The core-shell theory presents a new easy route to obtaining a high performance, eco-friendly extender pigments with concomitant cost savings. This theory is based on depositing a surface layer of expensive efficient pigment on a cheap extender expressing the bulk. The combination of both core and shell compounds led to production of new pigments with improved properties different from the individual components. Techniques like layer-by-layer deposition, sol-gel synthesis, laser pyrolysis, heterocoagulation and flame synthesis have been used to synthesize various kinds of core-shell pigments. Most of these methods, involve multiple steps and cutting-edge technologies which makes it difficult to replicate in bulk scale. In this study, a simple chemical technique has been used to prepare core-shell extender pigments based on Nigerian indigenous clays as core and titanium dioxide as shell. The prepared core-shell extender pigments were characterized using X-ray fluorescence and scanning electron microscopy. The physico-chemical properties of these extender pigments were also evaluated according to ASTM measurements. The study showed that the prepared core-shell pigments were non-toxic and environmentally friendly. They are of low cost and can be incorporated in semi-gloss paints, paper, rubber and plastic composites without much effect on the volume and which can subsequently lead to considerable cost savings as compared to titanium dioxide and the precursor local clays. The performances of these pigments showed that they combine the properties of both their counterparts, and have the potential to overcome their disadvantages, e.g., low hiding power of clays, photochemical activity of titanium dioxide.
展开▼
