Abstract
This study deals with a surface modification method in a dry powder/powder handling system. The method is a dry impact blending method which is capable of changing an interactive mixture to composite or encapsulated particles. The effect of powder properties in this method was observed in terms of SEM observations.
Nylon 12 (5.0μm, positive charge) and polyethylene (5.0μm, negative charge) were used as core materials. Polymethylmethacrylate particles (0.4μm) having a positive or negative charge as wall materials were used for each core material for studies on the effect of electrostatic conditions in dry impact blending preparation.
No remarkable differences in the preparation of encapsulated particles were found between the combination of identical charged powders and the combination of opposite charged powders. Namely, surface appearances of the encapsulated particles were the same as those in SEM observations. In another experiments, silica particles (0.6μm) as the wall material and polyethylene (2-10μm) as the core material were used for studies of adhesion mechanism in the preparation.
Silica particles were homogeneously embedded into polyethylene core surfaces because of the mechanochemical effect by hard impact force. Finally, the silica mono-particle layer coated powders were prepared by embedding adhesion mechanism.
It was concluded from these results that one of the important factors for creating surface modification particles is the strength of the impact force in producing mechanochemical effects.
