Raw Silk Fiber Research Articles

Dyeing of Degummed Silk Fibers with Anthocyanins in Red Cabbage

Extraction of anthocyanins in red cabbage leaves was taken up using hydrochloric acid solution. Raw silk fibers were degummed with traditional Marseille soap. Then the dyeing of degummed silk fibers with anthocyanins extracted from red cabbage was investigated. It was concluded that, K/S of silk increased in the order of the dyeing with Co(II) > Zn(II) > Ni(II) > Fe(II) > Al(III). The maximum adsorption wavelength of dyed samples at different pH values shifted to different values and the color strength values also changed. In addition, the higher dye concentration, the higher color strength values. Deep shade (K/S value = 6.655) was achieved at 40°C and pH 2 using zinc chloride.

Production of Silk Sericin Nanofibers

Electrospinning is a scientifically attractive spinning technique, since it can produce fibers with the diameters ranging from the sub-micron to nano dimensional scale. The fiber diameters and their standard deviation primarily depend on the polymer solution properties and electrospinning process variables. Silk sericin powder was obtained from the raw silk fiber of Bombyx mori silkworm. The solution was prepared by dissolving silk sericin powder in water at 85 °C for 30 minutes. In the electrospinning process, voltage 20 kV was applied and the inner diameter of the syringe needle was 0.3 mm. The distance from the syringe tip to the target was 15 cm. The sericin nanofibers with smooth surfaces can not be produced at 40 wt%. However, fine nanofibers were produced at the concentrations of 50 wt% and 60 wt%. It was suggested that the average diameters of the nanofibers increased with increasing solution concentration and the optimum concentration was 50 wt% for best nanofibers. Then solution 50 wt% was electrospun with different voltages from 13 kV to 25 kV, the working distance is 10 cm, the as-spun silk nanofibers were produced and exhibited fine nanofibers with smooth surfaces. The average diameters and diameter distributions of the nanofibers decreased with increasing voltage.

Development of conservation procedures for late Edo period Japanese ceremonial dolls’ hair: Evaluation of effective treating reagents by using artificially degraded black-dyed silk fibres

Abstract Several procedures for conservation treatment were comparatively studied for degraded “ Suga- fibres” made of raw silk fibres dyed black. Two traditional methods, (1) neutralization with magnesium bicarbonate, and (2) antioxidant treatment with phytic acid, originally used for paper preservation, were tried for the conservation of Suga -fibres. The influences of a single treatment, or a combination of neutralization and antioxidant treatments, for the model fibres on their tensile strength were investigated under conditions of high humidity at high temperature before and after the accelerated aging test. The effect of the novel antioxidant cysteine on the fibre degradation was also examined. For the single treatments, the neutralization with magnesium bicarbonate retarded the degradation of higher iron-content iron (20%)/tannate-silk fibre, while the antioxidant with phytic acid treatment most effectively prevented the degradation of lower iron-content iron (2%)/tannate-silk fibre. This may be due to the different acidity in iron/tannate-silk fibres, and thus the degradation of iron (2%)/tannate-silk fibre would be caused by iron-catalyzed oxidation rather than acid-catalyzed hydrolysis because of its lower acidity. Among antioxidant treatments, cysteine more effectively retarded the degradation of the iron (20%)/tannate-silk fibre, while in the case of the iron (2%)/tannate-silk fibre, phytic acid more effectively conserved its strength and breaking strain. The result suggests that the thiol group of cysteine coordinates with an excess of ferrous ions in the iron (20%)/tannate-silk fibre and quenches the production of hydrogen peroxide. This study demonstrated that phytic acid, cysteine and magnesium bicarbonate treatments are useful as effective reagents for the conservation treatment of black-dyed textiles.

Studies on the properties of heat treated raw silk and silk fiber

Studies on the properties of heat treated raw silk and silk fiber

Changes of the hue on raw silk fibers of Antheraea yamamai by the irradiation of ultraviolet rays and the heat treatment

Changes of the hue on raw silk fibers of Antheraea yamamai by the irradiation of ultraviolet rays and the heat treatment

Consolidation Treatment of Japanese Ceremonial Doll's Hair at Edo Period with Polyethylene Glycol

The application of the polyethylene glycol (PEG) for consolidation treatment of Suga-fibers, made of raw silk fibers dyed in black, was investigated. The PEG treatment in the range of the concentration 5 wt % to 20 wt% using PEG#1000 and PEG#6000 was found to reinforce the deteriorated iron-silk fiber. The result may indicate that coating of PEG on the fiber surface acted as an antioxidant, and the production of H2O2 and OH• might be inhibited. For iron/tannate-silk fibers, the coating with 20 wt% PEG#6000 was the best pre-treatment, while that with 5 wt% PEG#1000 was suitable post-treatment to control the fiber deterioration by accelerated aging. This concluded that the osmotic and flexible PEG is effective for the fragile fiber. Depending on the degradation condition of Suga-fibers, it was important to select the appropriate molecular weight and concentration of PEG solution to reinforce. This study demonstrated that the PEG treatment is useful as one of the conservation treatment of black dyed textiles.

