• Journal of Sericultural and Entomological Science
• /
• v.34 no.2
• /
• pp.41-51
• /
• 1992

In this thesis, both soap and enzymatic degumming method were adopted and the optimum degumming conditions were obtained. Difference between the two degumming methods in silk fiber state was investigated and analyzed on the basis of the results of physical testings, polarizing microscopy, scanning electron microscopy, viscosity measurement, (${\alpha}$＋$\varepsilon$) amino group contents measurement, birefringence measurement, amino acid analysis, thermal analysis, infrared spectroscopy and x-ray diffraction analysis. The results obtained were summarized as follows; Physical test results of the degummed silk fiber showed that the tenacity and the elongation of enzymatic degummed silk fiber were lower than those of soap degummed fiber. But SEM observation and amino acid analysis showed almost the same tendency in the two degumming methods. The viscosity of enzymatic degummed silk fiber was lower than that of soap degummed fiber, but (${\alpha}$＋$\varepsilon$) amino group contents was higher in the enzymatic degummed fiber. It can be suggested that the enzymatic degummed silk fibroin was more degraded than the soap degummed fibroin. The birefringence, endothermic temperature of DSC spectrum, IR crystallinity and X-ray lateral order factor of enzymatic degummed silk fiber were higher than those of soap degummed fiber. It seems that the enzymatic degummed silk fiber has the higher crystallinity than that of soap degummed one according to the above results. However, it can be inferred that these differences between soap and enzymatic degummed fiber would be lessened if pretreatment and aftertreatment were included in the enzymatic degumming process.

• Journal of Sericultural and Entomological Science
• /
• v.28 no.2
• /
• pp.52-60
• /
• 1986

This study was carried out to compare the handle of silk fabrics degummed with Alkalase, Protease produced by bacteria, with of silkfabrics degummed with the soap-soda. 1. In twill habutae, the stiffiness of silk fabric degummed with Alkalase was lower than that of silkfabirc degummed with soap-soda. The soft feeling value which is meaning the total Mandle value of medium fabirc for lady, as well as the Smothness, were more improved in enzymatic degumming than in the soap-soda degumming. 2. In case of Crep De Chine representing thin fabric for lady, the stiffness and Anti-Drape stiffness of the fabric degummed with Alkalase were lower than those of fabric degummed with the soap-soda, but the fullness and the Flexibilit with smooth feeling which is meaning the Total Handle value were higher.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.28 no.1
• /
• pp.19-24
• /
• 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.

• Journal of Sericultural and Entomological Science
• /
• v.29 no.2
• /
• pp.58-66
• /
• 1987

This study was investigated on the effect of degumming of cocoon shell, raw silk yarn and grey silk crepe by use of Papain, comparing with soap, soda and soap-soda. The obtained results may be summarized as follows : 1. Degumming loss, when the pretreatment was done, was completed by Papain more than by alkali. 2. Lousiness result of Papain degummed silk yarn was apt to be improved more than that of alkali degummed one. 3. As a result of tensile property test, elasticity and resilience of Papain degummed crepe were good compared to those of alkali degummed one. 4. Not only bending rigidity of Papain degummed crepe was reduced more than that of alkali degummed one but also hysteresis of bending moment was decreased in papain degummed crepe. 5. Handle of Papain degummed crepe was superior to that of alkali degummed one.

• Journal of Biosystems Engineering
• /
• v.10 no.2
• /
• pp.47-54
• /
• 1985

Performance of a screw press was investigated experimentally with soybeans of various temperatures in order to find out a proper temperature of soybean to extract the oil by the mechanical method. Crude oil extracted by the screw press was chemically analyzed to determine a level of processing the oil for the oil to be used as a fuel for a compression ignition engine. The crude oil was degummed and dried by a plant type laboratory experimental setup to decide whether the processes are effective to improve quality of the oil as a fuel. The degummed oil and the degummed and dried oil were also chemically analyzed and were compared with the crude oil and the commercially degummed and dried soybean oil. The results are as follows: 1. In extraction of soybean oil by a screw press, heating soybeans is effective to increase oil production and to decrease energy consumption of the press. A proper temperature of soybean to extract the oil by the press was determined as about $50^{\circ}C$. 2. Soybean oil production and electric energy consumption of the press are about 83 ml and 58 Wh per 1 kg of soybeans heated to about $50^{\circ}C$, respectively. 3. The quality of crude oil produced by the press is similar to that of the commercially degummed and dried oil. The crude oil does not need to be degummed or dried for use as an engine fuel.

• Journal of Sericultural and Entomological Science
• /
• v.35 no.1
• /
• pp.52-59
• /
• 1993

Raw silk degumming, by which the sericin and other marterials are eliminated from fibroin, is very essential process to produce silk fabrics. Alkali chemicals and enzymes have been used for the silk-degumming process. In this paper, the effect of heat treatment was investigated on silk fibers degummed by two different methods, soap and enzymatic degumming method. The difference between these two degumming methods was analyzed on the basis of results of mechanical testing, thermal analysis and intrated spectroscopy. The tenacity and the elongation of silk fiber are decreased by the heat-treatment in wet state. This tendency is observed in both cases of two degumming methods. The peak temperature in DSC analysis, which is attributed to thermal decomposition of silk fiber, was shifted to higher value with the heat-treatment temperature for the soap degummed silk fiber, however, it was not for the enzymatic degummed one. The IR crystallinity of soap digummed silk fiber is increased with the heat-treatment temperature, while that of enzymatic degummed fiber is not.

