Granitic quarry waste as a dual functional filler for high density polyethylene‐based composites: Mechanical and microwave absorbing properties

Abstract

Cost-effective polymeric composites were successfully prepared by melt blending granitic quarry waste (GQW) with high-density polyethylene (HDPE). The GQW is a waste generated during the production of manufacture fine aggregates (MFA) from crushed gneiss rock and contains significant amount of mica with iron in its structure. Different sieving and milling procedures were employed. The materials were characterized by mechanical and dynamicmechanical properties and scanning electron microscopy. Moreover, the influence of the GQW on the microwave absorbing properties in the X-band frequency range was investigated. The presence of mica and iron compound in the GQW provides a dual function to the filler: toughening agent with microwave absorbing capacity. Indeed, the addition of 5 wt% of GQW previously sieved and milled by dry or wet-grinding approach resulted in composites with outstanding toughness, modulus and elongation at break. Simulated RL studies revealed electro-magnetic attenuation of À25 dB at 8.7 GHz. Such successful use of a waste generated in the production of a concentrate (MFA) not only contributes to the economics of the quarrying operation, but also to its environmental sustainability, since it replaces disposal of this product, which could lead to dust emissions, given its fine size and low moisture content.

Thermo‐mechanical properties of polyethylene composites filled with soapstone waste

“…Similar observations were reported with for PE composites filled with commercial talc 8 and sandalwood. 52 In the case of PE filled with granitic waste, 4 the improvement in dynamic storage modulus was observed mainly in the glassy region, while at higher temperatures the filler effect on stiffness was negligible.…”

“…In addition, significant improvements in the performance of commercial polymers can be achieved, since inorganic fillers can reasonably be integrated into thermoplastic matrices, allowing for optimization of specific properties 3 . In fact, Moura et al 4 reported that the incorporation of granitic quarry waste into polyethylene led to improvements on mechanical performance, associated with interesting microwave absorbing properties. It has also been shown that marble waste is promising alternative filler, capable of improving the flexural strength, elastic modulus and wear resistance of different thermoplastic matrices 5–7 …”