Microemulsion vs. macroemulsion polymerization of octamethylcyclotetrasiloxane: A preliminary kinetic study

Octamethylcyclotetrasiloxane (D4) was polymerized to prepare microemulsion PDMS latexes via developed formulation using acrylamide a co-emulsifier. Dodecylbenzene sulfonic acid was used as both cationic initiator and emulsifier. A conventional (macroemulsion) system was also studied comparatively. Rp in microemulsion was increased quickly to a maximum of 0.108 mol L-1s-1 at ~30 min corresponding to a conversion of ~38%, and then decreased with reaction progression in period of 30–110 min. In macroemulsion system, however, a constant rate was observed between conversion 30 and 50%, and its optimal sample contained an average particle diameter of 88 nm while that from microemulsion had much smaller particles with diameter of 19 nm