مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

Miniemulsions of styrene with sodium dodecyl sulphate (SOS) as the surfactant and hexadecane (HO) as the co-stabilizer were prepared and polymerized. The on-line conductivity measurements were employed to characterize the emulsification by ultrasonication. Both the dynamic light scattering (OLS) and the transmission electron microscopy (TEM) were employed to determine the droplet and the particle size. The effects of various reaction parameters on the droplet (or particle) size and the polymerization kinetics were investigated. These parameters include the sonication time and the concentrations of SOS ([SOS]), potassium persulphate ([KPS]), and HO ([HO], as weight percent with respect to monomer). Moreover, their influence on the droplet nucleation was also discussed. It is shown that a critically steady state can be obtained after ultrasonicating the emulsion system for at least 24 min and relatively stable miniemulsions were prepared. The polymerization rate of miniemulsions increases with the increase in [SOS], [HO], and [KPS] due to different mechanisms, and the rate is faster than that of the corresponding macroemulsions. In addition, the predominant droplet nucleation is achieved in current miniemulsion systems and the required condition is concluded. Finally, nanosize polystyrene latexes were synthesized.