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The reactivities of disulphide bonds in different compounds show considerable variation. For example, the rates of decomposition of simple cystine derivatives with alkali vary widely (Schoberl & Hornung, 1938) and oxidized glutathione (GSSG) reacts very much faster with silver nitrate than does cystine (Cecil, 1950). This paper describes kinetic studies of the reactions of some disulphides with sodium sulphite. Clarke (1932) and Lugg (1932) showed that the reaction is RSSR + Na2SO3 = RSNa + RSSO3Na.

The application of polymers to wool is considered from the point of view of the surface free energies of wool and the polymers. A theory is developed explaining the effectiveness of different polymers in reducing felting shrinkage as heing due to the ease with which spreading can occur over the surface of the wool fibers. It is shown that a useful criterion for spreading is that γ, (the critical surface tension) of wool must be greater than γe of the applied polymer. Spreading coefficients are calculated for various polymers on normal wool and on wool pretreated with chemical reagents. The spreading coefficients agree with the relatiye effects of chemical pretreatments, which can improve the efficiency of polymer treatments. The best pretreatments are those which increase the critical surface tension of wool from 45 dyne cm (normal wool) to 65-70 dyne cm.

Concentrated salt solutions protect wool from oxidative degradation. Oxidizing agents produce a higher degree of shrink resistance in concentrated salt solutions than in the absence of salt. Many oxidations, followed by a reduction, shrinkproof wool when either treatment alone does not.Results support the idea [20, 46] that attack on disulfide bonds is the only primary reaction during chemical shrinkproofing and that attack at some other point of the protein structure need not occur. However, breaking of disulfide bonds is not sufficient in itself to produce shrinkproofing effects, and the exact nature of chemical changes leading to shrinkproofing is unknown. No conclusive evidence has been found to decide whether or not changes in frictional properties are the general cause of shrinkproofing.Evidence is given that, under conditions where swelling is less than in simple aqueous solutions, reaction still occurs throughout wool fibers rather than only at the surface.The results do not agree with theories which suggest that shrinkproofing is due in some way to formation of degraded layers of protein material in wool fibers.

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