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Role of melanin and artificial hair color in preventing photo-oxidative damage to hair / Sigrid B. Ruetsch in IFSCC MAGAZINE, Vol. 7, N° 2 (04-05-06/2004)
[article]
Titre : Role of melanin and artificial hair color in preventing photo-oxidative damage to hair Type de document : document électronique Auteurs : Sigrid B. Ruetsch, Auteur ; Binhua Yang, Auteur ; Yash K. Kamath, Auteur Année de publication : 2004 Article en page(s) : p.127-135 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cheveux -- Détérioration
Cheveux -- Teinture
Colorants
Electrophorèse capillaire
Mélanine
Photo-oxydation
Photodétérioration
SpectrophotométrieIndex. décimale : 668.5 Parfums et cosmétiques Résumé : This research is a multifaceted study which investigates not only the role of melanin in providing photostability to natural hair color and hair proteins, but also the claim that the presence of specific artificial colors in hair slows down the rate of photodegradation of hair proteins. In earlier studies, the extractability of protein from photodegraded hair was investigated and showed that many of the cleaved proteins could not be extracted because of photo-oxidative cross-linking. The current study investigates the effect of the amount of melanin in hair of different ethnicity and the presence of artificial hair colors on the extractability of the main classes of hair proteins. Furthermore, the data are used in the interpretation of the effect of these components in being able to prevent photo-oxidative damage to hair proteins.
When exposed to sunlight, hair undergoes changes in chemical, mechanical and morphological properties. The UVB and UVA regions of the solar spectrum are the most damaging to human hair. Of these two, the UVA region is predominant in the solar spectrum at low altitudes. Hair of different ethnicity responds differently to the damaging radiation of the solar spectrum, because of different amounts of melanin present in hair. Melanin absorbs the impinging radiation (especially at the lower wavelengths (254–350 nm), and converts it by some complex internal mechanism into heat. Because of this, melanin provides a photochemical protection to natural hair color and hair proteins and prevents their photodegradation. However, the melanin pigments act sacrificially and become themselves degraded in the process of protecting the proteins from light. As a result, this «protective» effect of the melanin pigments does not last during long-term intense exposure, when, regardless of the amount of melanin in hair, most matrix, intermediate filament and high molecular weight hair proteins undergo photo-oxidative cross-linking into higher molecular weight species, and their extractability from hair decreases significantly.
The goal of this study is to demonstrate how UV-radiation affects natural and artificial hair color during long-term exposures. Bright-field and UV-microspectrophotometry and an electrophoretic separation technique (SDS-PAGE) were chosen as investigative techniques for these studies, because they are well-suited to accurately and reproducibly investigate the initial properties of a specific hair sample and the changes in these properties as a result of long-term light-exposure. The goal of this paper is not to relate this to the content and type of melanin in hair. Electrophoresis, while not measuring the exact quantitative amount of protein extracted, is a semi-quantitative method, where increases in brightness of the bands represent increased amounts of proteins that were extracted of that specific protein from hair. This electrophoretic study attempts to determine whether the presence of natural or artificial color in hair influences the protein extractability in unaltered hair and the photo-oxidative cross-linking during light-exposure.
The bright-field microspectrophotometric study showed that high concentrations of melanin provide protection to the melanin itself and that they prevent loss of natural hair color during light-exposure. However, neither large amounts of melanin in hair of different ethnicity, nor artificial hair colors (even a dye with an absorption in the UV region) provide protection to the hair proteins against photodegradation under the conditions used in this study.
