Development of a Yellow Pigment Based on Bismuth and Molybdenum-Doped TiO2 for Coloring Polymers

Abstract

An inorganic yellow pigment based on TiO2 containing minor amounts of bismuth and molybdenum compounds was developed without rare earths or highly toxic elements. The material was produced starting from a composition of 99% (mol%) of rutile TiO2 and 1% of MoO3, which were previously mixed and calcined at 1200 degrees C. The composition consisted of 99.8% of the above mixture and 0.2% of bismuth(III) nitrate basic hexahydrate. This powder mixture was homogenized and calcined in a tubular furnace at 1200 degrees C, applying different heating rates: 1, 30, 40, and 60 degrees C/min. The yellow color was attributed to the presence of -Bi2O3, *-Bi2MoO6, and Bi2Ti2O7 phases. The powder particle size proved suitable for using the material as an inorganic pigment for polymers. The technological application of the pigment was tested in high-density polyethylene.