Preparation of uniform titanium dioxide (TiO_2) polystyrene-based composite particls using the glass membrane emulsification process with a subsequent suspension polymerization

摘要

Uniform titanium dioxide (TiO_2)-polystyrene-based composite particles were prepared using the glass membrane emulsification process followed by a subsequent suspension polymerization The oil phase, consisting of anatase TiO_2 fine powder, monomers, methyl laurate as the hydrophobic additive, Dispebyk-180 and the poly(styrene-co-2-ethyl hexylacrylate) were emulsified through the membrane pores into the aqueous phase containing stabilizers to form a (solid-in-oil)-in-water (S/O/W) emulsion of monomer droplets. The suspension polymerization was carried out at 343 K for 24 h under a nitrogen atmosphere. An SPG membrane with a pore size of 5.25 #mu#m was employed and 20-25 #mu#m TiO_2-polystyrene based composite particles were obtained depending on the composition of polymerizing oil phase. The effects of the co-monomer, 2-ethylhexyl acryalte and the cross-linking agent, divinyl benzene on the dispersion stability of TiO_2 in the oil phase, the surface feature of the particle and the encapsulation loading were investigated in this study. The membrane emulsification process was capable of preparing the composite particles with approx5 wt% of TiO_2 encapsulated, which accounts for with at least 85 wt% of TiO_2 in the oil phase.