Experimental study demonstrates processing-induced defects reduce tensile strength in alkali-treated pineapple fiber PLA composites, highlighting critical manufacturing trade-offs.
Key Points
To assess the influence of alkali surface treatment, fiber loading, and melt-processing phenomena on the microstructure and mechanical properties of pineapple leaf fiber-reinforced PLA composites.
Compounded untreated (UPF) and alkali-treated pineapple leaf fibers (APF) into polylactic acid (PLA) at 5–20 wt.% loadings using twin-screw melt blending followed by injection molding.
Characterized composite properties using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile testing, void content analysis, water absorption testing, and fracture morphology.
Alkali treatment decreased the average fiber diameter from 138.8 μm to 92.2 μm, while fiber incorporation promoted heterogeneous nucleation with glass transition temperatures between 54–59 °C.
Tensile modulus increased by more than 45%, and the 10 wt.% untreated fiber composite achieved the highest storage modulus.
Tensile and flexural strengths declined at higher fiber loadings and in multiple treated composites due to increased void content, porosity, fiber pull-out, and processing-induced fiber damage.