Effect of Fe3O4 particles on multi-hollow morphology of poly(HEMA-divinylbenzene-styrene) microspheres prepared by Pickering suspension polymerization

Hydroxy-functionalized polymers have been synthesized by Pickering suspension polymerization of 2-hydroxyethyl methacrylate (HEMA) with styrene (S) and divinylbenzene (DVB) in the presence of hydrophobic Fe 3 O 4 particles.The obtained polymer microspheres were characterized using different instrumental techniques (optical microscopy, scaning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), diffuse reflection ultraviolet-visible spectroscopy (DR UV-Vis), inductively coupled plasma-optical emission spectrometry (ICP-OES), dynamic light scattering and thermal analyses) and then modified to immobilize the complexes of palladium(II) with the tetradentate ligands based on salicylaldehyde, epichlorohydrin and 2-picolylamine.The resulting polymer supported complexes were preliminarily examined as catalysts in the model Suzuki reaction between 4-bromotoluene and phenylboronic acid.It was found the polymer particles obtained as a result of the performed polymerization have composite nature and are characterized by a unique multi-hollow morphology with pores up to 50 μm in size.An advantageous effect of the Fe 3 O 4 particles embedded in the synthesized polymer microspheres on the activity of palladium catalysts has been noted.