멜라민과 포르말린 혼합액의 첨 가제들이 실크 생사의 세리신 정착에 미치는 영향

실크 생사의 세리신 정착을 보다 효과적으로 하기위해 멜라민과 포르말린의 혼합액에 각종 첨가제를 첨가했을 때 첨가제가 세리신 정착에 미치는 영향을 살펴보았다. 멜라민과 포르말린의 혼합액으로 세리신을 정착할 때 수분침투 기능이 있는 계면활성제로 전처리라고 수세하지 않은 경우 견고한 정착이 이루어졌고, 정착액에 과산화수소를 첨가한 경우 정착 효과가 크게 떨어지면서 단사 간에 접착하는 문제가 발생했고, 하이드로를 첨가하여 <TEX>$60^{\circ}C$</TEX>에서 정착하는 경우에는 표백과 동시에 세리신 정착이 가능함을 확인했다. 낮은 농도의 수산화나트륨을 첨가한 알칼리 조건에서 멜라민을 추가함으로써 매우 견고한 세리신 정착 결과를 얻었으나 염산과 메탄을 추가는 정착에 그다지 효과적이지 못했고, 염화마그네슘 추가는 오히려 세리신 정착 견고성을 크게 저하시켰다. In order to investigate the effective sericin fixation of raw silk fibers the influence of various additives added to the melamine and formalin mixtures on sericin fixation was studied. When raw silk fibers were treated with wetting agent but without subsequent washing before sericin fixation, the strong sericin fixation was obtained by fixing sericin. Adding hydrogen peroxide to the melamine and formalin mixture made sericin fixation worse, resulting weaken the sericin hardness of fixed raw silk fibers and tight bonding of the fibers. On the other hand, it was confirmed that adding sodium hydrosulfite to the melamine and formalin mixtures gave better sericin hardness of fixed raw silk fibers without the bonding of fibers. Supplying additional melamine with he low concentration of sodium hydroxide to the melamine and formalin mixture(melamine:formalin= 1:6) resulted in very good sericin fixation. But adding hydrochloric acid or methanol to the same mixture had no effect on the sericin fixation, and adding magnesium chloride to it made the hardness of sericin fixation even worse.

아민류와 포르말린 혼합액에 의한 실크 생사의 세리신 정착에 관한 연구

To investigate the strong and effective sericin fixing agents and conditions, raw silk fibers were treated with the mixtures of urea-formalin, thiourea-formalin and melamine-formalin as sericin fixing agents, respectively. And the treated raw silk fibers were degummed by the degumming liquors of alkaline detergent and sodium carbonate to confirm the hardness of sericin fixation. The weight of raw silk fibers was decreased in the process of sericin fixation treating at 80 for 60min. The effective sericin fixation was obtained by treating at for 15min with the mixture of melamine and formalin. The mixture of melamine and formalin showed an outstanding ability of sericin fixation because the three amino groups of melamine were able to cross-link the hydroxy amino acids of sericin such as serine with the assistance of formalin.

Application of Low-Pressure Plasma Pretreatment in Silk Fabric Degumming Process

A novel and effective method was developed for raw silk fabric degumming with the application of low-pressure argon plasma in pretreatment combining a subsequent one-step mild wet-chemical process. The plasma parameters, such as argon pressure, discharge power and exposure time, were optimized according to degumming loss and the properties of fabric such as capillary rise, tensile strength, bending rigidity, etc. An optimized plasma pretreatment for raw silk fabric degumming was at 80 Pa of argon gas and 60 W glow discharge power for 5–10 min. The raw silk fabric and fibers pretreated by argon plasma were characterized by scanning electronic microscopy and X-ray powder diffraction. In comparison with a conventional degumming process, the proposed method achieved comparable degumming efficiency and properties of silk fabric, and it was more environmentally friendly by shortening the conventional wet-chemical treatment process, saving the dosage of degumming agents, water and energy.

Evaluation and Control Principle of the Crepe Effect on Fabrics

Fabrics made up of both raw silk and other fibers can form a kind of peculiar visual texture, which is know as the crepe effect, on fabric surfaces. However, the level of crepe is difficult to control. We put forward a method using image analysis and fractal geometry to evaluate the visual effect of creping, and analyze the relationships between the bending shape of yarns and the visual effect of creped fabrics. The results indicate that it is possible to control the crepe level by adjusting the fabric breadth during the breadth drawing process.

