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INTERNATIONAL LEATHER MAKER (ILM) . N° 54Mention de date : 07-08/2022Paru le : 04/07/2022 |
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Ajouter le résultat dans votre panierAluminium update for leather / Karl Flowers in INTERNATIONAL LEATHER MAKER (ILM), N° 54 (07-08/2022)
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Titre : Aluminium update for leather Type de document : texte imprimé Auteurs : Karl Flowers, Auteur Année de publication : 2022 Article en page(s) : p. 34-36 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Aluminium L'aluminium est un élément chimique, de symbole Al et de numéro atomique 13. C’est un métal pauvre, malléable, de couleur argent, qui est remarquable pour sa résistance à l’oxydation13 et sa faible densité. C'est le métal le plus abondant de l'écorce terrestre et le troisième élément le plus abondant après l'oxygène et le silicium ; il représente en moyenne 8 % de la masse des matériaux de la surface solide de notre planète. L'aluminium est trop réactif pour exister à l'état natif dans le milieu naturel : on le trouve au contraire sous forme combinée dans plus de 270 minéraux différents, son minerai principal étant la bauxite, où il est présent sous forme d’oxyde hydraté dont on extrait l’alumine. Il peut aussi être extrait de la néphéline, de la leucite, de la sillimanite, de l'andalousite et de la muscovite.
L'aluminium métallique est très oxydable, mais est immédiatement passivé par une fine couche d'alumine Al2O3 imperméable de quelques micromètres d'épaisseur qui protège la masse métallique de la corrosion. On parle de protection cinétique, par opposition à une protection thermodynamique, car l’aluminium reste en tout état de cause très sensible à l'oxydation. Cette résistance à la corrosion et sa remarquable légèreté en ont fait un matériau très utilisé industriellement.
L'aluminium est un produit industriel important, sous forme pure ou alliée, notamment dans l'aéronautique, les transports et la construction. Sa nature réactive en fait également un catalyseur et un additif dans l'industrie chimique ; il est ainsi utilisé pour accroître la puissance explosive du nitrate d'ammonium.
Ions métalliques
Précipitation (chimie)
Sels métalliques
Tannage minéralTannage dans lequel interviennent différents minéraux. Le plus répandu est le tannage aux sels de chrome, mais aussi à l’aluminiumIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : There is still a lot of misleading information that exists concerning aluminium. Aluminium is the lightest metal and is often referred to as a light metal. It is extremely common on earth and forms one of the main metal constituents in soil, particularly clay. Kaolin, a well-known clay, has the chemical formula Al2 (OH)4Si2O5. Aluminium metal reacts very rapidly to form an aluminium oxide, Al2O3.
Like all metals, aluminium's use has risen rapidly since the late 1800s, particularly since the industrial revolution. A distinction must be made between the metal, the ion and its salts.Note de contenu : - Metal, ion, and salt
- Dementia and breast cancer
- Aluminium and leather
- Fig. 1 : Aluminium, a silver-coloured metal
- Fig. 3 : Aluminium precipitation
- Fig. 4 : Fraction of soluble AlEn ligne : https://drive.google.com/file/d/1h5nGcUD4o6ERJPuNkpOowi0VKP3EkWhL/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37949
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Code-barres Cote Support Localisation Section Disponibilité 23483 - Périodique Bibliothèque principale Documentaires Disponible Detanning chromium leather waste / Abigail Clare in INTERNATIONAL LEATHER MAKER (ILM), N° 54 (07-08/2022)
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Titre : Detanning chromium leather waste Type de document : texte imprimé Auteurs : Abigail Clare, Auteur ; Karl Flowers, Auteur Année de publication : 2022 Article en page(s) : p. 38-40 Langues : Anglais (eng) Catégories : Cuir -- Déchets
Cuirs et peaux -- Industrie -- Aspect de l'environnement
Déchets industriels -- Elimination
Détannage
Hydrolyse
Tannage au chromeIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In 2019, approximately 341 million hides (9.1 million tonnes) were processed worldwide. For every ton of wet-salted raw material, approximately 600kg of combined wet and dry solid waste is generated, with 200-250kg of this being tanned waste. Tanned wastes contain collagen as the main component and pertain to shavings, splits, trimmings, and buffing dust etc.
