Polymerization of vinyl acetate in microemulsions stabilized with a mixture of dodecyltrimethylammonium bromide and didodecyldimethylammonium bromide

Polymerization of vinyl acetate (VA) in three component oil/water (o/w) microemulsions stabilized with a mixture of two cationic surfactants (DTAB/DDAB in a weight ratio of 3), was carried out at 40, 50 and 60 degrees C using a water soluble initiator, V-50. In all cases studied, stable latexes containing particles with diameters between 70 and 110 nm were obtained. Particle size increased with conversion yielding uncommonly large particles for microemulsion polymerization, probably because particle coagulation. Multimodal molar mass distributions with average molar masses between 1.2 to 2.0x10(6) g/mol were obtained. Chain transfer to polymer and bimolecular termination reactions play important roles in the microemulsion polymerization of this monomer.