Waste‐Furniture Particleboard as Filler in Injection‐Molded Polypropylene Composites: Effects of Aqueous Cleaning and MAPP Compatibilization

ABSTRACT Waste‐furniture particleboard is a secondary resource, but adhesive, coating, and mineral residues hinder its reuse. This study assessed its feasibility as a filler for injection‐molded polypropylene (PP) and examined how aqueous cleaning affects its response to maleic anhydride‐grafted PP (MAPP). Untreated waste‐furniture filler (WF) and cleaned waste‐furniture filler (CWF) were incorporated at 30 wt%, with or without 5 wt% MAPP; clean poplar flour served as a reference. Cleaning reduced ash content from 4.7% to 1.1% and slightly improved the mechanical properties of composites without MAPP. With MAPP, however, WF outperformed CWF; its tensile and flexural strengths increased by 31.53% and 30.05%, respectively. Rheological and thermal analyses showed changes in melt and crystallization behavior, while DFT calculations suggested possible interactions between residual organic groups and MAPP. These findings offer a new perspective on valorizing waste‐furniture particleboard in injection‐molded composites.