Studies of Urea‐assisted Wool Dyeing

Cut segments of wool, as well as whole fibres, have been immersed, under standard conditions, in concentrated aqueous urea. The diameter of each fibre or segment was then determined and compared with that of a control. No swelling occurred with whole fibres, but swelling was observed with the segments, the extent of swelling, in a given time, being inversely proportional to the length of the cut segment. The swelling of cut fibres increased with the time of immersion in concentrated aqueous urea. It is concluded that urea diffused into the cut ends of wool fibres, but that the epicuticle, if intact, is impervious to urea.