The Impact of Agave (Agave Tequilana) Powder on the Thermal and Mechanical Properties of PLA Bio-Based Composites

Abstract

This work investigates fully bio-based PLA composites reinforced with agave (Agave tequilana) agro-industrial residues, without chemical treatment or coupling agents, as a sustainable strategy for material valorization. Agave powder was incorporated into PLA at 3 to 20 wt.% by solvent casting. The resulting films were characterized by FT-IR, TGA, DSC, SEM, and mechanical testing to evaluate interfacial interactions, thermal behavior, morphology, and mechanical performance. FT-IR indicated predominantly physical interaction between PLA and agave particles, with no evidence of chemical bonding. Thermal analysis showed improved stability at low filler contents (3–5 wt.%), due to a barrier effect, while higher loadings reduced thermal resistance due to the decomposition of lignocellulosic components. Mechanical performance strongly depends on filler content. Agave incorporation did not produce a systematic reinforcing effect relative to neat PLA and progressively reduced tensile deformability, with the most pronounced deterioration observed at 20 wt.%, associated with poor interfacial adhesion, particle agglomeration, and reduced matrix continuity. SEM observations supported these findings, revealing increased heterogeneity, void formation, and interfacial debonding at higher filler contents. Overall, untreated agave powder acts primarily as a filler rather than an effective mechanical reinforcement, with performance governed by particle dispersion and interfacial compatibility with PLA.