Although leather is naturally biodegradable, the tanning process alters the rate of disintegration. By modifying collagen molecules, tanning agents stabilise the protein and slow the degradability of leather relative to raw hides/skins. Therefore, many tanned leather wastes end up in landfill or are incinerated, resulting in environmental impacts (if uncontrolled) on soil and groundwater (and in some cases the release of greenhouse gas emissions). Sustainable tanneries have good controls to prevent these problems, but it is useful to understand how improvements can be made to tanneries who are starting their sustainability journey or to improve those tanneries who already have good controls.
Detanning leather can give rise to alternative disposai routes for tanned solid wastes. By decreasing the degree of modification of the collagen fibres, tanning agents can be recovered and the remaining tan-free product can enter a composting process. Detanning enables the extracted products (collagen and tanning agents) to be recovered, recycled and reused in a circular economy.Note de contenu : - Chromium-containing wastes
- Chromium recovery methods
- Acid hydrolysis
-Alkali hydrolysis
- Enzymatic hydrolysis
- Fig. 1 : Types of tanned leather waste
- Fig. 2 : The detanning process of leather
- Fig. 3 : The modification of collagen fibres during chromium tanning
- Fig. 4 : High Cr concentrations in soils can affect plant growth and development (suppression)En ligne : https://drive.google.com/file/d/143SFY8BVSxJSQdc7_fOlcr-RAREpWt70/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37950
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Code-barres Cote Support Localisation Section Disponibilité 23483 - Périodique Bibliothèque principale Documentaires Disponible
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Titre : Saccharides in leather Type de document : texte imprimé Auteurs : Karl Flowers, Auteur Année de publication : 2022 Article en page(s) : p. 44-45 Langues : Anglais (eng) Catégories : Amidon dialdéhyde
Biomatériaux
Carboxyméthylcellulose
Carraghénanes
Cuirs et peaux -- Finition
Glucides
HémicelluloseLes principaux polysaccharides non cellulosiques du bois. Le bois est constitué d'hémicellulose (28 à 35%), de cellulose et de lignine.
hydrocolloïdes
Lignocellulose
Polymères
Post-tannageIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The November/December 2020 issue of International Leather Maker (page 42) covered the new bio-based materials that are being looked at for the post-tanning and finishing. This article will examine the practical use of the chemistry in today's modern process and will try to explain why these are advantageous. To remind the reader, the materials covered in that editorial article were:
- Nano-biocomposites
- Cellulose grafts
- Regenerated cellulosics
- Lignocelluloses
- Finishing cellulosics.
Since that edition of ILM in 2020, many more polysaccharides have been examined in the use of hydrogel technology, but also a look back in time shows the experience of tanners, the textbooks, leather journals and product sheets shows that saccharides have been used as monosaccharides, disaccharides or polysaccharides for a long time. Substances used include:
- Glucose for the manufacture of chromium salts
- suppression
- Dialdehyde starch
- Disaccharides in heavy vegetable manufacture (filling and grain plasticisation).
The use of dialdehyde starch was first examined in the leather industry in the 1970s. It was used by a few tanner leathers, but then seemed to fade away as other priorities in the industry started to materialise. The industry was also not prepared for the extensive post-tanning that was needed for these leathers. The perfection of the glutaraldehyde tannage would only corne through mastery of chrome-free, post-tanning that was mainly invented in the late 1990s.
Starch structure opening through oxidative ring opening allowed the starch to react, through the Maillard reaction, with the collagen. Large, bulky dialdehyde starch did not always penetrate well and many companies dropped it when they realised that the tannage may result in a raw centre.
