1 h, and sodium hydroxide dosage of 0.09 g, which was 1% of the amount of viscose fiber when the amount of etherifying agent was 30% of viscose fiber. The best anionic reaction conditions were reaction temperature of 70 °C, reaction time of 1 h, and 3.3 g of 10% sodium hydroxide solution. The adsorption properties of amphoteric modified viscose fiber towards methylene blue and methyl orange were excellent. The maximum adsorption of methylene blue and methyl orange was obtained at 1.483 and 0.234 mg g−1, respectively.