[article]
| Titre : |
Pigments : myth, shape and structure |
| Type de document : |
texte imprimé |
| Auteurs : |
J. R. Fryer, Auteur |
| Année de publication : |
1997 |
| Article en page(s) : |
P. 421-426 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Tags : |
'Article synthèse' 'Pigment organique' 'Interaction intermoléculaire' 'Structure cristalline' 'Mode empilement' Morphologie 'Forme 'Composé polaire' 'Relation fabrication structure' non |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
The usual textbook describes pigments in terms of the chromophore, and may give a synthetic route by which this compound can be obtained as shown for an azo pigment below.
However, in practice as is well known to those in the industry - the organic synthesis is only part of the process of making a pigment, and indeed may only be a minor part. The handling - eg rheology, the dispersibility, solubility, the colour strength, and even the shade of the pigment are function of the crystal properties.
A molecule has colour by havinf fonctional groups whose electronic transitions absorb energy in the visible spectrum. These transitions can be affected by meighbouring groups within the molecule - particulary in conjugated systems - but also by neighbouring groups in adjacent molecules which are forced into close proximity by the crystal packing. An important aspect of any molecule, which is to be considered as a pigment, is the bonding within the crystal, and how this can affect molecular proximity, and the ultimate shape of the crystal which is formed. It is necessary to consider both molecular shape, and any polar functional groups which may dominate the packing of molecules in the crystal. |
| Note de contenu : |
- TYPES OF STRUCTURE
- ORGANIC CRYSTALS
- NON-POLAR MOLECULES : Attractive.Dispersion forces - Repulsive forces
- POLAR MOLECULES : Packing of organic molecules in a crystal - Packing coefficient K
- CRYSTAL SHAPE
- CRYSTAL STRUCTURE |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17219 |
in SURFACE COATINGS INTERNATIONAL > Vol. 80, N° 9 (09/1997) . - P. 421-426
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Pigments : myth, shape and structure in SURFACE COATINGS INTERNATIONAL, Vol. 80, N° 9 (09/1997)
