• 한국염색가공학회지
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• 제1권1호
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• pp.1-6
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• 1989

The reaction of silk with a disulfide-containing crosslinking agent, i.e. bis($\beta$-isocyanatoethyl)disulfide(BIED), was studied in an attempt to obtain disulfide-crosslinked silk. The setting properties of disulfide-crosslinked silk fibers were studied. The permanent set values of single fibers were evaluated after the set fibers were relaxed in boiling water. When single fibers were set in boiling water or in boiling alkaline solution, the permanent set values of BIED-treated silk fibers were less than those of untreated silk fibers. When the fibers were treated with 2% thioglycolic acid solution at $60^\circ{C}$ followed by oxidation, settability of BIED-treated silk was better than that of untreated silk. The rearrangement of secondary bonds faciliated by cleavage of crosslinks as well as the rearrangement of crosslinks itself seems to be an important role in the set stability.

• International Journal of Industrial Entomology and Biomaterials
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• 제45권2호
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• pp.70-77
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• 2022

Wet-spun regenerated silk fibroin (RSF) fibers have been extensively studied owing to their 1) useful properties as biomaterials, including good blood compatibility and cyto-compatibility; 2) the various methods available to control the structural characteristics and morphology of the fiber, and 3) the possibility of fabricating blended fibers and new material-embedded fibers. In this study, silk nanofibrils prepared using a new method were embedded in RSF to fabricate wet-spun silk nanofibril/RSF composite fibers. Up to 2% addition of silk nanofibril, the silk nanofibril/RSF dope solution showed slight shear thinning, and the G' and G" of the dope solution were similar. However, above 3% silk nanofibril content, the viscosity of the dope solution significantly increased. In addition, shear thinning was remarkably evident, and the G' of the dope solution was much higher than the G", indicating a very elastic state. As the silk nanofibril content was increased, the wet-spun silk nanofibril/RSF composite fiber became uneven, with a rough surface, and more beaded fibers were produced. Scanning electron microscopy observations revealed that the beaded fibers were attributed to the inhomogeneous dispersion and presence of agglomerates of the silk nanofibrils. As the silk nanofibril content and RSF concentration increased, the maximum draw ratio decreased, indicating the deterioration of the wet spinnability and post-drawing performance of silk nanofibril/RSF.

• 한국잠사곤충학회지
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• 제34권1호
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• pp.49-56
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• 1992

반응개시제로 potassium persulfate를 사용하여 견섬유에 MAA를 처리하였을 때의 반응 mechanism을 구명하기 위하여, 열분석과 일련의 기구분석을 행하였으며, 이 중 열분석에 의해 얻어진 결과는 다음과 같다. Differential scanning calorimeter 관찰로부터는 metharcrylamide에 의한 가공견섬유는 견 fibroin과 methacrylamide polymer의 열분석에 의한 peak가 뚜렷하게 분리되어 나타났으며, 가공율이 증가함에 따라 두 peak가 모두 고온측으로 이동하는 것으로 나타났다. 가공견섬유의 흡습율은 가공율이 증가함에 따라 증가하였다.

• 한국잠사곤충학회지
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• 제33권2호
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• pp.82-86
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• 1991

반응개시제로 potassium persulfate를 사용하여 methacrylamide(MAA)를 견섬유에 처리함에 있어서 그 반응 mechanism을 규명하기 위한 기초자료를 얻기 위하여 monomer의 농도, 개시제의 농도, pH, 용비, 반응시간 등의 반응조건을 달리하여 무게증가율을 관찰하였다. 얻어진 결과를 요약하면, MAA 가공견사는 monomer 농도에 비례하여 무게가 증가되었으며, 개시제로 사용한 potassium persulfate의 농도는 1.7% 부근에서 무게증가율이 최대값을 보였으며, buffer 용액을 사용한 반응용의 초기 pH 값은 3.8 부근에서 무게증가율이 최대값을 나타내었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제28권1호
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• pp.19-24
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• 2014

Silk has always been one of the most favored textile materials. Fully degummed silk fiber (i.e., silk fibers without sericin) shows better luster than raw silk fiber (with sericin); it is also softer. On the other hand, raw silk fiber feels cooler because of the presence of sericin, making it useful as a textile for the summer season. Recently, partially degummed silk has attracted researchers' attention because it provides better luster, feel, and dyeing properties. However, the partial degumming of silk is very difficult because it results in inhomogeneously degummed fiber. In the present study, silk yarns were degummed with surfactant aqueous solutions and the effects of each surfactant on the degumming ratio, crystallinity, and homogeneity of the degummed silk yarn were examined. The degumming ratio and crystallinity index of silk yarn varied depending on the type of surfactant. On the whole, anionic surfactants resulted in higher degumming ratios and better homogeneity than nonionic surfactants.

