Abstract
The effect of moisture upon the rigidity of raw silk, viscose rayon and vinylon was examined, and the following results were obtained.
1) The rigidity of raw silk was gradually lowered according to the increase of relative humidity until the relative humidity reached about 65% RH, but above 70% RH it sharply lowered.
On the relation between the rigidity and the moisture regain, following results were obtained. The rigidity of raw silk was slowly lowered according to the increase of moisture regain from 6% to 10%, and above 11% of moisture regain the rigidity was sharply lowerd, but after that it was gradually lowered again. Vinylon showed the similar behaviour to raw silk. In the case of viscose rayon, however, the rigidity was almost linearly lowered according to the increase of moisture regain from 7% to 26%.
2) The relative rigidity of wet raw silk to dry raw silk was about 0. 2, and that of vinylon was about 0.45.
3) The rigidity of the raw silk from the outer layer of cocoon was more influenced by relative humidity than that from the inner layer.
