The Rôle of the Disulphide Bond in Reactions which render Wool Non‐felting

It is shown from experiments with peracetic acid that breakdown of the disulphide bond alone does not remove the d.f.e. of wool fibres and thus cannot bring about non‐felting by surface attack alone. Extensive disulphide bond breakdown without attack on other groups renders wool non‐felting by‐modification of the elastic properties of the fibres as a whole. It is concluded that, to remove the d.f.e. of a fibre and to render wool unshrinkable by attack on the surface only, two reactions are necessary— firstly, as recognized by Speakman4,5, splitting of the disulphide bond without formation of a new crosslink; and secondly, breakdown of the wool molecule at another point, which in the case of the well known anti‐shrink processes probably occurs at the tyrosine residue in the polypeptide chain.