The structure and molecular conformation of model compound copolypeptides related to silk sericin, which were polymerized in acetonitrile or in dioxane system, were investigated by means of infrared spectroscopy, x-ray diffraction and circular dichroism. A close similarity between the model compounds and silk sericin was observed in crystal structure and in molecular conformation. Infrared spectra indicate that the as-polymerized polypeptide related to silk sericin exhibited the anti-parallel β structure. It was demonstrated that model compounds were α mixture of random coil conformation (ca. 50%) and the β structure (ca. 50%) by comparing the observed and calculated circular dichroism curves. Granule forms with a diameter of 0.3-0.5μm were observed for all the as-polymerized model compounds by the scanning electron micrograph.
There is a close relation between damp or oppressive sense and the clingy forces of wet fabrics. In the previous paper the clingy forces were calculated for a geometrical model, given on the assumption in the range of a moderate amount of water content. In this paper, the clingy forces or wettedness were calculated for two geometrical models, given on the assumption in the presence of a large or small quantity of water and the following results were obtained: (1) Three models derived, including one in the previous paper, has common characteristics in the influences of the various parameters on the clingy forces and wettedness of wet fabrics. (2) It was suggested that attractive forces appeared sensitively in the range of low water content and there was a close relation between the hygroscopicity of fibers and the attractive forces. It was assumed that the hygroscopic fibers reduced the attractive forces in the range of low water content, whereas the relation became reversed in the range of high water content. (3) The larger the contact angle of water on the contacting surface and the smaller that of water on the fibers, the smaller the wettedness. The smaller the contact angles of water on both the contacting surface and the fibers, the larger the attractive forces. That is to say, it was suggested that in the range of high water content, which the limit of the wiping off ability by the fabrics was observed, the more wettable the fabrics, the larger the attractive forces.
Lately developments of water absorbent synthetic fibers have become of general interest and the related reports are increasing. In this paper the properties of transmission of water in the related fabrics were estimated from the sliding resistance and the heat flow, the methods of which were derived in the past. It was suggested that water absorption of porous synthetic fiber, the blended of porous synthetic fiber and cotton fiber or the double layer of cotton and polyester contributed to the physical factors of comfort.
A new data collection system was developed by the suitable algorithms for purposes of the detection and evaluation of fabric defects according to the similar procedure to the pattern recognition like the common run of men. Our development system has the performance that is able to retrieve the data of scannings including the abnormal signals only, according to the light scanning system in the fabric width direction by using the light spot having high resolving power, in the first place. In the next place, the defect patterns are made by data setting of these scannings with abnormal signals. The shapes, sizes, existing positions and distribution of the electro-optical output levels of the abnormal points of defect patterns are obtained by the pattern recognition procedures like the Mesh dividing method or Sequential dividing method. Then, the algorithms of this system are organized by mean of the following three parts. 1. The variations of mean values of electro-optical output in each scanning in the fabric feeding direction and the histograms of electro-optical output in the scanning direction for the proper length of the normal fabric part are calculated. The DC bias superposed on the electro-optical output from the former and the standard deviation σ needed for detecting defects from the latter are obtained respectively. 2. The abnormal levels corresponding to the defects in each scanning electro-optical output are detected. For the purpose of these processings, the DC bias obtained according to algorithm 1 are eliminated from the electro-optical output and the histograms with 32 classes are made by the integrating results in each enlarged ripple parts. Next, the upper and lower limits of histograms in each scanning are set up by K times as much as standard deviation σ of histogram for the normal part of fabric, and the existing position, size and level of abnormal signals that are beyond over these limits of the histograms are regarded as the informations of defects and discriminated. 3. The shape, size, existing position and distribution of the electro-optical output levels of abnormal points of the defect patterns that are made by data setting of the scannings with the abnormal signals are recognized. It is said that our development system realizes these algorithms in good agreement with the experimental results for some specimens.
A photometric measurement of the rate of dyeing was carried out with an attachment consisting of two multiple optical glass fibers. Oneside terminals of the optical fibers were dipped in the dye solution facing to each other in a short distance, and the other terminals were set toward the light source and the phototube, respectively in an electrophotometer. As the optical absorbance of dye solutions was instantaneously measured and recorded, an experimental error due to a time-lag of measuring which arises in the usual method when changing the dye concentration were able to be completely avoided. The rate constant of dye exhaustion was estimated quickly from the recording data according to the convenient equations derived from the exponential or the hyperbolic formula.
The molecular conformation of silk fibroin was investigated by infrared spectroscopy (IR) and circular dichroism method (CD). The silk fibroin in the liquid phase was found to have random coil structure containing a small amount of α helix. The α helix content of silk fibroin, dispersed in pure water, increased with increasing the periods during fifth instar of silkworm larvae. This fact was related to the increase of the water content in liquid silk fibroin. Silk fibroin hydrolyzed by aqueous HCl solution showed the strong IR absorption band assigned to β structure as well as the weak band at 620cm-1 (amide V) attributing to α helix. The results of IR and CD suggest that the peptide chains consisting of α helix do not exceed several units, taking into account the x-ray diffraction pattern exhibiting no α-helical chains.
The purpose of this paper is to get an X-ray diffraction pattern of the fiber (about 100% sericin) of Nd-s silkworm without influence of the crystallization of sericin by water during the spinning. From the silkworm, a fiber was spun at 25°C and a velocity of the wind 20-50cm/sec and in the atmosphere of 35, 50, 65 and 85% relative humidity (R. H.). X-ray diffraction pattern of the fibers was measured to find out a R. H. range for the spinning without crystallization. The X-ray diffraction pattern of the fibers spun in the atmosphere of 35 and 50% R. H. showed an oriented amorphous structure. In case of the 65 and 85% R. H., the crystallization of the silk fiber occurred. The results indicate that the amorphous structure of the silk fiber spun in the atmosphere below 50% R. H. is maintained without being affected by water.