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We attempted to use the keratin resin as a crystallizable adhesive agent serving as the binder for the milled wood fillers to develop a totally bio-based wood filler-feather keratin resin composite (WKC). The milled feathers could be resinified easily via the hot-press compression molding. WAXD measurements revealed that the four-fold screw structure of the feather keratin crystal could be easily destroyed by mechanically milling. However, it was also revealed that the limited molecular rearrangement in the stacking direction of the β-sheets occurred during the hot-press compression molding. Compared with the hot-press compression molding, the sintering method was more effective not only to resinify the milled feathers but also to induce the recrystallization of feather keratin in both longitudinal and lateral directions. The WKC comprised of a feather resin matrix produced using the finely milled feathers exhibited superior mechanical properties. Unevenly milled feathers seemed to conduct heterogeneous resinification. As a result, the adhesion at the interface between the wood filler and feather resin became weaker. The newly developed WKC could retain the bending properties comparable to those of a virgin one even after the successive milling-remolding procedure for three times. [ABSTRACT FROM AUTHOR]

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We attempted to produce three dimensional (3D) aero-sponges using liquid silk (LS) extracted from the silk glands of fully grown larvae of Bombyx mori silkworms by combining an ice-crystal-sublimation method and a water-annealing treatment. The pore structure of the 3D LS-aero-sponge was constructed by the branched fibrous substrates and the films with small holes. It was assumed that the branched fibrous structure was mainly comprised of fibroin whereas the films were comprised of the fibroin interacting with the sericin fractions. Most of the WAXD peaks from the as-molded 3D LS-aero-sponge could be assigned to the silk1 crystal diffraction peaks of fibroin. The silk1 crystal modification of fibroin formed in the course of the production of the 3D LS-aero-sponge could bring about a good thermal shrinkproof property. Furthermore, a gamma ray irradiation treatment applied prior to the cell proliferation tests of the 3D LS-aero-sponges was found to be effective to form cross-linking in the sericin fractions. As a result, the yield stress in the compression tests of the 3D LS-aero-sponges was increased. The 3D LS-aero-sponge exhibited a good living cell proliferation properly in the culture tests using NH3T3 cells (Swiss albino mice embryonic fibroblasts) although that of the 2D LS-cast films was very poor. We suggest the good cell proliferation property of the 3D LS-aero-sponge was due to the continuous branched fibrous structure comprised of fibroin. [ABSTRACT FROM AUTHOR]

Herein, the anesthetization of Bombyx mori silkworms via the water narcosis treatment by soaking in room-temperature water for 1 h was found effective in keeping the tensile strength of its forcibly spun silk filament comparable to that of naturally spun silks. However, at a treatment time of 3 h, a marked decrease in the tensile strength of the forcibly spun filaments was observed owing to the interference of the applied force in the forcibly spinning with the inherent naturally spinning system of Bombyx mori silkworms. Compared with naturally spun cocoon filaments, evidence of disordering in the crystal modification of silk fibroin by the forcibly spinning suggests that variations to the forcibly spinning conditions may affect the quality of the silkworm fibers. [ABSTRACT FROM AUTHOR]

The self-assembling behavior of Bombyx mori silkworm fibroin was investigated focusing on the interaction of the two types of silkworm sericin fractions (P, M) with the fibroin in the static and flow states. The dissociation of the sericin M fraction from the fibroin allowed the fibroin to form the silk2 crystal guided by the sericin P fraction still interacting with the fibroin. Water annealing in room temperature water, or the enzymatic hydrolysis caused by the contamination by fibroinase, weakened the interaction between the fibroin and the sericin M fraction. Thus, the interaction of the sericin P fraction with the fibroin was considered to be more stable than that of the sericin M fraction. As a result all of the entities that assembled in the flow state gave almost similar WAXD intensity curves although the coagulation conditions were changed at every trial. The morphology of the entities obtained in the flow state became film-like when a two-dimensional interface was generated between the fibroin and the free sericin molecules. On the other hand, it became fibrous when the fibroin interacted with a new protein fraction (a minor protein fraction that can cause the solution of fibroin into water) instead of the sericin fractions. [ABSTRACT FROM AUTHOR]

Various types of conjugate fibers comprised of polylactide (PLA) and polyethylene terephthalate (PET), with their blend in the sheath, PET as the core, were produced by high-speed melt-spinning. Due to the higher glass transition temperature of PET, the orientation-induced crystallization only occurred in the PET core. The crystalline and continuous PET core of the conjugate fibers effectively suppressed the shrinkage during dyeing, even in a pressurized water bath at 130 °C comparable to the commercial level, to less than 5% while achieving a color strength higher than 15. Post-annealing in the restrained mode could effectively cause the fine PET fibrils embedded in the sheath to rise out from the surface of the fibers during dyeing by the sliding friction force between the fibers. The PET fibrils rising out from the sheath were strong enough and showed an entangling behavior which would be useful to fabricate non-woven fabrics. The amorphous PLA domains exposed on the fiber surface showed the bacteriostatic activity valuable for the inhibition of the formation of biofilms. [ABSTRACT FROM AUTHOR]