Oxidation of saccharides that opens the compound has been modified and tweaked numerous times since the 70s. If the density of the starch opening is high the result will be a polymer that can react with the collagen in several places as the compound can bind with amine, hydroxyl and amide groups along the way. If the leather is not retanned and fatliquored correctly, the leather will be stiff and will have an unpleasant break.Note de contenu : - Biocomposites
- Hydrogels
- Lignocelluloses
- Fig. 1 : The dialdehyde starch polymer
- Fig. 2 : Carboxymethylcellulose
- Fig. 3 : Chemical structure of carrageenan
- Fig. ' : The lignin, cellulose and hemicellulose mass in plantsEn ligne : https://drive.google.com/file/d/1XKQy8bFSD2i3kqaG2C94mfBE2hMHs9b5/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37951
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Code-barres Cote Support Localisation Section Disponibilité 23483 - Périodique Bibliothèque principale Documentaires Disponible Finishing developments 2022 / Karl Flowers in INTERNATIONAL LEATHER MAKER (ILM), N° 54 (07-08/2022)
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Titre : Finishing developments 2022 Type de document : texte imprimé Auteurs : Karl Flowers, Auteur Année de publication : 2022 Article en page(s) : p. 50-52 Langues : Anglais (eng) Catégories : Biodégradation
Chimie écologique
Cuirs et peaux -- Finition
Cuirs et peaux -- Industrie -- Aspect de l'environnement
MicroplastiquesIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The development of finishes that aim to meet the performance, aesthetic and sustainability aims of the leather industry continues to take place. Chemical manufacturers are continuously looking for renewable feedstocks, and green chemistry that meets the following aims :
1. Reduce current or prevent future wastes
2. Waste few or no atoms
3. Ensure chemical manufacturing has little or no toxicity to either humans or the environment
4. Make chemical products that are fully effective yet have little or no toxicity
5. Avoid using solvents or use safer ones
6. Ensure chemistry runs at room temperatures and pressures
7. Use renewable feedstocks
8. Avoid using blocking or protecting groups that can generate waste
9. Use catalysts, e.g. enzymes or inorganic compounds
10. Make chemicals and products to degrade after use
11. Understand real-time reactions
12. Make chemicals (solid, liquid or gas) that minimise the potential for chemical accidents.
Beamhouse, tanning, post-tanning and fmishing chemistry are evaluated to meet the requirements listed above. In general, the leather industry does quite well, as many of these aims has been in development since the 1970s. In Mis article, ail 12 aims cannot be discussed with regard to fmishing developments but three of them (non-toxic chemistry, renewable feedstocks and degradable end-of-life) will be covered.Note de contenu : - Non-toxic and novel coatings
- Biobased finishes
- Biodegradability
- Microplastics
- Fig. 1 : Acrylate chemistry
- Fig. 2 : Nitrocellulose chemistry
- Fig. 3 : Polylactic acid synthesis
- Fig. 4 : The breakdown of microplasticsEn ligne : https://drive.google.com/file/d/1y9iEsAk_wpm9lOqidCA9FpYKlfJQiKz0/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37952
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Code-barres Cote Support Localisation Section Disponibilité 23483 - Périodique Bibliothèque principale Documentaires Disponible
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Titre : Carbon in soil Type de document : texte imprimé Auteurs : Abigail Clare, Auteur ; Karl Flowers, Auteur Année de publication : 2022 Article en page(s) : p. 70-72 Langues : Anglais (eng) Catégories : Atmosphère -- Pollution -- Lutte contre
Dioxyde de carbone -- Capture
Sols -- ChimieIndex. décimale : 628.5 Pollution et hygiène industrielle Résumé : Carbon is the fourth most abundant element in the universe and the 15th most abundant element on earth. Over the past 150 years, atmospheric CO2 has increased by over 30%, resulting in much research directed towards reducing atmospheric carbon levels. Soil carbon sequestration is one dominant approach to reducing atmospheric CO2.
Carbon is critical for soil function and productivity and is one of the main contributors to healthy soil conditions. Soils are a major reservoir in the global carbon cycle, with approximately 1500 Gt of organic carbon present within the top one metre of soils globally.Note de contenu : - Soils and the global carbon cycle
- Agriculture and soil carbon
- Management strategies and carbon sequestration
- Fig. 1 : Carbon sequestration in soils
- Fig. 2 : Soils make up the upper layer of the earth and can be classified as mineral or organic
- Fig. 3 : Carbon is sequestered in soils as SOM and improves soil properties
- Fig. 4 : Different types of soil management practicesEn ligne : https://drive.google.com/file/d/1aYoCVrds-NE-3KmpbVhUQc4l1ahvE4uZ/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37953
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