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Biosynthesis and synthesis of natural colours / Timothy L. Dawson in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 61-73 Titre : Biosynthesis and synthesis of natural colours Type de document : texte imprimé Auteurs : Timothy L. Dawson, Auteur Année de publication : 2009 Article en page(s) : p. 61-73 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : In nature, the detection of colours requires an organism having some type of eye with a retina and two or three types of photoreceptor connected to a nervous system, which can interpret the signals received. Evidence that certain simple organisms were coloured 1 billion years ago, and some more advanced creatures, which could have possessed eyes a few hundreds of million years ago, is exemplified. A vast array of chemicals essential to life are produced by living organisms and their biosynthesis depends upon individual genetic patterns, which determine the enzyme catalysts involved. Plants photosynthesise many pigments, which are essential for them to maximise the absorption of energy from the sun, while others offer protection from any harmful radiation. Such pigments, for example chlorophylls and the carotenoids, flavonoids and betalains, have traditionally been used as natural dyes, food colorants and medicines. This review compares the chemical processes involved in their biosynthesis and the laboratory methods adopted to confirm their chemical structure. Some engineered biosynthetic methods are now used for commercial production of natural colours and these methods may involve the controversial use of genetic engineering. DOI : 10.1111/j.1478-4408.2009.00177.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00177.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4851 [article]

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Use of regression methods for determining the relation between theoretical–linear and spectrophotometrical colour values of bicolour woven structures / Helena Gabrijelcic in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 74-85 Titre : Use of regression methods for determining the relation between theoretical–linear and spectrophotometrical colour values of bicolour woven structures Type de document : texte imprimé Auteurs : Helena Gabrijelcic, Auteur ; Krste Dimitrovski, Auteur Année de publication : 2009 Article en page(s) : p. 74-85 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : In this paper, new approaches for evaluating the entire colour effect of optical mixing of bicolour woven structures are presented. Simple woven structures with constant colour in the warp direction and different colours in the weft direction were prepared and analysed. The constructional parameters of these woven fabrics were systematically changed, which resulted in the variations of the fractions of colour components and, consequently, also in the changes of colour properties (lightness, hue, chroma) of bicolour optical mixtures. The position of colours of the bicolour structures and the approximate direction (linear) of colour changes in CIELAB colour space were theoretically determined with a simple geometrical model and additive method. Furthermore, the bicolour optical effects were determined spectrophotometrically. The differences between the linear–theoretical and the spectrophotometrical colour values of bicolour woven fabrics were mathematically analysed with linear and non-linear regression methods to determine the positions of colour coordinates L*, a* and b* of bicolour woven fabrics in the a*b* plane by increasing or reducing the cover factors of warp and weft threads (addition or reduction of colour components). The results present, on the one hand, the strong influence of original colours of warp and weft threads and, on the other hand, the minor influence of constructional parameters on the form of linear/non-linear behaviour of colours of bicolour compositions. When the characteristics of a specific colour combination are taken into account, the spectrophotometrical colour values of bicolour woven fabrics can be also mathematically determined with additive–theoretical colour values and, to some extent, with predictable colour deviations. DOI : 10.1111/j.1478-4408.2009.00178.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00178.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4852 [article]

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Photofading of phenylazo-aniline, -pyridone and -quinolone disperse dyes on a nylon 6 substrate / Yasuyo Okada in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 86-98 Titre : Photofading of phenylazo-aniline, -pyridone and -quinolone disperse dyes on a nylon 6 substrate Type de document : texte imprimé Auteurs : Yasuyo Okada, Auteur ; Zenzo Morita, Auteur ; Toshio Hihara, Auteur Année de publication : 2009 Article en page(s) : p. 86-98 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : The photofading of phenylazo-aniline, -pyridone and -quinolone disperse dyes on nylon fabric was analysed using the Kubelka–Munk (K/S) spectra of fabrics exposed to a carbon arc in air. The exposure of dyed fabric through ultraviolet and coloured filters, which do not shield the main absorption band, showed a large decrease in the initial rate (KPA) of fading. Compared with the KPA values without filters, the values using filters were half as large for dyes without the nitro groups and a quarter as large for dyes with the nitro groups. The KPA values may be qualitatively explained by the sum of azo scission (decrease of K/S value at lambda max) and the conversion of nitro groups to nitroso groups. These phenomena occur, respectively, via thermal disproportionation reactions between hydrazinyl radicals (from the azo group) and the reaction between hydrazinyl and N-centred nitrosyl hydroxide radicals (from the nitro group). The azo scission is promoted by N-centred nitrosyl hydroxide radicals via the latter reactions. DOI : 10.1111/j.1478-4408.2009.00179.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00179.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4853 [article]

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Analysis of the wetting behaviour of pigments and the effectiveness of surfactants / Amit Joshi in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 99-103 Titre : Analysis of the wetting behaviour of pigments and the effectiveness of surfactants Type de document : texte imprimé Auteurs : Amit Joshi, Auteur ; Sahas Rathi, Auteur ; Suhas Deshpande, Auteur Année de publication : 2009 Article en page(s) : p. 99-103 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : A new test method is introduced to analyse the wetting behaviour of pigments and the effectiveness of surfactants. The method involves the study of torque vs time curves obtained during the wetting of pigments by surfactant solutions. These curves provide valuable information regarding the wetting behaviour of pigments and the ability of the surfactant to wet the pigment. To study the wetting behaviour, two pigments which varied widely in their surface character are studied with the same surfactant, while, to study the effectiveness of the surfactant, different surfactants with differing polarity are studied using the same pigment. The results are found to be consistent with the theoretical expectations. DOI : 10.1111/j.1478-4408.2009.00180.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00180.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4854 [article]

