[article]
| Titre : |
Comparing hair tensile testing in the wet and the dry state : Possibilities and limitations for detecting changes of hair properties due to chemical and physical treatments |
| Type de document : |
document électronique |
| Auteurs : |
Franz J. Wortmann, Auteur ; Jutta M. Quadflieg, Auteur ; Gabriele Wortmann, Auteur |
| Année de publication : |
2022 |
| Article en page(s) : |
p. 421-430 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Analyse de variance En statistique, l'analyse de la variance (terme souvent abrégé par le terme anglais ANOVA : ANalysis Of VAriance) est un ensemble de modèles statistiques utilisés pour vérifier si les moyennes des groupes proviennent d'une même population. Les groupes correspondent aux modalités d'une variable qualitative (p. ex. variable : traitement; modalités : programme d'entrainement sportif, suppléments alimentaires ; placebo) et les moyennes sont calculés à partir d'une variable continue (p. ex. gain musculaire).
Ce test s'applique lorsque l'on mesure une ou plusieurs variables explicatives catégorielles (appelées alors facteurs de variabilité, leurs différentes modalités étant parfois appelées "niveaux") qui ont de l'influence sur la loi d'une variable continue à expliquer. On parle d'analyse à un facteur lorsque l'analyse porte sur un modèle décrit par un seul facteur de variabilité, d'analyse à deux facteurs ou d'analyse multifactorielle sinon. (Wikipedia)
Cheveux -- analyse
Cheveux décolorés
Cheveux humides
Cheveux secs
Essais dynamiques
Justification de l'allégation
Statistique
Traction (mécanique)
Traitement thermique
|
| Index. décimale : |
668.5 Parfums et cosmétiques |
| Résumé : |
- Objectives : This investigation focuses, first, on the question to which extent wet and dry tensile tests on human hair may be considered as leading to independent results. Second, we try to assess the sensitivities of wet and dry-testing to detect changes of mechanical properties. Specifically, we were interested in separating changes, which were induced by a combination of a chemical (oxidation/bleach) and a physical treatment (heat).
- Methods : The basis for our study are data for the tensile properties (wet and dry) of a set of untreated and bleached hair tresses, which were submitted to the same schedule of thermal treatments. As characteristic tensile parameters, we chose modulus (E), break extension (BE), and break stress (BS). First, parameters were analysed across treatments for the correlations between wet and dry data. Second, we applied two-factor analysis of variance to assess the effects of the factors and their potential interaction.
- Results : Correlations for the dry versus wet data show only a weak relationship for E, while coefficients of determination (R2) are quite high for BE and BS. Two-factor ANOVA enables to quantify the various contributions to the Total Sum-of-Squares for all three parameters. We show that the parameters respond quite differently to the chemical and the thermal treatments as well as to testing conditions (wet or dry). It is of interest to note that the interaction between the chemical and the physical treatment is generally quite weak. For the interpretation of the results, we use the concept of the humidity-dependent as well as strain-induced glass transition of the amorphous matrix.
- Conclusions : The independence hypothesis for dry and wet tensile measurements only applies for modulus. Overall, we consider modulus (wet) as the best tensile measure of fibre damage when assessing chemical and/or physical treatments. Under ambient conditions (dry), break stress is shown to be a feasible alternative measure. |
| Note de contenu : |
- EXPERIMENTAL : Materials and methods - Choice of variables, basic data, and statistical analysis - Correlations wet vs dry - 2-Factor ANOVA
- DISCUSSION : The independence hypothesis - Two-Factor ANOVA
- Table 1 : Summary of basic statistics for the investigated variables for natural/chemically untreated (N) and bleached (B) hair
- Table 2 : Parameter values of the regression equations, when plotting variable means (n = 8) for dry vs wet testing
- Table 3 : Summary of the various sum-of-squares (SS) components for the three chosen variables (wet and dry), according to Equations |
| DOI : |
https://doi.org/10.1111/ics.12796 |
| En ligne : |
https://drive.google.com/file/d/1lf_6im_y7ozRCbt5z_EPSBMWt4BrXRLh/view?usp=shari [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38142 |
in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 44, N° 4 (08/2022) . - p. 421-430
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Comparing hair tensile testing in the wet and the dry state : Possibilities and limitations for detecting changes of hair properties due to chemical and physical treatments in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 44, N° 4 (08/2022)
