Preparation of uniform titanium dioxide (TiO₂) polystyrene-based composite particles using the glass membrane emulsification process with a subsequent suspension polymerization

Abstract

Uniform titanium dioxide (TiO₂)-polystyrene-based composite particles were prepared using the glass membrane emulsification process followed by a subsequent suspension polymerization. The oil phase, consisting of anatase TiO₂ fine powder, monomers, methyl laurate as the hydrophobic additive, Disperbyk-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 μm was employed and 20–25 μm TiO₂-polystyrene based composite particles were obtained depending on the composition of polymerizing oil phase. The effects of the co-monomer, 2-ethylhexyl acrylate and the cross-linking agent, divinyl benzene on the dispersion stability of TiO₂ 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 ∼ 5 wt% of TiO₂ encapsulated, which accounts for with at least 85 wt% of TiO₂ in the oil phase.

Key Words:

• Titanium dioxide
• polystyrene copolymer
• photo-oxidation catalyst
• suspension polymerization
• microcasule
• microparticle