THE GLASS-TRANSITION OF WOOL - AN IMPROVED DETERMINATION USING DSC

The glass transition temperature (T-g) of wool and its dependence on w ater content is reinvestigated using differential scanning calorimetry (DSC). Previous studies with DSC have not accounted for the influence of thermal history, which may introduce a large variability in T-g me asurements. Because the T-g of wool is an important parameter affectin g textile performance and properties, it needs to be clearly defined. When the finite volume of the water-impenetrable phase is taken into a ccount, an important correction of the Fox equation is obtained, descr ibing the dependence of T-g on water content. On melting of the water- impenetrable crystalline regions, a reduction in the temperature range of the glass transition region is apparent, suggesting that the cryst alline regions behave in a manner analogous to filler particles in rub ber. The ratio of the change in heat capacity at the glass transition, before and after melting, may provide a way to estimate the crystalli ne weight fraction in native wool.