Optimization of chemical treatment process parameters for enhancement of mechanical properties of Kenaf fiber-reinforced polylactic acid composites: A comparative study of mechanical, morphological and microstructural analysis

As advancements in sustainable material science continue, kenaf fiber and polylactic acid (KF/PLA) composites have emerged as promising eco-friendly alternatives. The current research article has focused on improving the physical strength of these KF/PLA composites. Methodologies like Taguchi's and Grey Relational Analysis (GRA) have been employed to identify the most effective ways to enhance the chemical treatment process. The composites were manufactured using an injection molding technique while essential variables were modified. These variables comprised the choice of chemical treatments (sodium hydroxide, potassium hydroxide, or sodium acetate), the concentration of these chemicals (1%, 2%, or 3% w/v), and the duration of treatment (2, 4, or 6 h). These modifications led to the production of diverse KF/PLA composite variants. The physical strength of these modified composites was evaluated using various methods, focusing on their tensile strength, tensile modulus, elongation under tension, flexural strength, flexural modulus, deformability under bending, and impact resistance. A Scanning Electron Microscope (SEM) was utilized to observe the treated and tested samples in detail. The optimal values identified through GRA and mean plots were same for the composite. Improved mechanical properties of KF/PLA were observed when the optimal conditions of A1-B2-C2 (NaOH, 2%, and 4 h) were applied. Although, the morphology of the PLA matrix-based bio composites reinforced with kenaf fiber with different surface-treatments was recorded using AFM analysis in order to further reveal the surface roughness of fibers upon surface modification and dispersion.