Desized and scoured cotton fabric is treated in a two-step process with sodium hydroxide/ liquid ammonia and liquid ammonia/sodium hydroxide to investigate the effect of the treatment sequence. Crystallinity, moisture regain, water absorbency, dyeability, and KES mechanical properties are measured. Despite a considerable decrease in crystallinity with both treatments, water absorbency decreases with NaOH/NH 3 and increases with NH 3 /NaOH compared with the untreated fabric. Furthermore, the NaOH/NH 3 treatment decreases the early dyeing rate with CI Direct Blue 1, whereas the NH 3 /NaOH treatment increases the rate remarkably compared to the untreated fabric. Nevertheless, saturation dye uptake with the same dye increases with both treatments compared with the untreated. As a measure of fabric hand, shearing and bending hysteresis curves are obtained with a KES instrument. The shearing modulus and shearing hysteresis width of the NaOH/NH 3 treated fabric are much smaller than those of the NH3 treated fabric, while those of the NH 3 /NaOH treated fabric are smaller compared with the NaOH treated fabric. From these results, it is clear that two-step processes such as NaOH/NH 3 and NH 3 /NaOH are much more effective for softening hand than the NH3 and NaOH treatments independently.Liquid ammonia treatment of cotton fabric is known to improve the softness of hand [I]. This treatment changes the crystallite structure from cellulose I to cellulose III. Water absorbency and dyeing properties with the treatment are almost unchanged, despite a considerable decrease in crystallinity [2][3][4][5][6][8][9][10][11].Although the decrease in crystallinity with the customary sodium hydroxide mercerization is smaller than that with the liquid ammonia treatment, dyeing properties increase considerably compared with the liquid ammonia, which greatly contributes to a soft hand [ 13]. Previously, we investigated the effect of liquid ammonia and sodium hydroxide/liquid ammonia treatments on mechanical properties with the KES instrument in relation to fabric hand [ 12]. It is clear that the sodium hydroxide/ liquid ammonia two-step process is much more effective at improving the softness of hand than liquid ammonia individually.In this paper, to obtain the highest hand softness and dyeing properties with a liquid ammonia treatment, we have treated cotton fabric with the following two-step processes-sodium hydroxide/liquid ammonia and liquid ammonia/sodium hydroxide. We have measured dye uptake with Cl Direct Blue 1 and mechanical properties with the t~s instrument, and we compare the effects of two-step processes with those of the sodium hydroxide and liquid ammonia treatments separately. ExperimentalDesized and scoured 40 thread count cotton fabric was mercerized with 20% sodium hydroxide (NaOH) solution for 1 minute at 20°C using a practical range and then treated with liquid ammonia (NH3) for 2 seconds at -33.4°C, also using a practical range to produce NaOH/ NH3 and NH3/NaOH treated cottons.The crystallinity of cotton fibers treate...
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