Twin screw extrusion mechanochemical preparation of BiVO4 hybrid pigments for coloring and reinforcing of acrylonitrile-butadiene-styrene

Abstract

The traditional solid or liquid-phase preparation process of clay mineral-based inorganic pigments inevitably involves complex experimental procedures and generation of large volumes of polluting wastewater. To conform to the concept of green chemistry, a cleaner twin screw extrusion followed by high-temperature crystallization technology was developed to prepare low-cost BiVO₄ hybrid pigments based on a natural mixed-dimensional attapulgite clay (MDAPT). It was revealed that the generated shear and extrusion forces during the twin-screw extrusion process effectively promoted the formation of the precursor with the assistance of the colloidal properties of MDAPT. After incorporation of 60 wt% MDAPT, the hybrid pigments obtained at 700 °C presented the best color performance (L^* = 74.76, a^* = 4.24, b^* = 80.84). In view of the synergistic effect of each component, the hybrid pigments served as functional nanofillers for coloring and reinforcing of acrylonitrile-butadiene-styrene (ABS) after being modified with KH-570. At the optimum added amount of 2.75 wt% of hybrid pigments, the tensile strength and bending strength of yellow ABS composites increased by 36.87% and 25.96% compared with that of pure ABS, respectively. Furthermore, it was worth mentioning that incorporation of hybrid pigments also contributed to improving the UV-aging resistance of ABS due to the better absorption and reflection performances of hybrid pigments toward UV and visible light. Therefore, this study is expected to provide a feasible strategy for continuous mechanochemical preparation of low-cost BiVO₄ hybrid pigments for the coloring of ABS with excellent mechanical properties and aging-resistance.