抄録
In this paper, the observation of silk fibroin was performed in order to obtain the changes of their peculiar depression phenomena during the exposure to ultra-violet ray.
Silk fibroin of Bombyx mori wax exposed in textural form to ultra-violet ray for the different length of time in dry and wet states, and then the observation was made mainly about transition of the peculiar depression phenomena with the electron microscope and about variation of its physical properties.
Due to optically destructing action with ultra-violet ray, shallow linear or circular pepressions with partial cracks or partial strips were seen at the early stage of exposure, and with the increase of exposing time, depressed areas were seen expanded in both horizontal and vertical directions showing the destruction in the way of chain reacting and moreover showing the tendency of depressing and cutting the principal axis.
The phase of wet exposure was revealed more significantly and more severe than that of dry exposure.
Judging from the above result and variation of its physical properties, it can be conceived that those preculiar depression phenomena grow significant in proportion of the advance of the exposure and that those phenomena are due to weak-point of tyrosine area in silk fibroin.
