Studies on the Shrink-Resist Treatment of Wool with Potassium Permanganate

Abstract

A detailed investigation of the shrink-resist effect imparted to wool by potassium permanganate solution is described. The KMnO4 consumed by the wool increased with time, temperature, and concentration of the treating bath. The addi tion of a relatively small amount of sodium chloride in the range of 10 g/l. to the KMnO4 treatment bath incrased to some extent the KMnO4 consumed by the wool. The acidic KMnO4 treatment imparted better shrink resist properties to the wool, as well as less yellowing when compared with an alkaline treatment. The treatment produced some bleach ing effects to wool that makes it possible to use milder bleaching conditions subsequently without effecting the level of whiteness. Amino acids cystine, tyrosine, and tryptophan were greatly affected by the KMnO4 treatment. This observation may be compared with the changes associated with chlorinated or H2O2 treated wool. Nitrogen and sulfur contents decreased with increased extent of KMnO4 treatment. Alkali and urea bisulfite solubilities of the treated wool increased and were favored by increase in pH, temperature, and concentration of the KMnO4 solution. Tensile strength and elongation of the treated wool were decreased slightly by the KMnO4 treatment. The affinity of treated wool to dyeing increased, and brighter colors were imparted to dyed wool in the case of pale and medium shades as compared to untreated wool. No change in the color of the treated wool after suitable KMnO4 treat ment was observed.

Effect of Corona and Oxidation Pretreatments on Grafting in Wool Fabric

“…The samples were subjected to BS methods 2576/1959 and 3556/ 1961 for tensile strength, percentage elongation at break, and bending length. [5] made similar observations. The stiffness (bending length of fabric may be considered proportional to fabric stiffness) of fabric B is comparable to fabric A.…”

“…The tensile strength of corona treated fabric C is decreased by about 8% and stiffness is slightly increased. It appears that mild oxidation produces only a small number of free radicals [5], if any, and therefore properties of fabric B are comparable to fabric A. The decreased tensile strength in fabric C, however, may be due to simultaneous wool fiber degradation and creation of free radicals.…”

The Impact of Nitrogen Plasma Treatment upon the Physical-Chemical and Dyeing Properties of Wool Fabric

“…The outer surface, the cuticle cells, are hydrophobic in nature due to the presence of proteins with a high cystine-disulfide content along with the covalently bound fatty acid, monolayer on the fiber surface, thereby acting as a surface barrier against diffusion and penetration of dyestuffs and finishing agents into the wool-structure [3,4] . Much attention is being focused on replacement of traditional chemical treatments [3,[5][6][7][8] with more environmentally friendly processes [1,4,[9][10][11][12][13][14] i.e., with low-or zero-effluent processes, to upgrade the quality and to enhance the performance properties of wool fabrics.…”

An ethoxylated alkyl phosphate (anionic surfactant) for the promotion of activities of proteases and its potential use in the enzymatic processing of wool

“…These impurities need to be removed in order to obtain a hydrophilic fibre that can interact with other chemicals. Various methods have been studied by researchers for this purpose including: alkaline scouring using sodium carbonate (Halliday 2002); pretreatment using sodium sulphite as a reducing agent (Erra et al 1987); pretreatment using hydrogen peroxide (Gacen et al 2000) or potassium permanganate (Kantouch et al 1978) as an oxidising agent; the addition of a particular surfactant (Julia et al 1985); and pretreatment using protease (Heine et al 1995, Nolte et al 1996. In the enzymatic treatment of wool, non-ionic surfactants are widely recommended to be used due to their compatibility with proteases.…”