Polymeric nanocapsules via miniemulsion polymerization using redox initiation

The effect of using a redox initiation system (hydrogen peroxide and ascorbic acid), on the morphology of the nanoparticles formed in methyl methacrylate miniemulsion polymerization reactions with lecithin as surfactant and using high amounts of miglyol 812 or castor oil as costabilizer is compared to the use of a conventional organic phase initiator (2,2′-azo-bis-isobutironitrile). It was observed that with miglyol 812 as co-stabilizer the preferential formation of the nanocapsule morphology was achieved with both evaluated initiation systems when initiator concentrations were chosen in such a way that monomer conversions of 90% were only attained after 30 min of reaction.