Search

In this work, the Pickering emulsion polymerization of styrene (STY) with silica nanoparticles as stabilizers and ammonium persulfate (APS) as initiator, was studied. The effects of several co-aids, considered as modifying agents to vary the compatibility of colloidal silica (Ludox AM) between the polymer interface during the emulsion polymerization, are evaluated. Sodium vinyl benzene sulfonate, 4-vinyl pyridine, poly(ethylene glycol) methyl ether methacrylate (PEGMA), and cetyltrimethylammonium bromide (CTAB) surfactant, are appraised. The obtained emulsions range from bare, hybrid encapsulated and Pickering nanoparticles. The obtained Pickering emulsion formulation requires smaller amounts of co-aids, as compared to the reported recipes from the literature. [ABSTRACT FROM AUTHOR]

In this work, polymerizations of styrene (St) in the presence of divinylbenzene (DVB) as a crosslinking agent and sodium 4-vinylbenzenesulfonate (VBS) have been performed in Pickering emulsions, using silica nanoparticles (SNps) as stabilizing agents and ammonium persulfate as a hydrophilic initiator. In oil-in-water Pickering emulsions with alkaline continuous phase (pH = 9) at 1, 2, and 3 wt% DVB (relative to St), polydisperse spheroid copolymer submicronic nanoparticles were obtained. Comparatively, polymerizations performed in Pickering emulsions with acidic continuous phase (pH = 5) allowed preparing St-co-DVB microspheres with core–shell structures at 1 wt% DVB and St-co-DVB hybrid monoliths with bi-continuous morphologies at 2 and 3 wt% DVB. It is noteworthy that this work reports Pickering emulsion polymerization as a new strategy for preparing hybrid percolated scaffolds with bi-continuous porosity. The proposed mechanisms originated by pH, DVB, and VBS and the drastic impact caused on the final morphology obtained, either hybrid particles or monoliths, are discussed herein. [ABSTRACT FROM AUTHOR]