The effect of soil burial degradation of oil palm trunk fiber-filled recycled polypropylene composites

Soil burial tests were carried out to evaluate the effect of biodegradation on the mechanical properties (tensile, flexural, and impact) and the mass loss of OPT fiber-filled RPP composites, as compared to control samples (virgin PP and RPP without filler). The composite samples were prepared using 30% w/w of OPT filler with a size of 100 μm. Compounding was carried out using a Haake Rheodrive 500 twin-screw compounder operating at 190°C and 8 MPa for 30 min. The effect of biodegradation was performed in a perspex plastic apparatus for 12 months. Assessments of the mechanical properties and the percentage of mass loss were carried out at 3, 6, and 12 months of exposure in soil. The mechanical properties (tensile, flexural, and impact) of materials deteriorate with an increase in exposure time. The effects of biodegradation increase with burial period, i.e., from 0 to 12 months. The tensile properties, flexural properties, and impact strength of the composites decrease by about 38-47%, 37-50%, and 47%, respectively, as compared to the value before the biological test. In contrast, the mass of the composite samples increased by ∼12.7%, whereas for PP and RPP, it increased by around 10.7 and 9.2%, respectively. SEM analysis was conducted to analyze the deterioration and the poor fiber-matrix bonding of composites.