PROPERTIES OF COMPOSITE POWDER BY SURFACE MODIFICATION OF CORE INORGANIC PIGMENTS WITH TITANIUM DIOXIDE

摘要

Dry impact-blending method was used to prepare functional composite-pigments using inorganic materials such as ground calcium carbonate(GCC),clay,and talc as core particles,and titanium dioxide as surface modifying fine particles.Core powder and fine powder were mixed at suitable ratios to form ordered mixtures,and in this course the energy caused by fine powder adhering to core particles was measured and utilized in examining the efficiency of particle surface modification.Then the mixtures were subjected to be composited by impact and friction forces resulting from very high-speed air circulation.The surface modified pigments were dispersed in water,and their electro-kinetic properties such as charge demand and Zeta potential were measured.The difference between simple mixing and composite modification on brightness and scattering index were also compared.All the results revealed that significant improvements of powder properties can be achieved through the surface modification method.