A method for determining the content of cyclosiloxanes in silicone emulsion by gas choromatography was established. The rates of diffusion and polymerization of hexa-methylcyclotrisiloxane (D3)

octamethylcyclotetra-siloxane (D4) and decamethylcyclopen-tasiloxane (D5) in the presence of dodecyldimethylbenzylammonium bromide were investigated. As the amount of polymer produced increases

D4 increases accordingly in the water layer. It can be assumed that the OH-ended polydimethylsiloxane may serve as a sort of co-emulsifier.