IMPROVING THE DYEABILITY OF WOOL BY TREATMENT WITH CHITOSAN

A study of pretreatment of wool fabrics with chitosan by a pad-dry met hod has been carried out. The pretreatment effectively eliminates diff erences in dyeing behaviour between damaged and undamaged wool fibres, with an increase in the rate of dye uptake and the exhaustion of acid and reactive dyes. Penetration of the fibre by dyes has been followed using fluorescence microscopy and the role of the chitosan coating in the dyeing process clarified. Similar colour fastness properties were obtained on both untreated and chitosan-treated wool fabrics. The chi tosan coating on wool fabrics has been examined by scanning electron m icroscopy. Evidence for the presence of chitosan was sought using a co lorimetric method. It is believed that an approximately uniform and ad herent chitosan sheath is formed on individual wool fibres.