Ions eluted from leathers and their corrosiveness to metals / Yasumasa Chonan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXVII, N° 11 (11/1992)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXVII, N° 11 (11/1992) . - p. 409-418 Titre : Ions eluted from leathers and their corrosiveness to metals Type de document : texte imprimé Auteurs : Yasumasa Chonan, Auteur ; Hiroshi Okamura, Auteur ; Keiji Yoshimura, Auteur Année de publication : 1992 Article en page(s) : p. 409-418 Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : It is well known that metals annexed to leathers are easily corroded and various kinds of troubles come from this corrosion. However, the reasons for this corrosion have not been clarified. The present study has been made only for chrome-plated steel pipes. In the corrosion of steel annexed to leather, chloride ion eluted from leather is considered to be the main factor for the corrosion except in a few cases. In addition to chloride ion, eluted sulfate ion is thought to be the secondary factor although its effect on corrosion was observed although much chloride ion was eluted. This may be explained by the fact that there is no contact between a steel pipe and eluted chloride ion due to limited water vapor permeability of a leather surface in contact with a steel pipe or there is a painted surface on a pipe. If a different kind of metal is annexed to leather, different kinds of eluted ions may be considered to be responsible for corrosion of the metal. En ligne : https://drive.google.com/file/d/18E_G0g4h7a0lfM_iHu4ZUIpsPJIp9pv0/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8268 [article]

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Observation of skins, hides and leathers with scanning electron microscope, IV. Changes in pig skins during bating process / Kohkichi Uehara in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXII (Année 1987)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXII (Année 1987) . - p. 33-40 Titre : Observation of skins, hides and leathers with scanning electron microscope, IV. Changes in pig skins during bating process Type de document : texte imprimé Auteurs : Kohkichi Uehara, Auteur ; Harukazu Toyoda, Auteur ; Yasumasa Chonan, Auteur ; Hiroshi Okamura, Auteur Année de publication : 1987 Article en page(s) : p. 33-40 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The changes of the grain structure in pig skins during the bating process were observed with the scanning electron microscope. In addition, the amount of hydroxyproline released from pig skins during the bating process was determined and some physical properties of the bated skin pieces were measured. The humps of dermal papillae in the delimed skins were slight and the surface of papillae was flat. When the delimed skin was incubated with buffer solutions at pH 7.5 for 4 hr, the papillae swelled and the shapes of the surface were spherical, depresed or wrinkled. At a magnification of below 1,000 times, a new network structure was frequently observed in the surface of papillae of the skin pieces treated with pancreatin of Bacillus subtilis (B. sub) protease. This network was composed of the bundled grain fibrils. The grain fibrils in the delimed skin coalesced with each other and were surrounded with some amorphous substances. When treated with pancreatin, the grain fibrils were clearly exposed and separated from each other as shown by the micrographs only at high magnification. The amount of hydroxyproline released from the skin pieces during the enzyme treatment for 4 hr was less than 1%. The values of surface elongation and strain measured with a Tensometer decreased in the pieces treated with pancreatin or sub. protease. En ligne : https://drive.google.com/file/d/1hLnma872R1W2Xo1wBrRU-eaWWik1yXVB/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8962 [article]

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Size-exclusion chromatography of organic acid-masked aluminum complexes and the determination of combined acid/aluminum ratio of the fractions / Tingyou Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXXI, N° 4 (04/1996)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXXI, N° 4 (04/1996) . - p. 89-94 Titre : Size-exclusion chromatography of organic acid-masked aluminum complexes and the determination of combined acid/aluminum ratio of the fractions Type de document : texte imprimé Auteurs : Tingyou Zhang, Auteur ; Yasuhiro Ishii, Auteur ; Kunio Shirai, Auteur ; Yasumasa Chonan, Auteur ; Eisuke Takata, Auteur Année de publication : 1996 Article en page(s) : p. 89-94 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Four kinds of preparations of masked aluminum complexes were prepared by adding sodium citrate at 1:2, sodium tartrate at 1:2, sodium acetate at 1:4 and 3:1 equivalents to aluminum equivalent. The masked preparations were separated by size-exclusion chromatography and the fractions were analyzed for aluminum content by atomic absorption spectroscopy and for combined organic acid by ion chromatography. More than 50% of the added citrate or tartrate was taken up as an aluminum complexed component. A major proportion of polynuclear complex species combined the described acid at 0,2-0,6 equivalent ratio in the preparation. The effect of tartrate was so remarkable that it produced a considerable amount of enlarged molecular-sized complexes with tartrate content 0,6-0,8 in equivalent ratio on one hand and also produced a certain amount of small molecular-sized complexes with high tartrate contents increasing toward 1,0 in equivalent ratio on the other hand. Uptake of acetate by aluminum complex molecules was only 2,5% of the added acetate even at the addition at 3:1 equivalent ratio. However, such a high concentration of acetate broke down the size of aluminum complexes in the solution. En ligne : https://drive.google.com/file/d/1sb13MvLfeYz78roZ4HaFVvZVbHVv2eXe/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=7798 [article]

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Solubilization of cattle and pig hair keratins by reduction with sodium thioglycolate or oxidation with performic acid / Kohkichi Uehara in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXI (Année 1986)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXI (Année 1986) . - p. 331-337 Titre : Solubilization of cattle and pig hair keratins by reduction with sodium thioglycolate or oxidation with performic acid Type de document : texte imprimé Auteurs : Kohkichi Uehara, Auteur ; Ayako Matsunaga, Auteur ; Katsuhiko Arai, Auteur ; Harukazu Toyoda, Auteur ; Yasumasa Chonan, Auteur Année de publication : 1986 Article en page(s) : p. 331-337 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : With the intention of utilizing solubilized keratins as a biomaterial, the solubilities of cattle and pig hair keratins were studied. Samples of hair were collected from steer hides and pig skins with razors and treated with sodium thioglycolate or performic acid. The effects of concentration of the reducing or oxidizing agent, incubation temperature and time on the solubility of hair keratins were examined. The results obtained were compared with those of human hair reported previously. About 60% of steer hair keratins and 50% of pig hair keratins were dissolved in 0.1M sodium thioglycolate at pH 11 and 35°C after 24 hr incubation. When oxidized with 90% formic acid - 3% hydrogen peroxide, the solubilities of steer hair and pig hair keratins were about 75% and 50% after 6 hr incubation, respectively. When the residues from hair oxidized with performic acid were incubated 0.2M sodium carbonate, additional keratins were dissolved. The total amount was about 95% of steer hair and 90% of pig hair after 24 hr incubation. En ligne : https://drive.google.com/file/d/1dwYqGgXqVaCjvEuPraCMvh3vW2YTM39Q/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9191 [article]

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