Synthesis of polydimethylsiloxane microemulsions by self-catalyzed hydrolysis/condensation of dichlorodimethylsilane

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