Composite cement of magnesium-bearing phosphoaluminate–hydroxyapatite reinforced by treated raw silk fiber

Abstract Hydraulic hardened paste of magnesium-bearing phosphoaluminate–hydroxyapatite composite cement (MPAHC) reinforced by 0.5 wt.% addition of raw silk possesses splitting strength of 14.9 ± 0.2 MPa and Vickers micro-hardness of 2.22 GPa, which are increased by 22.2% and 42.3%, respectively, in comparison with that of the control ones after curing for 24 h at 37 °C. X-ray linear scanning analysis and FT-IR spectra suggest that the chemical bonds might have been developed at the interface between the treated raw silk and the hydrates in MPAHC hardened pastes.

Structure - Property and Structure - Function Relations of Leafhopper (Kahaono montana) Silk

Kahaono montana Evans (Insecta: Hemiptera: Cicadellidae), an endemic Australian leafhopper, is unique among the insect order Hemiptera in producing a silk. In this study, the secondary structure of the protein comprising leafhopper silk, and the surface stretching mechanical properties of this biopolymer, were investigated using Fourier-transform infrared microscopy and atomic force microscopy, respectively. The curve-fitted amide I and amide III bands revealed a composition of 13.1% α-helix, 23.8% β-sheet, 25.5% random coil, and 37.6% aggregated side chains. The molecular stretching behaviour of raw and cleaned silk fibres differed markedly. Analysis of the AFM force curves showed an adhesive property of the raw silk, while the pure fibre showed only the presence of protein. These findings suggest that the silk fibres act as a structural support for other leafhopper secretions and together form a hydrophobic barrier that may protect the insects from rain and natural enemies. This is the first time such a use of silk has been found in a biological system.

Crystal structure of raw pure Mysore silk fibre based on (Ala-Gly)2-Ser-Gly peptide sequence using Linked-Atom-Least-Squares method

We have carried out crystal structure analysis of raw pure Mysore silk fibers belonging to Bombyx mori on the basis of model parameters of Marsh et al using Linked-Atom-Least-Squares technique. The intensity of all the reflections were computed employing CCP13 software. We observe that the molecular modification is essentially same as b-pleated structure with antipolar-antiparallel arrangements formed by hydrogen bonds. The essential differences observed in the structure are highlighted and discussed.

Novel silk/poly(butylene succinate) biocomposites: the effect of short fibre content on their mechanical and thermal properties

In the present study, novel short silk fibre ( Bombix mori) reinforced poly(butylene succinate) biocomposites have been fabricated with varying fibre contents by a compression molding method and their mechanical and thermal properties have been studied in terms of tensile and flexural properties, thermal stability, thermal expansion, dynamic mechanical properties, and microscopic observations. The results demonstrate that chopped silk fibres play an important role as reinforcement for improving the mechanical properties of PBS in the present system although raw silk fibres are used without any surface modification normally done to enhance the interfacial adhesion between the natural fibre and the matrix. The tensile and flexural properties of PBS matrix resin are markedly improved with increasing the short fibre content in the composites, showing a maximum value at a fibre loading of 50 wt%. Also, the thermomechanical stability of PBS resin is greatly improved by incorporating reinforcing short silk fibres in the composite matrix, showing much lower linear coefficient of thermal expansion and higher storage modulus than PBS control, respectively. The thermal stability of silk/PBS biocomposites is likely to be intermediate between the PBS matrix and the silk fibre depending on the short fibre content. This work also suggests that use of animal-based natural silk fibres as reinforcement in a natural fibre composite system may be potential for effectively improving the properties and performances of biodegradable polymer matrix resins.

Deposition of bone-like apatite on silk fiber in a solution that mimics extracellular fluid.

