Sustainable utilization of waste printed circuit boards powders in HDPE-wood composites: Synergistic effects of multicomponents on structure and properties

Abstract

Accumulation of millions of tons of waste printed circuit boards powders (WPCBP) are causing serious environmental pollution as it contains lots of toxicant substances. This work had explored the potential use of WPCBP as a reinforcement to replace wood flour (WF) for engineering value added high-density polyethylene (HDPE)-wood composites. Pyrolysis gas chromatography-mass spectrometry, fourier transform infrared, thermos-gravimetric analysis, scanning electron microscopy (SEM) and X ray fluorescence were selected to analyze the physico-chemical properties of WPCBP, and the results showed that the WPCBP contained bromine flame retardants and transition metals. Incorporating WPCBP into HDPE-wood composites improved the notched impact strength, water absorption rates and rheological properties, while it reduced the oxidation induction time (OIT) which was due to the transition metals in WPCBP. When the content of WPCBP and WF fixed at 20 wt % and 10 wt %, the addition of KH-550 and PE-g-MAH simultaneously improved the tensile strength and notched impact strength of the composites which were enhanced by 64.4% and 66.1% compared to those of unmodified samples. All composites containing modifiers showed higher storage modulus and higher interfacial adhesion between the filler and matrix with respect to the original composites. SEM studies revealed that the addition of KH-550 and PE-g-MAH improved the interfacial adhesion between fillers and HDPE matrix. The value of this work lies in the fact that apparent mechanical properties improvement of HDPE composites has been achieved by the incorporation of PE-g-MAH and KH-550 modified WPCBP, which might be fruitful for reducing the production cost of the HDPE-wood composites and brought forward a new way to reuse WPCBP for a sustainable world.