Low-temperature bleaching of knit fabric from regenerated bamboo fibers with different peracetic acid bleaching processes

Abstract

The bleaching of textile fibers with peracetic acid (PAA) results in adequate whiteness at low temperature and neutral pH media. PAA can be added to the bleaching bath in the form of a commercial solution or can be produced in situ in the presence of hydrogen peroxide (H2O2) with the addition of a bleach activator, tetraacetylethylenediamine (TAED), or arylesterase enzymes. In the present study, a knit fabric from regenerated bamboo fibers was bleached with four different PAA bleaching processes: with only PAA, with PAA or H2O2 in combination with TAED, and with H2O2 in combination with arylesterase enzymes. The knit fabric was also bleached conventionally with H2O2 for comparison purposes. Whereas the conventional H2O2 process was carried out at 90℃ and in highly alkaline pH media, the bleaching processes with PAA were carried out at 65℃ and in neutral to slightly alkaline pH media. The bleaching processes with PAA have a strong whitening ability that is comparable to that of the conventional bleaching process with H2O2. The highest whiteness index of the bamboo knit fabrics bleached by different processes was measured after the bleaching process with PAA in combination with TAED (WI 71.2). Overall, with PAA bleaching processes, bamboo knit fabrics with a high degree of whiteness, high water absorbency, and high tenacity can be obtained with low water and energy consumption.