CHARACTERIZATION OF PLA-BASED HYBRID COMPOSITES: MECHANICAL AND MORPHOLOGICAL PROPERTIES

Abstract

Sustainable materials and growing environmental concerns have contributed to the development of natural fiber-reinforced polymer composites. Sugar palm fiber (SPF) is renewable, biodegradable, and eco-friendly while waste tyre rubber (WTR) is also useful for improving composite properties. This research focuses on creating poly(lactic acid) as a matrix material for these green composites (PLA) filaments reinforced with SPF and WTR for 3D printing. WTR and SPF were treated with 6 % NaOH and 3 % silane to improve interfacial adhesion with 97.5%PLA:2.5%SPF/WTR. Three different fiber loadings were evaluated 75%SPF:25%WTR, 50%SPF:50%WTR, and 25%SPF:75%WTR. The fabricated filaments from a twin-screw extruder were used to 3D print tensile ASTM D638, and flexural ASTM D790 test specimens with infill densities of 50 %, 70 %, and 100 %. The 75%SPF:25%WTR composite exhibited the best mechanical properties, with a tensile strength of 37.89 MPa and a flexural strength of 54.52 MPa. Consistent performance was observed across infill densities of 50 %, 70 %, and 100 % for 75%SPF:25%WTR highlighting the optimal mechanical characteristics at this fiber loading. Additionally, scanning electron microscopy (SEM) analysis confirmed that the 75%SPF:25%WTR of this combination resulted in superior tensile strength. Enhanced performance is attributed to the improved interfacial adhesion between the treated fibers and the PLA matrix, as well as the uniform dispersion of the fibers within the composite. According to these findings, sugar palm and waste tyre rubber hybrid composites are highly sustainable and high-performance alternatives to petroleum-based plastics.