• Journal of Sericultural and Entomological Science
• /
• v.28 no.1
• /
• pp.66-71
• /
• 1986

The studies were carried out to screen the optimum conditions for enzymatic degumming of raw silk yarn and silk fabric by use of Alkalase, a protease produced by Bacteria, comparing with Papain and Trypsin representing natural proteolytic enzymes. 1. The optimum temperature and acidity of degumming solution were 70$^{\circ}C$, pH 5-6 for Papain degumming, 40$^{\circ}C$, pH 8 for Trypsin and 50-60$^{\circ}C$ pH 8-9 for Alkalase. 2. By increasing the Alkalase concentration in the range of 0.6 to 1.0 gram per liter, the time for enzymatic degumming of silk yarn could be reduced by 40 minutes. 3. In degumming of silk yarn by Alkalase, the pretreatment of 95$^{\circ}C$, 10 minutes at 0.1% sodium bicarbonate solution or posttreatent of 80$^{\circ}C$, 20 minutes at 2% (o.w.f.) sodium silicate solution improved the efficiency of enzymatic degumming, as compared to that of nontreatment. 4. The breaking strength, elongation and Lousiness results of enzymatically degummed silk yarn were apt to be improved more than those of soap-degummed one. 5. When the pretreatment of alkaline solution was done with over 20% of degumming ratio, the enzymatic degumming efficiency of both Havutae and Crepe de chine could be reached to the same level with those of soap-soda degummed. 6. As the pretreated silk fabric with 20% of degumming ratio was under action of three proteases, respectively, the deumming efficiency of Havutae and Crepe de chine were completed by Alkalase more than by Papain or Trpysin. 7. The stiffness of enzymatically degummed Crepe de chine was not only reduced by 17% more than that of soap-soda degummed one but also the Drape coefficient was decreased in enzymatically degummed fabrics, which was closely related with the soft touch of degummed fabrics.

• Textile Coloration and Finishing
• /
• v.22 no.4
• /
• pp.349-355
• /
• 2010

To investigate the half-degumming of raw silk, the degumming was carried out with soap or sodium carbonate or sodium bicarbonate and some mixed agents at $80^{\circ}C$ for 15 and 30 minutes. With soap of 20~25%o.w.f. degumming losses were about 7~12%. Degumming losses with sodium carbonate of 2~5%o.w.f. were about 6~15%. And about 6~12% wright losses were observed in the degumming with sodium bicarbonate of 20~30%o.w.f. In the degumming with the mixed degumming agents of soap and sodium carbonate, degumming losses were 9~15% with 5%o.w.f. soap and 2~5%o.w.f. sodium carbonate. Sodium carbonate was more effective on the removal of sericin from raw silk than soap. During drying generally half degummed silk yarns stuck together to result in harsh and hard lumps by the adhesion and solidification of the residue sericin of partially degummed silk. Sodium hydrosulfite in degumming agent effectively protected the adhesion of half degummed silk yarns.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.26 no.1
• /
• pp.54-60
• /
• 2013

The partial degumming of silk has recently attracted researchers' attention because of its ability to produce silk textiles with new tactile properties, intermediate between the softness of fully degummed silk and the hardness of raw silk. However, it is difficult to obtain partially degummed silk in a homogenously degummed state due to the heterogeneous character of sericin removal. It is also difficult to examine the homogeneity of degumming. In the present study, Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR) geometry was used to evaluate the effect of processing conditions on the degumming of silk yarns. The crystallinity index, calculated from FTIR spectra, showed an increase with the degumming ratio. Therefore, the homogeneity of degumming could be evaluated by the variation of crystallinity index for 30 different spots in silk yarns. The homogeneity of degumming was influenced by the total degumming time, the content of surfactant, and the liquor rate. No effect was observed upon changing the number of degumming cycles at the same total degumming time.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.27 no.5
• /
• pp.517-523
• /
• 2003

We studied the physical properties of silk fabrics after degumming, the dyeability and the color fastness of silk fabrics after degumming and sericin fixing. As the sericin was removed from silk fabrics, the rate of weight loss increased and both the abrasion resistance and the drape coefficient decreased. This means that the amount of the sericin remained in silk fabrics significantly affects the physical properties of silk fabrics. On the surface and the cross-section of silk fabrics, the silk fibers enclosed by the sericin seemed to be in a lump shape. Each fibroin strand, however, got scattered, as the process of degumming went through. The dyeability of silk fabrics degummed decreased at between 20$^{\circ}C$∼80$^{\circ}C$ the dyeing temperature, on the other hand, it significantly increased over 80$^{\circ}C$. The dyeability of the sericin-fixed silk fabrics was lower than that of the non-serin-fixed silk fabrics, to a little extent. The colorfastness of crocking in the dyed-silk fabrics was a little low and that of the sweat was much lower in a basic sweat. Especially, the colorfastness of the partially degummed silk fabrics was low, because the sericin was not stable in the condition of sweat. Therefore, the process of sericin fixing is essentially required, for the partially degummed silk fabrics and the process of degumming itself.