As part of a program directed at zero-AOX shrinkproofing treatments, we have compared the reactivity of different oxidants with wool by following their disappearance under similar conditions. The reactivity series was as follows: aqueous chlorine > DCCA ~ permonosulfate > permanganate / salt > peracetic acid > permanganate > persulfate ~ hydrogen peroxide. This series was not related to redox potentials but generally followed the level of shrink resistance imparted by the oxidant. Fourier transform infrared spectroscopy using the attenuated total reflectance technique showed significant differences in the amounts of cystine oxidation products formed in the oxidations above. One new finding was the direct formation of low concentrations of Bunte salts by the oxidation of wool with persulfate. We further studied the surface of permonosulfate-treated fibers with scanning electron microscopy and frictional measurements. Permonosulfate treated wool fibers produce Allwörden sacs with chlo rine water, whereas aqueous chlorinated fibers do not. We suggest that the most likely mechanism for shrink resistance in permonosulfate treatments is the removal of de graded protein from below the exocuticle, producing a modified surface with a reduced differential friction between the "for" and "against" scale directions.

The absorption of mercuric ions by wool is strongly inhibited by sodium chloride. Complex metal ammines are readily sorbed from ammonia solutions and then desorbed from wool by acid. A technique suitable for removing low concentrations of copper from nickel solutions is described.

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SynopsisA series of prepolymers containing terminal blocked isocyanate groups was prepared by reaction of isocyanate-terminated prepolymers [derived from a poly(propy1ene oxide) diol (MW = 2000) or a triol (MW = 3000) and different diisocyanates] with various blocking agents. Their curing rates with a polyepoxide crosslinking agent were measured to assess their suitability for a delayed-cure durable-press treatment for wool. The curing rates varied over a wide range, but commonly used hlocking groups such as phenols, caprolactam, p-diketones, and alcohols were not sufficiently reactive for the intended application, although others, e.g., oximes and certain blocking agents containing a basic center such as N,N-diethylhydroxylamine, hydroxypyridines, and hydroxyquinolines, had the required reactivity. Blocking by 1,3-dipolar cycloaddition of nitrones was examined, but the reactivities were too low. Prepolymers containing blocked aromatic isocyanates were more reactive than those containing blocked aliphatic isocyanates. Difunctional butanone oxime-blocked prepolymers cured slightly more slowly than analogous trifunctional prepolymers.

A simple method has been devised to analyze a common type of nonionic surfactant (nonylphenol ethoxylate with an average of 8-15 ethylene oxide units) on wool. The advantages of this method are its insensitivity to the presence of processing oils and wool grease and its ability to detect concentrations as low as 0.02% on wool. The method involves isocratic, high-pressure liquid chromatography on a diol-bonded silica column. The amount of surface surfactant is determined