The interaction of metal ion with sericin was investigated by ultramicro-electrophoresis, X-ray diffraction, IR-spectra, DTA and pH titration.
The following results were obtained:
1) In the pH region lower than isoelectric point, both sericin bind with Sn²⁺ and Th⁴⁺ but not with Cd²⁺ and Al³⁺. Similar tendency was found with sericins prepared under the different condition. The binding amount of metal ion to sericin was less than that in alkaline region.
2) From the results of pH titration of metal salts and of electrophoresis of metal ion-negative AgI sol (pI 4), it is concluded that SnCl₂ is hydrolyzed in the pH region lower than the isoelectric point of sericin and Al(NO₃)₃ is hydrolyzed in the higher pH region. It was found that free energies of binding to AgI sol for Sn²⁺ and Al³⁺ are as large as that of Th⁴⁺. These results are in good agreement with those in electro-phoresis for sericin bound with metal ions.
3) In sericin cocoon layers treated with Al(NO₃)₃ or Th(NO₃)₄ at pH 6.0, two endothermic peaks were observed at about 233°C and 270°C (dec. temp.), while that treated with Th (NO₃)₄ at pH 2.5 had a single endothermic peak and the decomposition temperature was lowered to 253°C.
4) The strong scattering was observed about the center (d>12.5A) in X-ray diffraction pattern of sericin cocoon layer treated with Th (NO₃)₄ at pH 2.5.
5) At both pH 2.5 and pH 6.0, poly-L-glutamic acid bound easily with Th⁴⁺, while poly-L-lysine almost did not bind with Th⁴⁺ at pH 2.5.

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Conformational change of poly-L-serine, as a model compound related to sericin, accompanied by heat treatment under humidity was investigated by means of a differential scanning calorimeter (DSC), thermogravimeter (TG), an infrared spectrometer and an x-ray diffractometer. Water was absorbed and tightly bounded to the void in a crystalline region or an amorphous region of poly-L-serine by the heat treatment in the presence of water. TG and DSC measurements indicated that the water was eliminated in the course of heating at above 200°C. It was confirmed that the degree of reorientation of the side chain and the interaction between β-sheets, which were formed by corss β molecular chain, increased during the heating.

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Thermal properties of sericin prepared by various methods were investigated by means of X-ray diffraction, Infrared spectroscopy, DTA and ultramicro-electrophoresis.
The following results were obtained.
1) On X-ray and IR-spectrum studies no significant difference was observed among sericin fractions prepared by modified Mosher methods with various times and temperatures. But the isoelectric points differed a little among these sample, and the isoelectric point of A-fraction prepared with shorter time was in an alkaline side compared to those of others.
2) The thermal decomposition of sericins began to occur at 200_??_220°C. In an earlier stage of decomposition, the increase of absorption intensity of 1720cm^-1 and the decrease of solubility were observed. The absorption intensities at 1230cm^-1 and 1060cm^-1 and the absorption intensity ratio of Amide (II/I) remarkably decreased when the crystallites were broken.
3) The sericins prepared by modified Mosher method decomposed thermally at about 260_??_270°C. The decomposition temperature of B-fractions were about 10°C higher than those of A-fractions and that of sericin prepared with the shortest time was about 10°C lower than those of others.
4) The cocoon layer of nd silkworm decomposed thermally at 258°C, but its powder had double endothermic peaks at 232°C and 266°C as well as the sericins prepared by modified Mosher methods.
5) The sericin extracted from the silkgland of nd×Taizo silkworm had double endothermic peaks at 286°C and 308°C. These correspond to the patial degradation and the weak crystal transition.
6) The sericin separated by stirring aqueous silk protein solution showed β-structure, and the thermal decomposition occured at 314°C.
From the above results, it is concluded that the decomposition temperatures depends on the crystallinity, and the sericins prepared from the silkgland and aqueous silk protein solution shows higher decomposition temperature due to contamination of fibroin.

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Adsorption behaviours of various surface active agents, anionic, cationic and nonionic, were studied by the microelectrophoresis. It was found that, when polar groups of surface active agents were the same, the free energy of adsorption increased with increasing chain length, and was greater for anionic than for cationic surface active agent. No difference was found between adsorption behaviours of surface active agents, unlike those of thorium ions on sericin A and B.
The nonionic surface active polymers of the pluronic type, EPAN's, were found to behave as anionic surface active agents, when their effect on uncovered sols were examined. However, no adsorption was found to take place on sol particles covered with sericin.
Electron micrograph showed that the morphology of the coagulum of silver iodide sol covered with sericin, obtained by the addition of ionic surface active agents, was very different from that obtained by the direct addition of sericin or inorganic electrolyte to the silver iodide sol uncovered.

