Changes in Structure and Properties of Soybean Protein/Poly （vinyl alcohol） Blended Fibers Subjected to Wet Heat Treatment

The properties of soybean protein/poly（vinyl alcohol） （SP/ PVA） blended fibers subjected to wet heat treatment in hot water were measured. The structure of fibers was investigated by scanning electron microscope （SEM）, Fourier transform infrared （FTIR） spectroscopy, wide-angle X-ray diffraction （WXD） and differential scanning calorimetry （DSC）. The results show that the wet heat treatment above 100℃ has a great influence on the properties and structure of SP/PVA blended fibers. After the wet heat treatment at high temperature, the fibers exhibit the severe shrinking and yellowing, the great decrease in breaking strength and adhesive aggregation. The fibers show a broader main X-ray diffraction peak with the disappearance of minor diffraction peaks, a double DSC melting behavior with the peak temperatures of 215 and 233℃, and a weaker intensity of crystallization-sensitive absorbance peak of PVA component at 1 142 cm^-1. Therefore it is concluded that the wet heat treatment above 100℃ leads to a change in the crystalline structure of fibers and the scission and degradation of PVA macromolecular chains.

Changes in Structure and Properties of Soybean Protein/Poly (vinyl alcohol) Blended Fibers Subjected to Wet Heat Treatment

The properties of soybean protein/poly (vinyl alcohol) (SP/PVA) blended fibers subjected to wet heat treatment in hot water were measured. The structure of fibers was investigated by scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The results show that the wet heat treatment above 100℃ has a great influence on the properties and structure of SP/PVA blended fibers. After the wet heat treatment at high temperature, the fibers exhibit the severe shrinking and yellowing, the great decrease in breaking strength and adhesive aggregation. The fibers show a broader main X-ray diffraction peak with the disappearance of minor diffraction peaks, a double DSC melting behavior with the peak temperatures of 215 and 233℃, and a weaker intensity of crystallization-sensitive absorbance peak of PVA component at 1142 cm-1. Therefore it is concluded that the wet heat treatment above 100℃ leads to a change in the crystalline structure of fibers and the scission and degradation of PVA macromolecular chains.