• International Journal of Industrial Entomology and Biomaterials
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• v.43 no.1
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• pp.16-21
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• 2021

The silkworm cocoon has recently attracted the attention of researchers because of its usefulness as a biomedical material (e.g., usage in the development of the membrane for guided bone regeneration and usage as a starting material for the fabrication of natural silk nonwoven fabric). The silkworm variety and strain have been reported as one of the important factors affecting the structure and properties of silk materials. This study examines the morphology and the molecular conformation of the silkworm cocoon at different cocoon measurement points, as well as the effect of the silkworm strain and rearing season on the morphology and crystallinity of the silkworm cocoon. The results show that the morphology of the outside of the cocoon does not differ depending on the cocoon measurement points, but that of the inside does. The silkworm cocoon crystallinity is not affected by the cocoon division. Interestingly, the crystallinity of the outside of the Jam101 cocoon differs depending on the rearing season, whereas it does not in other silkworm strains.

• Journal of Sericultural and Entomological Science
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• v.17 no.2
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• pp.171-173
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• 1975

This experiment was conducted to study the reasonable deguming method of cocoon on the Boss silk making. The results obtained are as follows： 1. Reasonable deguming method of cocoon on the floss silk making was observed to be about 0.75％ Na$_2$SiO$_3$, 2％ NaCO$_3$ solution during 40 minutes boiling Process. 2. Treatment 6 increased qualities of floss silk and hand spun silk as compared with the other conventional method.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.43-46
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• 1965

This report was prepared to check silk reelalility and its quality when the cocoon was cooked in nonpermeative condition after trotted with some chemical solution. The obtained results were as followings. 1. A new chemical, Serisol, was developed by the author to help silk reelability 2. The chemical cooking method showed 0.4％ increase of silk yield more than the normal silk reeling method. 3. The chemical conducted good cocoon cooking without permeative process. 4. This method showed better cleanness and neatness than the normal one. 5. This method did not damage the silk quality because of use Serisol. 6. The proper dilution of Serisol was found as 2000 times for it.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.57-61
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• 1965

This report was prepared to find how warious tussah silk worm diets effect for the worm nutrition, its cocoon and reelability, Meantime, it was attacked the reeling effect of newly developed tussah cocoon cooking chemical, Tussah-lite. The results obtained are as followings. 1. The chemical composition of various diets were almost even, but Quercus acutissima Carrathers was the best from the nutrition point of view. 2. It was found that the more Calcium Oxalate, the better cocoon was formed, but Calcium Oxalate in the cocoon layer was found as almost same amount in case of different diet was fed. 3. It was also found that the more tannin, the better cocoon was formed, but the cocoon reelability was found as almost same in case of different diet was fed. 4. The cocoon reeling effect of newly developed chemical, Tussah-lite, showed 6∼7% silk yield from the tussah cocoon.

• Journal of Sericultural and Entomological Science
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• v.25 no.2
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• pp.65-68
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• 1984

This survey was to realize the foreign cocoon quality and to provide data for suitable reeling conditions. Cocoons were inported from Taiwan (7 packs) and Hongkong (12 packs) in 1983. The practical inspection and classiffication of above cocoon was performed at Provincial Institute of cocoon testing and tested data were collected to evaluate the cocoon quality. The results were as follows. 1. It showed higher variation of the average raw silk yield percentage and cocoon assorting rate than domestic cocoon. 2. In view of the low quality products, cocoon price was expensive and most of packs were evaluated as inferior grade. 3. It was supposed that importing the superior quality cocoon from foreign country may be contributed to manufacturing of silk commodity of higher grade.

• International Journal of Industrial Entomology and Biomaterials
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• v.40 no.1
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• pp.6-15
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• 2020

Silk has attracted the attention of numerous research groups because of its unique properties as a biomedical material. Recently, studies on the biomedical application of silk cocoon, such as membranes for guided bone regeneration, have been conducted. As a preliminary study on silkworm cocoons, the morphological structure and crystallinity of cocoon of nine silkworm varieties with different sides are examined in this study. The morphological structure of the silkworm cocoon is shown to be dependent on silkworm variety and the cocoon layer (i.e. outside or inside). It is also shown that the silk filaments of the out layer are more bent and twisted compared to those of the inner layer. Furthermore, the crystallinity of the outer surface of all silkworm cocoons is found to be higher than that of the inner surface, regardless of the silkworm variety. Lastly, it is shown that the crystallinity index of the cocoon depends on the silkworm variety, implying that the structure of the cocoon varies with silkworm variety.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.53-58
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• 2004

