Search

The precise identification of bast fibers such as ramie and hemp found at several archaeological sites is a very difficult problem because organic materials are usually heavily degraded during the long term preservation at underground or mound. Both excavated ramie and hemp usually show very similar degraded FT-IR spectra (glober light source). The authors are continuing to study the identification of several kinds of archaeological silk and vast fibers using BL43IR beam line (FT-IR micro-spectroscopy) at SPring-8. It has already known that excavated ramie and hemp show the possibility of distinguish ramie from hemp under polarized light source. In this report, various modern ramie fibers are analyzed by detailed IR polarization measurement. As a result of the measurement, the absorption band of 1160 cm-1 disappeared at 45° (angle of polarizer) irrespective of sample history. In the next measurement, the disappearance angle of specific peak of modern hemp (several origins) will be confirmed. The determination of specific disappearance of certain peak for ramie or hemp will be effective for the identification of each fiber. [ABSTRACT FROM AUTHOR]

The almost degraded silk fibers show deformed infrared spectra compared with that of reference silk fibers. In this report, the polarized micro infrared spectroscopy was used to clarify the reason for the deformation of spectrum. Since the polarized light is sensitive to the change in the secondary structure of fibroin molecules, the change in the crystallinity and the peak intensity ratio of spectrum of degraded silk fibers were evaluated. At first, the axis of single silk fiber was set parallel to the polarized light of 90°, and the spectra was measured successively by changing the angle of diamond cell until the final position of 0°, namely perpendicular to the axis of single silk fiber. As a result of the experiments, it was found that the crystallinity increases with progress in degradation. Furthermore, the crystallinity is higher in the direction for 90° compared with that for 0°. Furthermore, the peak intensity ratio, Amide I / Amide II, was adopted as the measure of degradation. The measured value was generally higher compared with that of reference silk fibers. The correlation between the crystallinity and Amide I / Amide II ratio was also investigated. [ABSTRACT FROM AUTHOR]

Excavated organic materials such as textile fabrics are usually heavily degraded and hence their scientific identification is rather difficult. The authors are continuing the analysis of degraded natural textile fibers using FT-IR microscopy to clarify their general characteristics at molecular level. In this report, the infrared spectra of silk fibers found at the Fujinoki tumulus were analyzed in detail. The most remarkable change of spectral patterns in degraded silk fibers compared with those of modern silk fibers was the broad superposed appearance of amide I and II absorption peaks. As a result of the investigation of the secondary structure of fibroin molecules, the main reason for the spectral deformation was found to be the increase in crystallinity associated with degradations. In this research, the FT-IR microscope at JASRI was used. It requires only very minute samples due to the bright IR light source using synchrotron radiation. This makes it convenient for the study of cultural properties. The identification of silk fibers in degraded state undoubtedly contributes to the understanding of historical features of the remains at a particular tumulus. [ABSTRACT FROM AUTHOR]

The silk fibroin/nylon 66 blended nanofiber webs were made by the electrospinning process and investigate the effect of blend ratio on the structure and surface properties of electrospun nanofiber assemblies. Tg of silk fibroin and nylon 66 blends in DSC curves shifted to that of nylon when the nylon content increased. With the increase of silk blend ratio, the decrease of the fiber diameter was observed. The mean coefficient of friction (MIU) was measured by KES surface tester. The obvious effect of fiber diameter on MIU was not found in the fiber diameter range of 50 to 270nm. Maximum values of MIU were observed for the silk/nylon blend ratio of 50/50%. [ABSTRACT FROM AUTHOR]