Effect of processing sequence on recycling of post-consumer automotive bumpers: painted and unpainted variants

As global vehicle production increases, the need for sustainable practices in the automotive sector grows. Despite efforts to promote circular practices like mechanical recycling, the complexity of automotive plastic parts presents challenges. This study investigated the relationship between processing sequence and the mechanical, thermal, and rheological properties of painted and unpainted post-consumer automotive bumpers. Injection-molded specimens of ground unpainted and painted bumpers were obtained with or without previous extrusion. The studied recycled bumpers comprised a PP matrix with ethylene-propylene rubber phase copolymer and talc filler. The results highlighted a significant contribution of this study: the paint coating protected PP-based bumpers from chemical degradation during use, while finely dispersed paint particles within the PP matrix could potentially mitigate thermo-mechanical degradation during extrusion. The pre-extrusion did not enhance mechanical performance. A positive outcome of this study was that simplifying processing steps can optimize efficiency, reduce energy consumption, and increase sustainability, offering a positive outlook for future endeavors in recycled material utilization.