Physical properties of wool fibers modified with isocyanate compouds

Wool fibers were chemically modified with various kinds of isocyanates and diisocyanates. The reactivity of these modifying agents was examined as a function of the reaction solvent, temperature, time and isocyanate chemistry. The higher weight gains were obtained using dimethyl sulfoxide as the solvent, aliphatic mono and bifunctional isocyanates at a temperature of 75°C. The moisture content of wool fibers tended to decrease with increasing the weight gain, the extent of which depended on the isocyanate used. Monofunctional isocyanate caused a sharp drop of tensile strenght and an increase of elongation at break, while bifunctional isocyanate preserved the intrinsic tensile properties of wool. The wool FTIR spectra showed changes attributable to the incorporation of the modifying agents. DSC measurements showed remarkable changes in the thermal behaviour af acylated wool fibers.