Abstract
The nature of the reaction of sulfuric acid with wool at 105° C. depends on the water content of the acid-wool system. When wool moistened with dilute sulfuric acid is heated in a closed system to prevent loss of the water present (approximately 40% of the dry weight of the wool), there is a slow decrease in tensile strength and a marked increase in alkali solubility and, after pretreatment with alkali or alkaline caprate at 30° C., in digestibility by trypsin. By contrast, when the acid-wool is dehydrated before heating there is a rapid decrease in tensile strength but little change in alkali solubility or trypsin digestibility. The addition of a surface active agent to the acid prevents loss of strength of the wool, particularly under anhydrous conditions, and it also reduces deterioration of color.
It is concluded that sulfuric acid can attack wool by at least two different reactions and that there is little direct relationship between alkali solubilit and fiber strength.
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