Coton

Résumé

vignette|Coton, préparé pour une récolte mécanisée par un défanage chimique (généralement par du méthanearséniate monosodique, qui est une source durable et croissante de pollution des champs de coton par l'arsenic. vignette|Machine à récolter le coton, qui a remplacé le travail fastidieux de millions d'ouvriers agricoles. vignette|Récolte du coton au Pérou en 2003. Le coton est une fibre végétale qui entoure les graines des cotonniers « véritables » (Gossypium sp.), arbustes de la famille des Malvacées. Cette fibre, constituée de cellulose presque pure, est généralement transformée en fil qui est tissé pour fabriquer des tissus. Le coton est la fibre naturelle la plus produite dans le monde, principalement en Chine et en Inde. Depuis le , il constitue, grâce aux progrès de l'industrialisation et de l'agronomie, la première fibre textile du monde (près de la moitié de la consommation mondiale de fibres textiles). Botanique Plante Herbacé ou ligneux, le cotonnier

Source officielle

https://fr.wikipedia.org/wiki/Coton

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (9)

Chargement

Afficher plus

Publications associées

Chargement

Personnes associées (3)

Personnes associées

Chargement

Unités associées (3)

Unités associées

Chargement

Concepts associés (106)

Concepts associés

Chargement

Cours associés (5)

Cours associés

Chargement

Séances de cours associées (5)

Afficher plus

Séances de cours associées

Chargement

Publications associées (9)

Innovative High-Surface-Area CuO Pretreated Cotton Effective in Bacterial Inactivation under Visible Light

Paul Bowen, Juan Kiwi, Victor Sarria

This study presents the first report on enhanced bacterial inactivation of E. coli by RF-plasma pretreated cotton with high-surface-area CuO powders compared with nonpretreated cotton textiles. The high-surface-area CuO (65 m/g) powder was fully characterized. The E. coli inactivation proceeded in the dark and was accelerated under visible and sunlight irradiation even at very low levels of visible light irradiation. The effect the RF-plasma pretreatment of the cotton on the binding of CuO, applied light dose, the amount of CuO loading and initial E. coli concentration on the inactivation kinetics of E. coli is reported in detail.

2010

Chargement

Self-cleaning modified TiO2-cotton pretreated by UVC-light (185 nm) and RF-plasma in vacuum and also under atmospheric pressure

Juan Kiwi, César Pulgarin

Two new innovative findings presented in this study are: (a) TiO2-cotton fabrics obtained by pretreatment with UVC-light (185nm) at atmospheric pressure introduced functionalities into the cotton surface enabling the chelation/binding of TiO2. This was possible since the molar absorption coefficient of O-2 and N-2 is very low at 185 nm and (b) the radiofrequency (RF-plasma) pretreatment of cotton surface lead to the formation active binding sites on the cotton at atmospheric pressure. This unexpected RF effect was due to the drastic localized heating of the cotton leading to intermolecular H-bond breaking between the cellulose surface-OH groups of adjacent molecules with the formation of functionalized groups in the cellulose fibers. The discoloration kinetics of the wine stain on the TiO2-cotton pretreated by RF at atmospheric pressure for 10 min was the most favorable. The red wine stains discoloration under Suntest simulated light was monitored by diffuse reflectance spectroscopy (DRS) and by the CO2 evolution during the stain mineralization. By X-ray photoelectron spectroscopy (XPS) it was possible to monitor the decrease of the C, N, S-species on the textile topmost layers during the discoloration process. The XPS Ti 2p(3/2) peak shifts indicating Ti4+/Ti3+ oxido-reduction taking place during the photocatalysis. X-ray diffraction showed the formation of the anatase phase on the cotton. By X-ray fluorescence the loading of TiO2 before and after the discoloration process was found to be similar to 0.8%. High-resolution electron microscopy (HRTEM) shows transparent TiO2 anatase 8-18 nm coating the cotton with layers similar to 31 nm (+/- 10%). These 3-4 TiO2 layers on the cotton did not affect the touch or handling properties of the cotton enabling the potential commercial use of the TiO2-cotton fabrics. (C) 2009 Elsevier B.V. All rights reserved.

2009

Chargement

To prepare bactericide textiles, TiO2 has been added in the form of colloid, powder or a combination of both and the TiO2 modified textiles subsequently cured at temperatures adapted to their specific heat resistance. The bactericide textile is activated and Ag is deposited on the activated cotton or polyester to induce oxygen functionalities containing diverse polar groups. These polar groups increase the bondability of TiO2 and Ag with the textile surface. These functionalities generated in the presence of O-2 by RF-plasma (Radio-frequency plasma) and Vacuum-UV led to an increased adhesion of the TiO2 and Ag on the textiles. Recent findings comprising surface chemistry, photochemistry and microbiology of the bactericide textiles are presented in detail. (C) 2010 Elsevier B.V. All rights reserved.

2010

Chargement

Afficher plus

Self-cleaning modified TiO2-cotton pretreated by UVC-light (185 nm) and RF-plasma in vacuum and also under atmospheric pressure

Juan Kiwi, César Pulgarin

2009