Characterisation and properties of aluminium/zinc oxide composites as catalytic gases from depolymerisation of low density polyethylene to liquid oil

Abstract

The effects of addition zinc oxide (ZnO) or magnesium trisilicate (MTS) in aluminum (Al) matrix composites on physical and mechanical properties at different sintering temperature were studied. The Al/ZnO and Al/MTS composites prepared by powder metallurgy (PM) method. The composites were mixed using a milling machine at a speed of 131 rpm with ball to powder weight ratio is 10:1, then compressed at 200 MPa for 2 minutes. The results show that the additions of ZnO or MTS in Al composites have increased the density and hardness but decrease the compressive strength of the composites. The Al/ZnO or Al/MTS composites sintered at 750 °C have higher density, hardness and compressive strength than composites sintered at 650 °C. The effect of different sintering temperature gives effect to intensity of the composites. The microstructure of Al/ZnO or Al/MTS sintered at 750 °C show better interaction between filler and Al matrix. The effect of stearic acid or zinc stearate in Al/ZnO composites has increased the hardness and compressive strength of composites but density reduced at sintered 750 °C. The XRD patterns of Al/ZnO composites with stearic acid or zinc stearate show the changed in intensity peak of composites. The presence of stearic acid and zinc stearate as binder improved the adhesion and interaction between ZnO and Al matrix composites. The Al/ZnO composites with zinc stearate have higher physical and mechanical properties compared to other composites. The applied of Al/ZnO composites with zinc stearate as catalyst in the depolymerisation of low density polyethylene (LDPE) has produced yield 76.22 % of liquid oil. The liquid oil product consists of light hydrocarbons such as gasoline was proven by using gas chromatography - mass spectrometer (GC-MS).