• International Journal of Industrial Entomology and Biomaterials
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• 제26권2호
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• pp.81-88
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• 2013

Wet-spun silk fibers have attracted the attention of many researchers because of 1) the unique properties of silk as a biomaterial, including good biocompatibility and cyto-compatability and 2) the various methods available to control the structure and properties of the fiber. Cellulose nanofibrils (CNFs) have typically been used as a reinforcing material for natural and synthetic polymers. In this study, CNF-embedded silk fibroin (SF) nanocomposite fibers were prepared for the first time. The effects of CNF content on the rheology of the dope solution and the characteristics of wet-spun CNF/SF composite fibers were also examined. A 5% SF formic acid solution that contained no CNFs showed nearly Newtonian fluid behavior, with slight shear thinning. However, after the addition of 1% CNFs, the viscosity of the dope solution increased significantly, and apparent shear thinning was observed. The maximum draw ratio of the CNF/SF composite fibers decreased as the CNF content increased. Interestingly, the crystallinity index for the silk in the CNF/SF fibers was sequentially reduced as the CNF content was increased. This phenomenon may be due to the fact that the CNFs prevent ${\beta}$-sheet crystallization of the SF by elimination of formic acid from the dope solution during the coagulation process. The CNF/SF composite fibers displayed a relatively smooth surface with stripes, at low magnification (${\times}500$). However, a rugged nanoscale surface was observed at high magnification (${\times}10,000$), and the surface roughness increased with the CNF content.

• 한국염색가공학회지
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• 제21권1호
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• pp.67-72
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• 2009

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$^{\circ}C$ for 60min. The effective sericin fixation was obtained by treating at $60{\sim}80^{\circ}C$ 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.

• 한국잠사곤충학회지
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• 제37권1호
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• pp.39-45
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• 1995

메타크릴아미드에 의해 38% 증량처리 된 견섬유에 대하여 물성 및 실용적 성능을 조사하여 다음과 같은 결과를 얻었다. 1. MAA graft 가공처리에 의해 견사는 강도, 신도, modulus와 toughness 등의 역학적 물성값은 감소하였으며, 마찰계수는 증가하였다. 2. MAA graft 가공처리에 의해 견사의 수분율은 증가하는 것으로 나타났으며, 따라서 마찰대전압과 반감기의 값도 줄어들어 정전기에 의한 장애를 줄일 수 있다. 3. MAA graft 가공처리에 의해 견직물은 인열강도가 떨어졌으나, 강연도와 방추도는 증가하였다.

• International Journal of Industrial Entomology and Biomaterials
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• 제33권2호
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• pp.132-137
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• 2016

Although silk textile shows excellent performance when used in clothing over a long period, its limited elongation and elasticity have restricted its extension to other textile and non-textile applications. In the present study, silk textile was produced using silk/polyurethane core-spun yarn and degummed to enhance its elongation and elasticity. The effects of degumming on the structure and mechanical properties of the silk textile were examined. Scanning electron microscopy observation revealed that the silk filaments became finer and more flexible with degumming, resulting in increased tangling of weft yarns and a highly shrunk textile structure in the weft direction. Although the strength of the degummed silk textile was decreased, its elongation greatly increased by 383% (a 16-fold increase) because of the degumming treatment. In particular, the elasticity of the silk textile was greatly improved. The silk textile exhibited ~30% reduction in the elongation after the second extension; however, the elongation almost did not change after 18 additional extension-recovery tests.

• Fibers and Polymers
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• 제7권2호
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• pp.180-185
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• 2006

A pineapple protease, bromelain, was used to improve the dyeing properties of protein fibers such as wool and silk. The optimal condition for the activity of the pineapple protease was about $60^{\circ}C$ at pH 7. The wool and silk were treated with the protease extracted from a pineapple and the K/S values of the dyed wool and silk were measured using a spectrophotometer in order to compare the dye uptake. The protease treatment enhanced the dyeing properties of protein fibers without severe changes in mechanical properties. The surface appearances of protease-treated fibers were observed by microscopy.