Activated Peroxide for Enzymatic Control of Wool Shrinkage Part I: Elucidation

Abstract

The ARS process combines activated peroxide for pretreatment and enzyme for subsequent treatment to provide bleached, biopolished, and shrinkage-resistant wool. The pretreatment step is of particular interest because it combines dicyandiamide (DD) with alkaline peroxide to form peroxycarboximidic acid, a stable and powerful bleaching agent that is stabilized by gluconic acid (GA) when applied at pH 11.5 for 30 minutes at 30 ° C. Analytical methods of analysis provided information showing that the active bleaching component, peroxycarboximidic acid, is formed immediately upon the combination of DD with alkaline H2O2 and that cyanamide forms concomitantly as a co-product. The peroxide pretreatment bath was stable at room temperature for up to 4.5 hours with only 10% peroxide consumed. It should therefore be possible to reconstitute the bleaching bath for further utilization. The eventual alkaline hydrolysis of cyanamide to form urea and the recombination of urea with peroxycarboximidic acid formed the end-product, guanylurea, shown by high performance liquid chromatography associated with electron impact mass spectrometry (LC/EI-MS), Fourier transforminfrared (FT-IR), and 13C NMR. Differential scanning calorimetry and peroxide titration of pretreatment baths provided evidence that GA stabilizes the activated peroxide. Activated DD peroxide pretreatment is essential to the ARS process for it provides a high level of whiteness without loss in fabric properties and it prepares the wool fiber for enzymatic treatment designed to selectively modify the scales of wool to biopolish the fabric surface and provide itch-free, machine-washable wool.

Effect of ozone and ultrasound on the fiber properties of angora rabbit

“…Consequently, the ozone oxidized the cystine linkage present on the Angora fiber's surface to cysteic acid, and an improvement in the dyeability and chemical damage was observed. [32][33][34]41 This is in good agreement with the SEM photographs of the Angora fiber and correlates with the observed significant improvement in the dyeability and moisture conductivity.…”

Bioscouring of Wool Using Protease From Bacillus Subtilis Isolated From Abattoir Waste

“…al., 2012). Enzymatic treatment of textiles has been of great interest because of its effectiveness under mild treatment conditions (Cardamone et al, 2006). Enzymes act in the pH range between 5 and 8, at temperatures around 30 to 40ºC at atmospheric pressure while conventional method requires pH 10.8 at temperature around 60ºC -80ºC.…”

Biohydrolysis of nylon 6,6 fiber with different proteolytic enzymes

“…A great many studies have been carried out on the application of enzymes on natural fibers, including cotton surface modification to enhance the handling and appearance [5][6][7]; removing undesirable byproducts from the unscoured cotton [5]; desizing by enzymatic hydrolysis [3,5]; enzyme treatment of bleaching effluent [8,9]; softening woody fibers during retting [10,11]; shrink-proofing, softening, improving dyeability and pilling behavior of wool [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and silk degumming [30,31].…”