Structures and physical properties of polyvinyl alcohol/sericin blend hydrogel fibers

摘要

Blend-fiber of polyvinyl alcohol with silk sericin was prepared by a gel spinning method which was developed in our laboratory for both the application of sericin and the functional improvement of PVA fiber, and was investigated regarding the structures and physical properties of the fibers as formalized by the Sakurada Method after drawing and heating. It was difficult to make PVA fiber only by the gel spinning method. The crystallinity was approximately 40% and the crystal orientation was 90% for the highest drown fibers. The amorphous chains of PVA oriented less than ordinary Vinylon fiber. The undrown fiber elongated approximately 10% by swelling below 60 deg C. Elongation decreased with drawing because of the increase of the crystal orientation. The unformalized PVA amorphous chains began to dissolve slightly above 60 deg C and drastically above 90 deg C. Consequently the melting of samples above 90 deg C accompanied by the relative large contraction of the drown fibers, because of melting of PVA crystalline region. The values of breaking strength and elongation of the highest drown fiber were half that and twice that of Vinylon respectively. Although amorphous PVA chains could not be fully oriented, Young's moduli of samples were almost the same as Vinylon, because sericin had higher Young's modulus than PVA, and sericin molecules formed a molecular bundle with amorphous PVA chains.