Beads mill-assisted synthesis of poly methyl methacrylate (PMMA)-TiO ₂ nanoparticle composites

A newly developed beads mill was used to create well-dispersed suspensions of TiO₂ (titania) nanoparticles in methyl methacrylate (MMA) and TiO₂-PMMA nanocomposites were synthesized by subsequent polymerization of the TiO₂-MMA suspension. Beads milling successfully broke up titania nanoparticle agglomerates with the addition of the coupling agent (3-acryloxypropyl) trimethoxysilane (APTMOS) to the titania-MMA suspension. Agglomerated particles were broken up into primary particles as small as 10 nm in suspensions with nanoparticle mass fractions as high as 0.05. Well-dispersed suspensions of titania nanoparticles had reduced UV transmission but visible light transmittance similar to pure MMA. TEM images showed that the milled nanoparticles remained well dispersed in titania-PMMA nanocomposites, and the addition of titania nanoparticles to PMMA increased the PMMA thermal stability. Spin-coated titania-PMMA films had higher refractive indices than pure PMMA films, with film of higher titania weight percent having higher refractive indices.