(132e) Converting Processes to Unfold the Potential of Nanoparticles

The huge innovation potential in connection with nanoparticles (d < 100 nm) as nano-additives, e.g., in coatings, plastics and product formulations in general, can in most cases only be utilized, if an excellent state of dispersion is accomplished. Agglomerated or even aggregated nanoparticles are widely available on the market, but do seldom provide advantages in comparison to well-known micro- and sub-micron sized additives. To produce usable nanoparticle dispersions, we propose a new technique of nanoparticle processing in agitator bead mills comprising the concurrent utilization of chemical and mechanical action called chemomechanical processing. Agitator bead mills provide a number of advantages in the processing of nanoparticles. Most notably, the milling chamber can be understood as a reaction vessel where complex chemical reactions can be conducted under well-defined mechanical conditions in the wet phase. The talk will discuss the effect of the surface reactivity of the starting material, the influence of the size, type and quantity of surfactants used, the diffusion and reaction kinetics in the processing chamber, and the kind of dispersions one can manufacture using this technique. Three examples with oxide nanoparticles will be emphasized: (1) the production of monodisperse primary particle (D90 < 10nm) suspensions, (2) application of the technology to inorganic and transparent UV absorption and (3) application of the technology to scratch-proof coatings. The key is that the chemomechanical process allows for a chemical control of the nanoparticles' surface if suitable reagents are employed. As a result, the combination of suitable wet phase nano-chemistry and mechanical comminution techniques is a versatile approach to manufacture ready to use nanoparticle formulations for a specific application.