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Synthesis, absorption spectra studies, solvatochromism and halochromism of polymethine cyanine dyes / Hassan Abazied Shindy in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 104-110 Titre : Synthesis, absorption spectra studies, solvatochromism and halochromism of polymethine cyanine dyes Type de document : texte imprimé Auteurs : Hassan Abazied Shindy, Auteur ; M. A. El-Maghraby, Auteur ; Fayez M. Eissa, Auteur Année de publication : 2009 Article en page(s) : p. 104-110 Note générale : Corrigendum in vol. 125, N° 3, p. 191 - Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : New polymethine cyanine dyes, including tetramethine and bis-tetramethine cyanine dyes derived from benzo[2,3-b;2',3'-b']bis-pyrazolo[4,5-b]-1,4-(oxa-, thia- and pyra-)-zine-6,12-dione, were synthesised. Absorption spectra for all the synthesised cyanine dyes were examined in 95% ethanol. The solvatochromism and halochromism for some selected dyes were investigated in pure solvents and in aqueous universal buffer solutions, respectively. Structural confirmations were carried out through elemental and spectroscopic analysis. DOI : 10.1111/j.1478-4408.2009.00181.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00181.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4855 [article]

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Absorption of nanoparticles by wool / David G. King in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 111-116 Titre : Absorption of nanoparticles by wool Type de document : texte imprimé Auteurs : David G. King, Auteur ; Anthony P. Pierlot, Auteur Année de publication : 2009 Article en page(s) : p. 111-116 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : Wool was treated with inorganic and polymer-based nanoparticles. The diffusion of nanoparticles into wool appears to be dependent on electrostatic interactions. In particular, it is optimised at low pH in which there are very few anionic groups on the wool fibre; the nanoparticles also need to have sufficient charge to maintain their stability as dispersion. The findings support the view that the cell membrane complex and other low sulphur regions are the main route of entry for both molecular and macromolecular treatment chemicals. The use of this technique to treat wool may lead to new coloration effects and other functions such as antimicrobial action. DOI : 10.1111/j.1478-4408.2009.00182.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00182.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4856 [article]

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Mechanism of photoprotection of wool with formaldehyde and thiol derivatives / Keith R. Millington in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 117-122 Titre : Mechanism of photoprotection of wool with formaldehyde and thiol derivatives Type de document : texte imprimé Auteurs : Keith R. Millington, Auteur ; George Maurdev, Auteur ; Michael J. Jones, Auteur Année de publication : 2009 Article en page(s) : p. 117-122 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : The application of thiourea and formaldehyde offers significant reductions in photoyellowing for natural, bleached and fluorescent-brightened wools. We have examined the use of alternative thiol derivates to thiourea and shown that a mixture of N-acetylcysteine and formaldehyde is similarly effective. Photo-induced chemiluminescence studies on treated wool fabrics show that the intensity of chemiluminescence following a brief exposure to ultraviolet A radiation is reduced for wool treated with thiourea and formaldehyde, N-acetylcysteine–formaldehyde and thiourea dioxide–formaldehyde, but not for formaldehyde alone. This demonstrates that a lower population of free radicals is formed in irradiated thiol-derivative formaldehyde-treated wools because of free radical scavenging by the sulphur-containing species. This free radical scavenging results in reduced photoyellowing. The effect of thiourea and formaldehyde treatment on the intrinsic fluorescence of wool is significantly different to N-acetylcysteine–formaldehyde. Thiourea and formaldehyde quenches tryptophan fluorescence relative to untreated wool, whereas N-acetylcysteine–formaldehyde treatment results in an increase in intensity probably because of a reduction in disulphide quenching. DOI : 10.1111/j.1478-4408.2009.00183.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00183.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4857 [article]

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Protection of lyocell fibres against fibrillation ; mechanism for the poor crosslinking performance of reactive dyes on lyocell fibres and the influence of a colourless crosslinking agent as co-applicant / R. Ibbett in COLORATION TECHNOLOGY, Vol. 125, N° 2 (2009)  

[article]  inCOLORATION TECHNOLOGY > Vol. 125, N° 2 (2009) . - p. 123-131 Titre : Protection of lyocell fibres against fibrillation ; mechanism for the poor crosslinking performance of reactive dyes on lyocell fibres and the influence of a colourless crosslinking agent as co-applicant Type de document : texte imprimé Auteurs : R. Ibbett, Auteur ; H. Owens, Auteur ; R. Reisel, Auteur ; A. H. M. Renfrew, Auteur Année de publication : 2009 Article en page(s) : p. 123-131 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : Sandospace R and five multi-functional reactive dyes have been applied to lyocell fibre, by exhaust methods. A comparison has been made of the number of mmoles of each species covalently bonded to the fibre, with cross-linking efficiency (NSF values). None of the dyes studied was able to achieve levels of cross-linking found in non-fibrillating grades of lyocell, unless unrealistically high levels were applied. Sandospace R readily matched the NSF values found in commercially produced non-fibrillating fibres. An explanatory mechanism based on differences in size between Sandospace R and the reactive dyes has been proposed. Fitting the experimental NSF data to an Arrhenius model confirmed the increasing gradient of the NSF curves with increasing millimolar concentration of species fixed. The chroma of the agent-plus-dye fibre samples remained relatively constant being either at the same level or above that of those fibre samples treated only with dye. Co-application of Sandospace R with the reactive dyes has achieved levels of cross-linking found in commercial non-fibrillating lyocell fibres. DOI : 10.1111/j.1478-4408.2009.00184.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2009.00184.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4858 [article]

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