silicone emulsion

[qacampby]

What can be done to keep dimethylpolysiloxane in a dispersed phase when using an emulsifying agent such hexane, xylene or hydrofluoroether azeotrope?
We are currently investigating the use of these agents to coat syringe needles with the dimethylpolysiloxane. Ronald G. Campbell
Quality Assurance Manager
Shinamerica, Inc.

 

[kiranreddy]

There are some proprietary products(surfactants) which can be used for stabilizing dimethylpolysiloxane. Most of them have patents. There are some commercial ones available.
Check this site out for some examples.

http://www.masterchemical.com/3/3eframe-3.html

TRIM (r) TC 143 is a potential candidate.

Remember in an azeotropic system, the stability of the emulsion becomes a complex function of the azeotropic composition and solids composition. Usually for polysiloxanes you will have to use more than one stabilizer (surfactants) with different molecular weights and poly dispersities.

However since your application is for medical purposes, getting FDA approval for complex azeotropic systems might be a problem. But since you already have xylene and hexane as your components, the additional surfactants shouldn’t be a major issue. More over some proprietary emulsion stabilizers are proven biocompatible.
Hope this information helps.

Sincerely,
Kiran Reddy