UV-microspectrophotometry has suggested the formation of high levels of photo-oxidized proteins as a result of light-exposure. Electrophoresis revealed photo-oxidative cross-linking of most matrix, intermediate filament and high molecular weight hair proteins into their higher molecular weight analogues, rendering them less extractable due to their lowered diffusivity. Only very low levels of low molecular weight matrix proteins could be extracted.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10527
in IFSCC MAGAZINE > Vol. 7, N° 2 (04-05-06/2004) . - p.127-135[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 003883 - Périodique Bibliothèque principale Documentaires Disponible Study on photostabilization in situ of reactive hindered amine light stabilizers applied to UV-curable coatings / Yongtao Zhang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 9, N° 4 (07/2012)
[article]
Titre : Study on photostabilization in situ of reactive hindered amine light stabilizers applied to UV-curable coatings Type de document : texte imprimé Auteurs : Yongtao Zhang, Auteur ; Xiaoxun Liu, Auteur ; Zhixian Dong, Auteur ; Yanyan Cui, Auteur Année de publication : 2012 Article en page(s) : p. 459-466 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Amines Une amine est un composé organique dérivé de l'ammoniac dont certains hydrogènes ont été remplacés par un groupement carboné. Si l'un des carbones liés à l'atome d'azote fait partie d'un groupement carbonyle, la molécule appartient à la famille des amides. Découvertes en 1849, par Wurtz les amines furent initialement appelées alcaloïdes artificiels.
On parle d'amine primaire, secondaire ou tertiaire selon que l'on a un, deux ou trois hydrogènes substitués.
Par exemple, la triméthylamine est une amine tertiaire, de formule N(CH3)3.
Typiquement, les amines sont obtenues par alkylation d'amines de rang inférieur. En alkylant l'ammoniac, on obtient des amines primaires, qui peuvent être alkylées en amines secondaires puis amines tertiaires. L'alkylation de ces dernières permet d'obtenir des sels d'ammonium quaternaire.
D'autre méthodes existent : 1. Les amines primaires peuvent être obtenues par réduction d'un groupement azoture, 2. Les amines peuvent aussi être obtenues par la réduction d'un amide, à l'aide d'un hydrure, 3. L'amination réductrice permet l'obtention d'amines substituées à partir de composés carbonylés (aldéhydes ou cétones), 4. Les amines primaires peuvent être obtenues par la réaction de Gabriel.
Chimie -- Essais et réactifs
Photo-oxydation
Photodétérioration
Photostabilité
Réticulation (polymérisation)
Revêtements -- Détérioration
Revêtements -- Séchage sous rayonnement ultraviolet
Stabilisants (chimie)Index. décimale : 667.9 Revêtements et enduits Résumé : Four monomeric reactive hindered piperidinol derivatives, such as 4-methacryloyl-1,2,2,6,6-pentamethyl-piperidinyl (MPMP), 4-acryloyl-1,2,2,6,6-pentamethyl-piperidinyl (APMP), 4-methacryloyl-2,2,6,6-tetramethyl-piperidinyl (MTMP), and 4-acryloyl-2,2,6,6-tetramethyl-piperidinyl (ATMP), were applied as reactive hindered amine light stabilizers (r-HALS) in UV-curable coatings. The effect of r-HALS on the UV-curing kinetics of the UV-curable coatings of different monomers or oligomers has been previously investigated. Polymer coatings were prepared by means of UV-curing technology; experiments were conducted manually on photoaging indoors, monitoring the Yellowness Index (YI) in the photooxidation process, and adding r-HALS. The experiments were done to review its photoprotection effect on UV-cured coatings. Subsequently, they were compared with typical commercial HALS through parallel experiments to investigate the photooxidation aging mechanism of polymer coatings, and the effective concentration was determined from the changing circumstances of YI, thus comparing their differences in photostabilizing effect in situ of the polymer coatings. Note de contenu : - EXPERIMENTAL : Materials - UV-curing kinetics of the monomers/oligomers - Preparation of UV-curable coatings - Photooxidation of the coatings films
- RESULTS AND DISCUSSION : Effect of r-HALS on the UV-curing kinetics of the UV coatings - Photostabilizing efficiency of r-HALS - Comparison of photostabilizing effect between r-HALS and commercial HALSDOI : 10.1007/s11998-011-9385-3 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-011-9385-3.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16004
