86—THE ACTION OF HEAT ON WOOL

Publisher Website
Google Scholar
Abstract
Details are given for the rate of change in colour, weight, alkali-solubility, water-solubility, nitrogen, cystine and tyrosine contents and the work to stretch fibres 30% when wool fibres are heated in air at 200°C. In addition, the acid–base titration curve of wool heated for 30 min at 200°C is compared with that of untreated wool and figures are given for the adsorption of water at various relative humidities by wool which has been heated at 200°C for various times. As the depth of colour of the material increases, so does the alkali- and water-solubility, while the cystine content falls steadily and that of tyrosine only slightly. The resistance of the fibres to extension is also greatly reduced. The relationships between the changes in the various physical and chemical characteristics are discussed. A gradual fall in the cystine content to almost zero is the most marked chemical change. Attack on the amino groups in the wool is comparatively small, as the acid-combining power of the wool is hardly affected. The base-combining power is, however, increased. Wool modified by sulphonation, particularly by immersion for 15 sec in concentrated sulphuric acid followed by thorough rinsing, by treatment with aluminium sulphate or a mixture of borax and boric acid, or a mixture of THPC and urea, is less susceptible than untreated wool to yellowing when heated at 200°C.

This publication has 16 references indexed in Scilit: