Influence of layering variation with addition of bio-fillers on mechanical and thermal performances of hybrid polyester composites

The extensive application of composites reinforced with synthetic or natural fibers and bio-fillers represents a recent advanced trend in research. This research seeks to assess the optimal ratio of wood dust (WD) and fish scale powder (FSP) for forming a hybrid filler mix to reinforce Palmyra Palm leaf stalk (P)/Glass (G) polyester laminate, aiming to improve its mechanical and thermal properties. The ideal ratio is identified by evaluating the mechanical properties of various weight fraction combinations of WD and FSP filler in polyester. The test results showed that the optimal filler hybridization ratio is 5 wt.% WD and 10 wt.% FSP. Hybrid laminates are then produced by combining equal layers of glass and palm leaf stalk fiber in different stacking configurations, incorporating an optimal mixture of hybrid fillers. The experimental findings revealed that, the inclusion of an optimal blend of WD and FSP filler results in improvements in mechanical properties, with a 51.93% increase in tensile strength, a 36.27% boost in flexural strength, a 20.48% rise in impact resistance, and a 10.08% enhancement in micro-hardness. Additionally, the findings revealed that the laminate with GPPG stacking order shows the highest mechanical properties compared to other stacking sequences. To further examine the thermal degradation and various failure mechanisms, Thermo-gravimetric analysis (TGA) and fractography study using a Scanning Electron Microscope (SEM) are conducted.