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 9, N° 4 (07/2012) . - p. 459-466[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 14189 - Périodique Bibliothèque principale Documentaires Disponible The enhanced cationic dyeability of ultraviolet/ozone-treated meta-aramid fabrics / Yuanyuan Dong in COLORATION TECHNOLOGY, Vol. 127, N° 3 (2011)
[article]
Titre : The enhanced cationic dyeability of ultraviolet/ozone-treated meta-aramid fabrics Type de document : texte imprimé Auteurs : Yuanyuan Dong, Auteur ; Jinho Jang, Auteur Année de publication : 2011 Article en page(s) : p. 173-178 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Colorants cationiques
Fibre aramide
Oxydation
Ozone
Photo-oxydation
Rayonnement ultraviolet
Teinture -- Fibres textiles synthétiquesIndex. décimale : 667.3 Teinture et impression des tissus Résumé : Aramid fabrics were photo-oxidised by ultraviolet/ozone irradiation. The surface properties of the modified fabrics were characterised by reflectance, attenuated total reflectance, electron spectroscopy for chemical analysis and surface zeta potential. The ultraviolet irradiation caused the oxygen content of the aramid fabric surface to increase, with the appearance of carbonyl and hydroxyl groups, and reduced the surface zeta potential, coupled with improved water wettability. Moreover, the crystalline structure did not change after ultraviolet/ozone treatment according to X-ray diffraction results. The modified aramid fabrics showed higher affinity to cationic dyes, which may have resulted from the newly introduced electrostatic interaction between cationic dyes and anionic dyeing sites on the photo-oxidised surface layers. Although colour fastness to both staining and rubbing were good to excellent, colour fastness to shade change was moderate. Furthermore, the ultraviolet/ozone pretreatment and cationic dyeing of aramid fabrics may overcome the loss in the mechanical properties associated with previously recommended dyeing methods for aramid fabrics. Note de contenu : EXPERIMENTAL : Materials and chemicals - Ultraviolet/ozone treatments - Surface characterisation - Mechanical properties - Cationic dyeing - The evaluation of dyeing
RESULTS AND DISCUSSION : Reflectance and scanning electron microscopy analysis - Wettability of aramid fabric - Surface analysis and mechanical properties - Dyeability to cationic dyesDOI : 10.1111/j.1478-4408.2011.00295.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2011.00295.x/pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12200
in COLORATION TECHNOLOGY > Vol. 127, N° 3 (2011) . - p. 173-178[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 013033 - Périodique Bibliothèque principale Documentaires Disponible The race for improved weathering / Matt Andersson in EUROPEAN COATINGS JOURNAL (ECJ), N° 1 (01/2021)
[article]
Titre : The race for improved weathering : A UV analysis technique that speeds up product development Type de document : texte imprimé Auteurs : Matt Andersson, Auteur ; Karl Booth, Auteur Année de publication : 2021 Article en page(s) : p. 40-43 Langues : Anglais (eng) Catégories : Brillance (optique)
Caractérisation
Fourier, Spectroscopie infrarouge à transformée de
Indice carbonyle
Photo-oxydation
Photodétérioration
Rayonnement ultraviolet A
Réflexion totale atténuée
Résistance aux conditions climatiques
Revêtements -- Détérioration
Revêtements organiquesIndex. décimale : 667.9 Revêtements et enduits Résumé : New product development and major reformulation of high-durability exterior coatings are among the highest risk projects a coatings lab can undertake. This is due to the years-long exterior exposure time required to validate a new product's performance, in addition to the standard formulation and test cycle time of several months. Many attributes are associated with the assessment of a coating's weatherability, such as grain-crack resistance, adhesion and chalk. In the architecture semi-gloss to high-gloss space, an emphasis has rightly been placed on gloss retention as a distinguishing attribute between high performance and economy product classes. Note de contenu : - Gloss retention today