Studies on heterotic expression in the silk productivity of 66 thermo-tolerant bivoltine hybrids reared under high temperature $(36{\times}1^{\circ}C)$ and low humidity (60${\times}$5%) conditions revealed that manifestation of heterosis was highly significant for majority of the quantitative traits contributing to more cocoon productivity. Observations were made on 8 economically important traits such as fecundity, pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, cocoon filament length and raw silk. Analysis of variance results revealed great deal of variability indicating significant (P < 0.001) variations. Out of 66 hybrids, 7 hybrids exhibited positive heterosis for seven traits and 4 hybrids expressed significant hetero-beltiosis for 6 traits, out of 8 traits evaluated. Based on results, the hybrids ${SR_1} {\times} {SR_5}and {CSR_2} {\times} {SR_5}$ are adjudged as most promising ones and can be exploited commercially in tropical climates to increase the cocoon productivity.

• Journal of Sericultural and Entomological Science
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• v.15 no.1
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• pp.31-35
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• 1973

Strength, elongation and elasticity are essential properties with regard to the tensile properties of raw silk thread. The reasonable harmony of the above three physical characters appears to be the specific nature of the raw silk thread and the dynamical functions are determined by the cocoon filament forming the raw silk. From such viewpoint, the author has studied the tensile property of the thread when the cocoon filament is stretched and transformed. The results obtained are as follows: 1) The stretching strength of the inner layer filament is stronger than that of the outer and medium layer ones. 2) The stretching strength of the filaments is influenced by the moisture-heat denaturalization of cocoon layer sericin in the drying process. 3) The more transformed functions by the stretching become, the lower the elasticity index of the cocoon filament was shown. 4) When cocoon layer sericin is denatured by moisture and heat, elasticity index of the filament is decreased.

• International Journal of Industrial Entomology and Biomaterials
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• v.34 no.1
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• pp.6-10
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• 2017

Dissolution of Antheraea yamamai silkworm cocoon was carried out in various solvent systems with various dissolving conditions including dissolution salts, salt concentration, dissolving temperature, and time. General chaotropic salt for Bombyx mori silk fibroin does not work for A. yamamai silkworm cocoon. Lithium bromide 9.3 M at $100^{\circ}C$ also does not work to dissolve wild silkworm cocoon. However, 9 M of lithium thiocyanate treatment at $100^{\circ}C$ induced 100% dissolution of wild silkworm cocoon. But it could not be dissolved lower than $60^{\circ}C$. Like lithium thiocyanate, less than $60^{\circ}C$ treatment with molten calcium nitrate 4 hydrate could not dissolve wild silkworm cocoon. As the dissolution temperature increased up to $100^{\circ}C$, the solubility of wild one was reached over 90%. SDS-PAGE showed broad tailing stream pattern that means the molecule of wild silk was depolymerized with dissolution temperature and time. From the above results, the best chaotropic salt for A.yamamai silkworm cocoon is calcium nitrate 4 hydrate.

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.35-43
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• 1973

Since automatic silk reeling machine has been used in the fold, silk reeling tension has been considered to be an important matter. Such silk reeling tension affects on the physical nature of silk which would be Wire Silk in case of super high reeling velocity. This will be a report regarding with the silk reeling tension used Korean cocoon and various analyses are carried out where reached to following results. 1. Korean silk is still far from Wire Silk yet produced as general silk. 2. There is more possibility to increase silk reeling velocity if cocoon nature is improved. 3. At present, it is considered that the optimum reeling velocity is to be about 190 r.p.m. which is corresponded with 0.4∼0.5 g/d silk reeling tension. 4. This report has prepared a silk reeling tension contolling diagram against reeling velocity as shown at Figure 7. The mathematical relations between them are; A. in case of total silk reeling tension; Y=5.0831＋0.0381X(Y; total reeling tension, g/21d, X; reeling velocity, m/min) B. in case of initial silk reeling tension; Y=3.1922＋0.0175X (Y; initial reeling tension, g/21d, X; reeling velocity, m/min) 5. The main problems for the increase of silk reeling velocity is considered to be Break Down of Silk Reeling Ends caused by Cocoon Jumping or Cocoon Layer Seperation during the silk reeling work. Such troubles are concerned with the produced cocoon nature.