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The interaction of surface active agents with sericin has been studied with regard to reelability of cocoon in the process of raw silk production.
The following results were obtained.
1) Anionic and cationic surface active agents were adsorbed on sericin at co-ion regions respectively, and the adsorption of the later took place at pH2.5 where COOH groups of sericin scarecely dissociated.
2) In the co-ion region, the charge density of AgI sol particles covered with sericin became noticeable at about 10^-4M concentration of surface active agents, and at about cmc it increased remarkably. Also, the surface active agents which have the same polar groups increased the charge density of AgI sol particles covered with sericin at lower concentrations with the increase in chain length of alkyl groups.
3) The increment of charge density of AgI sol particles covered with sericin by adsorption of surface active agents was observed in the order of counter ion>isoelectric point>co-ion region. This was also found in the adsorption test using cocoon layers.
4) The effect of surface active agents on the swelling ratio of cocoon layer was in the order of co-ion>isoelectric point>counter ion region. In the counter ion region, the swelling ratio decreased at around the concentration at which the charge of sericin was neutralized with surface active agent, while in the co-ion region it increased remarkably at about cmc. Similar phenomena were found in the solubility test of sericin with sodium lauryl sulfate.
From these results, it is concluded that the interaction of surface active agent with sericin is due to both van der Waals force and electrostatic force (Coulomb's force) and the swelling ratio of cocoon layer treated with surface active agent is influenced by intermolecular electrostatic repulsion of sericin due to the adsorption as well as by lowering of the surface tention or contact angle etc.

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In order to examine the interfacial-chemical properties of silk proteins, the coagulation and protection on positive silver iodide sol by fibroins at various pH and ionic strength were investigated.
The native fibroins were extracted from the posterior section (p-fibroin) and the middle section (m-fibroin) of the silk gland of B. mori larva at the third day of the fifth instar. The regenerated fibroin (r-fibroin) was prepared from native cocoon layer. The following are the results obtained,
1) The isoelectric points determined by ultra-micro-electrophoresis are in the pH value of 3.7 to 4.0 for both native and regenerated fibroins. There is no marked difference between the two fibroins and these values were in good agreement with these found by the experiments on the protection.
2) Both m-fibroin and r-fibroin coagulate the sol in all the region of pH, while p-fibroin coagulates only when p-fibroin and the sol particle charged oppositely with each other. However, when the ionic strength of the sol is increased the coagulation occurs even in the pH-region where p-fibroin and the sol particle have the same charge.
3) Both m-fibroin and r-fibroin protect the sol, but p-fibroin does not. The protection effect decreased in the neighborhood of the isoelectric point and the extent of the decreases was less than in the case of sericin.
4) The stability factor in the pH-region where fibroin and sol particle charge oppositely with each other is lower than in the pH-region when they are in the same charge. The stability factor is almost equal to unity in agreement with the theory of rapid coagulation.
5) It is therefore presumed that the molecular weight of both m-fibroin and r-fibroin is equal and but that of p-fibroin is lower than that of both of them.

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水あるいは有機溶剤の存在のもとで熱処理することにより生ずる絹セリシンの分子形態変化を示差走査熱量測定 (DSC), 赤外吸収スペクトルおよびX線回折測定により検討した。水および有機溶剤処理により, ランダムコイル構造はβ構造へと転移した。エタノールあるいはアセトン処理よりも水処理により, 試科のβ構造含有率が高い値を示すようになった。

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後部絹糸腺から抽出したフィブロイン水溶液とCu-En法によって生糸より調製したフィブロイン水溶液から, 種々の方法で凍結乾燥を行ないその結晶構造と熱的性質について検討し次の結果を得た。
1) 後部絹糸腺から抽出したフィブロインは, 水溶液または凝集沈殿物の凍結乾燥物ともにβ構造を示した。IRスペクトルのアミドIの吸収は両試料とも1650cm^-1と1630cm^-1に認められた。また熱分解温度は318～320℃であるが, 分解開始温度が低く, 熱分解は段階的に進んだ。
2) 生糸からCu-En法で調製したフィブロイン水溶液を直接凍結乾燥したものは非晶性であり, アミドIの吸収は1660cm^-1に生じた。そしてその分解温度は305℃であった。また, 示差熱曲線において180～230℃に巾広いが弱い吸熱ピークが認められ, ここでX線図形はβ型に変わり, アミドIの吸収は新らたに1630cm^-1付近にも認められた。
3) 生糸からCu-En法で調製したフィブロイン水溶液をアルコールで沈殿させたものの凍結乾燥物はX線的にβ型であり, アミドIの吸収が1650cm^-1と1630cm^-1付近に認められ, 分解温度は315℃であった。また, 硫酸アンモニウムを加えて沈殿させたものの凍結乾燥物はX線的にα型であり, アミドIの吸収は1645cm^-1にのみ認められた。また分解温度は310℃で, 加熱によるβ型への転移は生じなかった。
4) 精練糸のアミドIの吸収は1660cm^-1と1630cm^-1付近に認められ, その分解温度は350℃であった。なお1700cm^-1付近に生じた吸収を除いては, 凍結乾燥フィブロインとほぼ同じような吸収スペクトルが得られた。
一般に, 加熱によるIRスペクトルの変化は, 昇温に伴ない1710cm^-1付近の吸収が生じ, 分解時にアミドIIとアミドIIIの吸収強度が顕著に減少した。

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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.

