Influence of the molecular mass of chitosan on shrink‐resistance and dyeing properties of chitosantreated wool

Wool fabrics were treated with the biopolymer chitosan under conditions which conferred shrinkresistance and dyeing improvement. In order to enhance chitosan absorption in wool, two different oxidative chemical pretreatments, hydrogen peroxide and permonosulphuric acid, were performed on wool fabrics prior to chitosan application. Chitosans of three different molecular masses, but with the same acetylation degrees of, were applied to unpretreated and oxidated wool and the influence of the molecular mass of chitosan and the oxidative pretreatment on shrink‐resistance and dyeing behaviour was assessed. In conclusion, both molecular mass and oxidative pretreatment exert an influence on shrink‐resistance. However, dyeing behaviour depends only on the presence of chitosan on wool fibre.