Facile and scalable extrusion fabrication of multifunctional cobalt blue nanocomposite pigments based on natural mixed-dimensional palygorskite clay

Scalable preparation of environmental-friendly and high-performance functional nanomaterials based on the natural clay minerals has been one of the mainstream trends in the fields of materials synthesis. Herein, a mechanochemical extrusion strategy was developed for the continuous preparation of cobalt blue (CoAl ₂O ₄) nanocomposite pigments based on natural mixed-dimensional palygorskite clay (MDPal). It was revealed that the Si-OH groups of MDPal interacted with the metal ions during the extrusion process and contributed to the shaping formation of the precursor. The MDPal provided component doping for adjusting the color properties of nanocomposite pigments and the mixed-dimensional morphology served as benign substrate for supporting CoAl ₂O ₄ nanoparticles without obvious aggregations. It was worth noting that the nanocomposite pigments prepared using raw MDPal presented satisfactory chroma values ( L ^⁎ = 28.63, a ^⁎ = −4.19, b ^⁎ = −37.47, C ^⁎ = 37.79). In addition, the blue intensity of nanocomposite pigments could be facilely adjusted by controlling the component content of MDPal based on the acid-etching structural whitening with oxalic acid to remove the color-causing components in MDPal, and the optimum b ^⁎ value reached −48.03. Owing to the synergistic effect of CoAl ₂O ₄ nanoparticles and MDPal, the obtained nanocomposite pigments presented promising application prospect for the coloring of underglaze ceramic, coloring and reinforcing of acrylonitrile butadiene styrene as well as colorful anticorrosion coating. Therefore, this study was expected to develop a feasible strategy for scalable preparation of low-cost and multifunctional CoAl ₂O ₄ nanocomposite pigment via cleaner full component utilization of natural MDPal.