Abstract
A partially hydrophilic crosslinked silicone was synthesized by the addition polymerization of a methylhydrogenpolysiloxane and a polyoxyethylene diallylether. The crosslinked silicone obtained can swell in dimethylpolysiloxane (silicone oil) forming a gel, and a large amount of water can also be successfully taken into the gel to form a stable W/O type emulsion. The W/O emulsion prepared using the synthesized crosslinked silicone was confirmed to have larger water droplets, and to contain a larger amount of water when compared with the emulsion prepared by the conventional silicone type W/O emulsifier (polyoxyethylene·methylpolysiloxane copolymer). The larger water droplets of the emulsion is well understood by the fact that the synthesized crosslinked silicone consists of dispersed particles with practically no soluble components, therefore has a lower ability of decreasing the interfacial tension between water and dimethylpolysiloxane (silicone oil). The stability of the emulsion in spite of its large water droplets is supposed by the following facts: 1) The interfacial film can be effectively formed by the dispersed crosslinking silicone which orientates between water and dimethylpolysiloxane (silicone oil), because of its hydrophilic and hydrophobic moiety. 2) The crosslinked silicone entangles its polysiloxane chains in dimethylpolysiloxane-the outer phase of the emulsion, forming the network. Therefore the dimethylpolysiloxane (silicone oil) existing around the water loses its fluidity and stays in a gelling state. And the viscosity of the gel shows little temperature-dependence because of its polysiloxane chain structure. Hence, the water, the inner phase of the emulsion, will not coagulate and the emulsion is stable in a wide temperature range.
