STYRENE AND METHYLMETHACRYLATE OIL-IN-WATER MICROEMULSIONS

A simple procedure for the preparation of styrene-in-water and methylm ethacrylate (o/w) microemulsions was established. This consisted of th e preparation of a w/o emulsion using a low HLB number surfactant (Syn peronic NP4, nonyl phenyl with 4 mol ethylene oxide) and a small amoun t of an anionic surfactant (Aerosol OT, diethyl hexyl sulphosuccinate, or sodium dodecyl benzene sulphonate). The w/o emulsion was then titr ated with an aqueous solution of a high HLB number surfactant (Synpero nic NP15 nonyl phenyl with 15 mol ethylene oxide). The droplet size an d polydispersity were determined using photon correlation spectroscopy (PCS). The temperature range within which a microemulsion remained st able decreased with increase in the concentration of styrene or methyl methacrylate and this could be explained in terms of the phase diagram of the microemulsion system. Conductivity measurements as a function of temperature showed that the systems are oil-in-water microemulsions .