| Autor: |
Guillaume Palaprat, François Ganachaud |
| Rok vydání: |
2003 |
| Předmět: |
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| Zdroj: |
Comptes Rendus Chimie. 6:1385-1392 |
| ISSN: |
1631-0748 |
| DOI: |
10.1016/j.crci.2003.09.002 |
| Popis: |
The preparation of PDMS microemulsions was carried out by adding at controlled rate dichlorodimethylsilane (DCMS) in a solution of sodium dodecylpolyoxyethylene(8) sulphate. The instantaneous hydrolysis of DCMS and subsequent condensation of the corresponding dihydroxysilane generate dispersions of cyclosiloxanes of small lengths (4 to 6 D units). The high load of chloride ions released during the hydrolysis step requires the presence of the above-mentioned electrosteric surfactant to avoid rapid coagulation of the dispersion. In addition, its sulphate end-group captures a proton that catalyses the ring-opening polymerization of cyclosiloxane as well as the polycondensation of disilanol PDMS chains. Final particles exhibit a diameter of about 50 nm for a polydispersity index of less than 1.1. They are constituted of PDMS chains exclusively linear ( M n,max ≈60 000 g mol -1 ; M w / M n ≈2 ) and of small cycles in low contents (less than 5 wt% in the best conditions). To cite this article: G. Palaprat, F. Ganachaud, C. R. Chimie 6 (2003). |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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