Evaluation of mechanical, thermal, and viscoelastic properties of polylactic-acid (PLA)/ banana peel powder (BPP) composite

This research investigates the thermal, mechanical, and dynamic properties of PLA composites reinforced with banana peel powder (BPP). Composites with varying BPP contents were produced using melt blending followed by compression moulding. Mechanical testing, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) were conducted to evaluate performance. Thermal results highlight the influence of BPP filler content on heat transfer, thermal stability, and the viscoelastic behaviour of the PLA matrix. Morphological characteristics were examined through scanning electron microscopy (SEM) and visual inspection. PLA/BPP composites containing 1 wt%, achieved the highest flexural strength with 1.7x higher than pure PLA, while the 3 wt% composite exhibited the highest thermal resistance. One-way ANOVA test approved significant differences existed based on their increasing BPP wt% shown in F-values against F-critical. Despite being reduced relative to its pure counterpart, the 1 wt% PLA/BPP formulation also recorded the greatest storage and loss moduli. Conversely, an increase in BPP filler content is observed to significantly decrease the damping factor and its overall thermal stability. Agglomeration is shown in poor mechanical performance in 2 wt% and 3 wt% despite having high thermal resistance at temperature past 400°C. This study significantly establishes systematic correlation between filler content and viscoelastic behaviour of PLA/BPP composites, identifying the optimal loading while explaining the degradation mechanisms through morphological analysis.