Preparation of aminated polystyrene latexes by dispersion polymerization

The preparation and characterization of aminated polystyrene-based latexes as attainable by dispersion polymerization technique are reported. Mixtures of Boc-p-aminostyrene and styrene monomers at various compositions were copolymerized under dispersion conditions in 2-propanol/water 3:1 by volume in the presence of alpha,alpha'-azobis(isobutyronitrile) as free radical initiator at 75 degrees C. Copolymer microspheres with uniform size distributions and average diameters comprised between 0.9 and 1.8 mu m were obtained. Aminated microspheres were obtained by the simple removal of the Boc protective group under acidic conditions followed by neutralization, thus leading to p-aminostyrene/styrene copolymers. These chemical treatments when carried out under mild conditions (room temperature and dilute acid and basic solutions), demonstrated to be efficient without causing any major alteration of the microspheres morphology. XPS analysis of the prepared microspheres showed an increase of NH2 groups with the increasing of the Boc-p-aminostyrene in the copolymer feed up to 10 mol %.