Effects of Level of Fiber Opening on Moisture Regain, Tenacity, and Breakage of Wool

We have studied the effects of the level of fiber opening, expressed in points per fiber (ppf), on the reduction in moisture regain of wool, the fiber tenacity change, and the associated level of fiber breakage in an opening process. Two kinds of short Merino cardings wool are first converted into draw slivers, which are then opened at different opening levels on an open-end rotor spinner. The draw slivers are free from vegetable matter contamination in order to limit the number of variables in this study. The results indicate that as the ppf value increases, the reduction in fiber moisture regain increases linearly. The test of fiber bundle strength reveals that fiber tenacity drops after opening, but this drop is not proportional to the level of fiber opening. Reasons for this disproportion are discussed. Percent of fiber breakage during opening is examined by measuring changes in mean fiber length before and after opening; it also increases linearly with increasing ppf values.