The fabrication of apatite-organic polymer hybrids is one of several attractive methods for the development of biomaterials as a substitute for bone. Such materials have both bone-bonding ability and mechanical properties analogous to natural bone. The biomimetic process has focused attention on fabricating such hybrids, where bone-like apatite is deposited on an organic polymer surface in solutions that mimic physiological conditions. In this process, a bone-like apatite layer can be coated onto organic substrates either by using a simulated body fluid (SBF) with ion concentrations nearly equal to those of human extracellular fluid, or by using fluids that are supersaturated with respect to apatite at ambient conditions. In this study, we investigated the ability of natural silk and its related materials to facilitate apatite deposition under biomimetic conditions. Cloths made of raw silk or normal silk fibers were soaked in 1.5SBF, which has 1.5 times the ion concentration of SBF. Sericin film, which is made from an extract of degummed raw silk, was soaked in 1.5SBF. The cloth and the film soaked in 1.5SBF then were characterized by scanning electron microscopic (SEM) observation, energy dispersive X-ray microanalysis (EDX), and thin-film X-ray diffraction (TF-XRD). Apatite deposition was observed on the surface of cloth made from raw silk fiber after it was soaked in 1.5SBF, but it was not observed on cloth made from normal silk fibers. The apatite deposition on the raw silk fiber cloth was accelerated when the fibers were subjected to treatment with CaCl(2) solution at a concentration of at least 1 kmol/m(3) before immersion in 1.5SBF. Apatite deposition also was observed on the sericin film after the film was soaked in 1.5SBF for 7 days. These results indicate that apatite deposition on raw silk cloth is attributable to the catalytic effect of sericin because the surface of raw silk consists of sericin whereas that of normal silk contains fibroin. The deposition of the apatite and its crystal growth are accelerated by the presence of calcium ions on the sericin after treatment with CaCl(2) solution. Thus, sericin on natural silk fiber has the potential to facilitate apatite deposition and can be useful as a polymer material in the fabrication of hybrid materials analogous to bone through biomimetic processes.

絹／ＰＢＳ生分解性複合材料の射出成形と成形品特性

This paper presents a study on injection molded protein fiber reinforced biodegradable composites. Raw silk fiber and polybutylene succinate (PBS) were used as reinforcement and matrix material respectively. The mechanical properties of theses silk/PBS composites and the flow patterns of silk fibers in the molded composites were investigated. Tensile, flexural and Izod impact tests were carried out and the fracture surfaces were observed using SEM. In order to observe the flow patterns of silk fibers in the molded composite, an etching treatment was performed on the surface of the silk/PBS composites using chloroform. The tensile, flexural and Izod impact properties increased with increasing silk fiber volume fraction. The short silk fibers were tangled throughout most of the composite except in the skin layer. In addition, good adhesion was seen in the interface between silk fiber and PBS resin. It is concluded here that the silk fiber can be effectively used as a reinforcement for biodegradable composites.

絹繊維／ポリプロピレン複合材料の射出成形品の力学的性質

Recently attention has been given to shift from glass fiber and carbon fiber to natural fibers as reinforcement for FRP composites with the goal of protect of the environment. This paper concerned with the application of raw silk fiber to reinforcement for composite material. In this study, polypropylene (PP) resin was used for the matrix material and the composites were molded using the injection-molding method. Maleic anhydride grafted polypropylene (MAPP) was also used as the binder resin.Mechanical properties of Silk/PP composites were discussed and compared with standard glass fiber reinforced plastics (GFRP). Furthermore, detailed SEM observation of the cross-section of each molded composite was carried out . As a result, the tensile strength and elastic modulus were found to increase with increasing silk fiber content. In particular, the Izod impact value for the Silk/PP composite was the same as that of GFRP. Moreover, good adhesion between the silk fiber and matrix material was achieved through use of MAPP due to the good reaction between MAPP and the hydroxy groups and amino groups of the silk fiber. However, the dispersion of raw silk fiber was relatively poor in comparison with that of glass fiber in the molded composites.

Inorganic Composition and Thermal Properties of Cocoon Fiber

The changes of color, size and shape of Bombyx mori cocoon shells were observed from 25°C to 550°C. Only 1 % of the original cocoon shell weight remains as cocoon ash after treatment at 550°C. Theinorganic components were detected in the cocoon ashes such as calcium, potassium, sulfur, magnesium etc., using energy dispersion fluorescent X-ray spectrometer analysis system. The thermal properties of B. moricocoon shell subjected to heat-treatment were examined by thermogravimetry-differential thermal analysis-Fourier transform infrared absorption spectrometry (TG-DTA-FTIR) and scanning electron microscopy (SEM). Chemical changes started gradually at around 180°C, and a sharp decrease in weight was observedaround 280°C by TG curves. The IR bands appearing around 2380cm-1 (-OH stretching), 1760cm-1 (C=Ostretching), 1503cm-1 (N-H stretching), 1085cm-1 (C-N stretching) and 965cm-1 (-NH2 stretching) become stronger as an exothermic reaction around 280°C takes place. This is probably due to the cleavingof the main chain and the accompanying decomposition of the cocoon fibers. Similarly, a SEM micrographof raw silk fibers treated at 300°C shows a microtubule in the middle of the fibers of about 25μm diameter.This suggests that the thermal reactions starts in the middle of the fiber and forms a microtubule.

Structural changes by heating and steaming in raw mulberry silk fibers reeled from the cocoons subjected to different drying conditions

Structural changes by heating and steaming in raw mulberry silk fibers reeled from the cocoons subjected to different drying conditions

Some properties of raw silk fibers treated with tanning agents and polyphenoloxidase

Some properties of raw silk fibers treated with tanning agents and polyphenoloxidase