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セリシンを土壌改良剤として応用するため, 種々の土壌粘土を供試し, 粘土サスペンジョンの凝集作用と電気泳動におよぼす作用, ならびにセリシン吸着量を測定して粘土粒子への結合機構をしらべた。そしてこれらの結果が土壌の耐水性団粒生成にどのように対応するかを合せて検討し, 土壌改良を目的とした結合物質としてのセリシンの作用特性を検討した。
1) 粘土粒子とセリシン電荷が異符号の領域では, セリシンの吸着によるζ電位の中和にもとづく凝集が見られる。同符号のpH領域での凝集はセリシンによる架橋結合によるものと考えられ, 凝集効果は各土壌粘土とも現われる。
2) セリシン等電点のアルカリ側での粘土粒子によるセリシンの吸着は, 粒子の正電荷部位への吸着であると考えられ, 吸着量は土壌粘土の鉱物組成によって異なる。
3) 土壌の耐水性団粒生成におよぼすセリシン濃度の影響については, セリシンの吸着による強固な粒子間結合による0.25mm以上の有効団粒形成がセリシン濃度が増すほど顕著になる。

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Change in the fine structure of Polyester fibers treated with Carriers such as Orthophenyl phenol (OPP) and Methyl salicylate was investigated in relation to the study of organic solvent/water treatment. Furthermore, Polyester fibers heat-set under fixed and relaxed conditions were treated also in the same way.
Crystallinity by density measurement, X-ray diffraction pattern, and crystallite size and lattice spacing of these fibers were investigated. The fibers treated with the Carriers, especially OPP showed a clear reflectance image of (010), (_??_10), (100) and (0_??_1) planes and increases in the crystallite size and the crystallinity.
On the other hand saturation values of C. I Disperse Violet 1 of these fibers also increased by the Carrier treatment. These results are the same as those obtained for the treatment of Polyester fiber with organic solvent/water such as benzyl alcohol/water reported previously.
Carrier treatment of Polyester fiber leads to a considerable change of the fine structure not only in the crystalline region, but also in the amorphous region

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We have previously reported on the treatment of polyester fiber with organic solvent/water. In this paper, high pressure steaming in polyester printing is examined with steam containing a small quantity of organic solvent. Namely, polyester fabric printed with the color paste of C I Disperse Violet 1 was steamed under high pressure with vapors evaporized in a closed chamber from 1%, 5% aqueous benzyl alcohol and butanol solution. Color values of the fabrics steamed with vapors of the mixtures were considerably higher than that obtained by steaming with water alone.
On the other hand, polyester fibers pretreated with vapors of the mixtures were dyed with C I Disperse Violet 1 in water. The partition coefficient and saturation value for the fibers pretreated were higher than those for untreated fiber, especially benzyl alcohol/water pretreatment remarkably increased dye uptake compared to butanol/water pretreatment.
Although there was a considerable difference in dye absorption between the fabrics pretreated with benzyl alcohol/wáter and butanol/water, no difference in the color values after high pressure steaming of the fabric printed with color paste was found between both steaming mediums.
From these results, it seemed that the behavior of color paste during steaming with vapors of the alcohol-water mixtures plays more important role than the structural change of the amorphous region of the fiber for color development in textile printing.

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Nylon 6 fiber was pretreated with butanol/water solutions of various compositions. The dyeing behaviors of the fibers with 1, 4-diaminoanthraquinone in water and perchloroethylene were investigated with reference to changes in fine structure of the fibers.
In the case of dyeing in water, the significant difference in the amount of dye absorbed between the untreated fiber and the fiber pretreated with aqueous 5% butanol solution was not observed. On the other hand, in the case of dyeing in perchloroethylene the dye uptake increased in the following order: untreated fiber<fiber pretreated with butanol<fiber pretreated with water<fiber pretreated with aqueous 2% butanol solution<fiber pretreated with aqueous 95% butanol solution<fiber pretreated with aqueous 5% butanol solution. Also in the both cases of dyeing in water and perchloroethylene the rate of dye absorbed and desorbed increased in the same order as that shown above. In addition, the relations between dyeing temperatures and dye uptakes were investigated.
The results obtained are briefly discussed in terms of the changes in the fiber structure formed during the pretreatment with butanol/water solutions.

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