High purity nanolatex prepared by ultrasonically irradiated emulsion polymerization

Ultrasonically initiated emulsion copolymerization of styrene and a cationic polymerizable surfactant (methacryloxyethyl dodecydimethyl ammonium bromide, C12N+) was successfully employed to prepare high purity copolymer nanolatex. C12N+ can play the roles of an emulsifier, an initiator, and a comonomer at the same time. It has an excellent initiation efficiency and reactivity. The rate of copolymerization was high and styrene conversion achieved 95% in an hour. Nanoscale latex particles with average diameter 40 nm were obtained easily under ultrasonic irradiation. Results of FTIR, 1H NMR and surface tension tests proved almost all surfmers had copolymerized with styrene when the C12N+ concentration was more than 0.030 g/mL, indicating high purity nanolatex without residual emulsifiers was obtained.