Magnetic polymeric microspheres based on styrene (STY) and divinylbenzene (DVB) were synthesized in two steps. Firstly, the polymeric core, constituted by STY, DVB and magnetite, was prepared by suspension polymerization. Then, the core was swollen in a STY and DVB emulsion. Subsequently, a second suspension polymerization was carried out in order to form a shell. The emulsion addition method and the swelling time were varied. The particle size, morphology, thermal stability and magnetic properties of the microspheres were studied by sieving, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). All methods tested to forming the poly(styrene-co-divinylbenzene) shell have produced particles with diameter larger than the core. This result indicates the formation of core-shell morphology. The morphologic control was only obtained with resins RR48/1 and RR48/3. Moreover, the method where the emulsion of styrene and divinylbenzene was added in one step, followed by 48 hours of core swelling at 10 °C (RR48/1), gave the highest yield (64%). All microspheres were susceptible to a magnet.
Copolymer; styrene-co-divinylbenzene; core-shell; suspension polymerization; magnetite