- Gloss retention and photodegradaton
- Our improved method : ATR-FTIR characterisation
- How we did it
- Correlating carbonyl index and cyclic UVA
- Accelerating development
- Fig. 1 : ATR-FTIR characterisation
- Fig. 2 : Assignment of onset of failure by photooxidation
- Fig. 3 : Carbonyl index at one week exposure vs onset of gloss failure
- Fig. 4a : δcarbonyl index measured after 24hrs cyclic UVA exposure
- Fig. 4b : Onset of failure of gloss retentionby cyclic UVA
- Fig. 5a : Carbonyl index after seven days exposure
- Fig. 4b : Onset of failure of gloss retention by cyclic UVA
- Fig. 5b : 168 h measurement of carbonyl index predicts relative performance of commercial HG polymers
- Table 1 : Infrared absorption wavelengths for relevant functionalitiesEn ligne : https://drive.google.com/file/d/1cti9HW3V9hdCZ-CucD5b287QTa2OkXg9/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35840
in EUROPEAN COATINGS JOURNAL (ECJ) > N° 1 (01/2021) . - p. 40-43[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 22760 - Périodique Bibliothèque principale Documentaires Disponible Thermal and tensile behavior of HD-PE films containing iron (III) acetylacetonate after UV irradiation / D. Kiryakova in INTERNATIONAL POLYMER PROCESSING, Vol. XXIX, N° 5 (11/2014)
[article]
Titre : Thermal and tensile behavior of HD-PE films containing iron (III) acetylacetonate after UV irradiation Type de document : texte imprimé Auteurs : D. Kiryakova, Auteur ; S. Mihaleva, Auteur ; A. Atanassov, Auteur ; M. Tavlieva, Auteur Année de publication : 2014 Article en page(s) : p. 588-593 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acétylacétone
Chlorure de fer
Photo-oxydation
Polyéthylène haute densité
Polymères -- Propriétés mécaniques
Polymères -- Propriétés thermiques
Traction (mécanique)Index. décimale : 668.9 Polymères Résumé : The thermal, tensile and other properties of high density polyethylene films containing iron (III) acetylacetonate as pro-oxidant additive have been studied after exposure to UV irradiation for up to 300?h. The effect of photooxidation on polyethylene films with and without pro-oxidant was estimated by Fourier transform infrared spectroscopy, X-ray diffraction analysis, Differential scanning calorimeter measurements and the tensile properties. It was observed that UV irradiation had almost no effect on the melting temperature of the different samples. After exposure, the degree of crystallinity increased from 69% to 72% for the initial polyethylene samples without pro-oxidant additive and by 3% for the samples containing iron (III) acetylacetonate. It was found that the increase in the carbonyl index of initial HDPE was not significant even after 60?h exposure to UV irradiation while samples with pro-oxidant suffered substantial degradation still for 35?h. It was observed that the decrease of the tensile strength is more pronounced for the samples with pro-oxidant under irradiation for 60 to 70?h. The films containing pro-oxidant lose ?90% of its initial elongation at break after 35?h exposure. Note de contenu : - Materials
- Sample preparation
- UV exposition
- Differential Scanning Calorimeter (DSC) Measurements
- Fourier Transform Infrared Spectroscopy (FT-IR)
- X-Ray Structure Analysis
- Tensile Properties
- Melt Index
- Sol-Gel AnalysisDOI : 10.3139/217.2900 En ligne : https://drive.google.com/file/d/1bxWp7Be3YyGJfJZqFj8pJIxjlGPaE43F/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22224
in INTERNATIONAL POLYMER PROCESSING > Vol. XXIX, N° 5 (11/2014) . - p. 588-593[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 16633 - Périodique Bibliothèque principale Documentaires Disponible Utilisation de la rhéologie pour l'étude du cycle de vie des matériaux polymères / V. Verney in LES CAHIERS DE RHEOLOGIE, Vol. XVII, N° 1 (10/2000)
PermalinkUV oxidation and recovery system for tannery unhairing waste / Imogene. L. Chang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XXVII (Année 1982)
PermalinkVers un contrôle effectif des polyéthylènes additivés / Jacques Lemaire in PLASTIQUES & CAOUTCHOUCS MAGAZINE, N° 859 (07/2008)
PermalinkVieillisement des élastomères diéniques / Jacques Lemaire in CAOUTCHOUCS & PLASTIQUES, N° 771 (10/1998)
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