Numerical Simulation of the Adhesion Interface in Injection Overmolding of Virgin ABS with Debrominated ABS from Post-Consumer E-Waste

The growing volume of waste electrical and electronic equipment (commonly known as e-waste or WEEE) plastics presents significant environmental and regulatory challenges, particularly due to the presence of brominated flame retardants (BFRs). This study presents groundbreaking research on the mechanical recycling of brominated acrylonitrile butadiene styrene (ABS) derived from real post-consumer WEEE. It evaluates the effectiveness of BFR extraction and explores the feasibility of simulating injection overmolding using the debrominated polymer. The extraction process achieves BFR removal rates exceeding 94%, reducing the final BFR content, mainly those identified as persistent organic pollutants (BFR-POPs), to below 50 ppm, thus complying with Directive 2019/1021/EU. Compared to virgin ABS (vABS), the debrominated ABS maintains its physico-chemical characteristics with increased elastic modulus, stress at yield, and stress at break, although impact toughness is reduced. Moldflow simulations reveal that the polymer interface temperature and duration above ABS's glass transition temperature are insufficient for optimal polymer chain auto-diffusion. To maximize interlayer adhesion, both mold and material temperatures must be increased. These findings confirm the technical feasibility of BFR removal and reuse of ABS in value-added applications, contributing to sustainable material development and circular economy objectives for WEEE plastics.