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...

Wool and poly ( ethylene terephthalate) fabrics and film were treated with low-tem perature plasmas of helium/argon or acetone/argon under atmospheric pressure for 10 to 180 seconds. Although argon itself cannot independently generate a plasma under atmospheric pressure by applying high frequency voltage, it is easily generated by adding a small quantity of helium or acetone to argon gas. Wettability of the fabrics and surface tension of the film increased considerably with the treatment within 30 seconds. ESCA analysis was used to elucidate the surface chemical composition of fibers treated with atmospheric low-temperature plasma. Relative O1 s intensity in creased considerably and oxygen was incorporated in the form of —CO— and —COO— on the fiber surface. From these results, it appears that low-temperature plasma by atmospheric pressure discharge is effective for modifying the polymer surface, as it acts in the same fashion as low-temperature plasma by glow discharge.

ABSTRACT:In a previous article, we reported on the ozone-gas treatment of wool and silk fabrics in relation to the gas-phase processing of textile fabrics. The treatment incorporated an oxygen element into the fiber surface and contributed to an increase in water penetration into the fabric. In this study, nylon 6 and polyester fabrics were treated with ozone gas in the same way as that of the wool and silk fabrics. The treatment incorporated much more oxygen into the fiber surface in the form of OCOH and OCOOH, as shown by electron spectroscopy for chemical analysis. Water penetration increased considerably with treatment, and the apparent dyeing rate and equilibrium dye uptake were also improved, especially for the polyester fabric, despite an increase in the crystallinity. Therefore, it seemed that the treatment brought about a change not only in the fiber surface but also in the internal structure of the fibers (the crystalline and amorphous regions) with regard to the dyeing behavior. Further, the mechanical characteristics of the ozone-gas-treated polyester and nylon 6 fabrics were measured with a Kawabata evaluation system apparatus. The shearing modulus and hysteresis widths increased with treatment, especially for the polyester fabric. Therefore, it was clear that the treatment caused a change in the fabric hand to crisp.

In a previous article, we reported that oxygen low temperature plasma treatment of wool fibers increases both the dyeing rate and saturation dye exhaustion of acid dyes, despite increased electronegativity of the fiber surface with the treatment. In this article, wool and nylon 6 fabrics treated with oxygen, carbon tetrafluoride, and ammonia low temperature plasmas are dyed with several natural dyes, such as cochineal, Chinese cork tree, madder, and gromwell. The dyeing rate of the plasma-treated wool increases con siderably with cochineal, Chinese cork tree, and madder, but not with gromwell. How ever, the dyeing rate of nylon 6 with cochineal and Chinese cork tree is not changed by the plasma pretreatment. Furthermore, plasma-treated wool fabrics dyed with cochineal and Chinese cork tree have increased brightness compared with untreated wool.

Merino wool top was treated with low-temperature plasmas of helium/ argon and acetone/argon under atmospheric pressure for 30 seconds and then dyed with two leveling-type acid dyes, CI acid orange 7 and CI acid red 18, and two milling-type acid dyes, CI acid blue 113 and CI acid blue 83. Dyeing rate and saturation dye exhaustion increased with the atmospheric low-temperature plasma treatments as with the dyeing of wools pretreated with low-temperature plasma by glow discharge of O2 and CF4. In particular, helium/ argon plasma was much more effective than acetone / argon plasma at improving dyeing properties, except for CI acid blue 113.

Wool and nylon 6 fibres treated with oxygen low‐temperature plasma were dyed with acid and basic dyes. Despite the increase of electronegativity of the fibre surface caused by the plasma treatment, the rate of dyeing of wool was increased with both dyes, while that of nylon 6 was decreased with the acid dye and increased with the basic dye.

Fibrillation-controlled lyocell fibers were developed by crosslinking reactions between dialdehyde cellulose (DAC) and multifunctional amines. DAC lyocell fibers were manufactured by partial oxidation with sodium metaperiodate and were successfully crosslinked with two multifunctional amines by Schiff-base formation. The amorphous regions and the char formations, which were characterized by differential scanning calorimetry and thermogravimetric analysis, increased with the degree of oxidation. After the crosslinking reactions, an increase in the amorphous regions also appeared, whereas the thermal stability was somewhat improved by the chain crosslinking. These results were in good agreement with viscosity-average degree of polymerization values in that they diminished with oxidation level and increased with the crosslinking reactions. The water retention value and moisture regain value decreased with the oxidation and crosslinking levels, which implied that the swellability of fibers and the water absorbency in characteristic sites decreased with them. The increase in the dry crease recovery angle also confirmed the presence of hemiacetal crosslinks in the DAC and amine crosslinks between the DAC and the amines. The fibrillation grade of the crosslinked fibers diminished with oxidation level and the amine concentration. In particular, the fibrillation properties of the crosslinked fibers with 4-hydroxy-2,4,6-triaminopyrimidine sulfate salt were more easily controlled than those of the crosslinked fibers with 2,4,6-triamino-1,3,5-triazine.

Both scoured and sodium hydroxide mercerised cotton fibres have been treated with liquid ammonia atndash33.4°C using commercial operating equipment and then the ammonia removed at 130°C in a hot drum. The moisture regain and water absorbency of the fibres treated with liquid ammonia were increased compared with values on untreated fibres, whereas both these parameters on mercerised cotton fibres were decreased by subsequent liquid ammonia treatment. The fibres were dyed with CI Direct Red 2 and CI Direct Blue 1. Liquid ammonia treatment of the scoured cotton fibres increased the rate of dyeing, equilibrium dye adsorption, standard affinity, heat of dyeing and change of entropy, while the dyeing properties of mercerised cotton were adversely affected by subsequent liquid ammonia treatment.