A Yellow Lead-Free Pavement Marking Paint Based on Hybrid Dye-Clay Nanopigment: Morphological, Thermomechanical, and Photophysical Properties

Abstract

This study utilized a yellow hybrid dye-clay nanopigment (DCNP) in a paint formulation to prepare a lead-free, eco-friendly pavement marking paint as an alternative to the conventional lead chromate (PbCrO4) paints. Two paint formulations based on DCNP and PbCrO4 were fabricated using a mechanical mixing method followed by sonication. The paint films were obtained via solution casting. The morphological property investigation demonstrated that the DCNP was well dispersed in the polymeric paint film with the formation of a partially intercalated/exfoliated structure. The film colored with DCNP showed a 75% improvement in storage modulus (E′), much higher than that of the film filled with PbCrO4 (39%). DCNP increased the glass transition temperature (Tg) of the paint by 5 °C, implying a favorable impact of this pigment on the pavement marking’s thermomechanical stability. The photophysical characterization revealed that the brilliant yellow color of the paint featured the yellow component value (+b*) of 69.9 units. Furthermore, the pavement marking standard colors were achieved with a considerably smaller amount of colorant when using DCNP due to its exceptional color strength. In conclusion, the remarkable functional properties of the nanopigment DCNP indicate its great potential as a promising alternative to lead chromate in pavement markings.