Polydimethylsiloxane emulsions are widely used in coatings

personal care products

because of their low toxicity

high chain flexibility and low surface energy.It has various good properties

such as thermal stability

low temperature performance and lubricity.It has been applied to different areas of industry.A polydimethylsiloxane miniemulsion was prepared with sodium dodecylbenzene sulfonate (SDBS) as emulsifier

sulfuric acid or hydrochloric acid as catalyst

octamethylcyclotertrasiloxane (D4 as monomer

hexadecane (HD) as costabilizer and ultrasonication as preemulsification method.By reducing the monomer droplet size using pre_emulsifying method

and using hydrophobic substance as costabilizer to retard monomer transfer in aqueous phase

the monomer droplets become independent mini_reactors in miniemulsions.The effects of ultrasonic time

amount of catalyst and emulsifier

and temperature on kinetics of miniemulsion polymerization were investigated.Short ultrasonication time is not sufficient for obtaining the stable miniemulsion and high conversion of D