[article]
| Titre : |
Organo-functional silicones – choices for formulations |
| Type de document : |
texte imprimé |
| Auteurs : |
Kevin O'Lenick, Auteur ; Tony O'Lenick, Auteur |
| Année de publication : |
2008 |
| Article en page(s) : |
p. 27-30 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Ingrédients cosmétiques
Matériaux -- Propriétés fonctionnelles
SiliconesLes silicones, ou polysiloxanes, sont des composés inorganiques formés d'une chaine silicium-oxygène (...-Si-O-Si-O-Si-O-...) sur laquelle des groupes se fixent, sur les atomes de silicium. Certains groupes organiques peuvent être utilisés pour relier entre elles plusieurs de ces chaines (...-Si-O-...). Le type le plus courant est le poly(diméthylsiloxane) linéaire ou PDMS. Le second groupe en importance de matériaux en silicone est celui des résines de silicone, formées par des oligosiloxanes ramifiés ou en forme de cage (wiki).
|
| Index. décimale : |
668.5 Parfums et cosmétiques |
| Résumé : |
A question asked by every formulator is: “How do I get the highly desirable properties of silicone in my formulation when formulating with silicone can provide its own set of problems? In short this is what we define as “The Silicone Conundrum”, an intricate and difficult problem. The selection of the proper silicone for a formulation requires the formulator to understand why the silicone is in the formula (for wetting, conditioning, emulsification, skin feel, film formation...) and which silicone provides that property most efficiently in the formula (with all the other ingredients). First and foremost, one must understand the chemistry of silicone polymers and the effect of structure on function.
Silicone compounds have been known since the 1860s, but it was not until the pioneering of Rochow in the 1940s that
this important class of compounds achieved commercial viability. This was due in large part to the development of a
process which was called the direct process, and now bears Rochow’s name. Silicone chemistry provides the polymer
chemist with the ability to construct precise molecules having desirable nanotechnology properties. Silicone polymers are derived from SiO2, a naturally occurring mineral that makes up 25% of the earth’s crust. SiO2 is converted
to Si at high temperature in the presence of a carbon source. Figure 1 shows the two materials. The resulting Si metal is then crushed and reacted in a fluidised bed reactor to
produce chlorosilanes, using the Rochow process. The reaction is shown in Figure 2. The preparation of chlorosilanes is
practised by a small number of manufacturers who grind up silicon metal and react it in a tubular reactor with methyl
chloride. The manufacturers of chlorosilanes are affectionately referred to as “crushers”. Chlorosilanes are hydrolysed in water to make intermediates used to make silicone derivatives. The reaction product of water and chlorosilanes is referred to as hydrolysate. The chlorosilanes are placed into water, HCl stripped off and after distillation and a variety of clean-up processes, a series of silicone building blocks emerge. The most important of these includehexamethyldisloxane (MM), cyclomethicone
(D4) and silanic hydrogen compound.That is just the start of the story.These materials are combined in a variety of ways to make silicone polymers of interest. The unit operations are shown in Figure 3. |
| Note de contenu : |
- Construction : Silicone fluids - dimethicone
- Functionalisation : 1. Dimethicone copolyol compounds - improved water solubility - 2. Alkyl dimethicone - improved oil solubility |
| En ligne : |
https://drive.google.com/file/d/1PVjwADU_KyIF5gQuXMZkOA8luTZLGDKp/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22088 |
in PERSONAL CARE EUROPE > Vol. 1, N° 1 (09/2008) . - p. 27-30
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Organo-functional silicones – choices for formulations in PERSONAL CARE EUROPE, Vol. 1, N° 1 (09/2008)
