Effect of Maleated PLA on the Properties of Rotomolded PLA-Agave Fiber Biocomposites

In this work, agave fibers were surface treated using maleated PLA (MAPLA) in order to increase the fiber content (from 10 up to 40% wt.) in polylactic acid (PLA) biocomposites produced by rotational molding and to study the effect of the agave fiber and its treatment on the physical, mechanical and thermal properties of the biocomposites. This chemical modification between agave fibers and MAPLA was evaluated by FTIR spectroscopy. In general the results indicate that MAPLA surface treatment produces a more homogeneous morphology with lower interfacial gaps and overall porosity, especially at higher agave contents. This improved compatibility promoted better stress transfer leading to increased mechanical properties. For example, the tensile strength and modulus of treated fiber composites increased by up to 68% (from 25 to 41 MPa) and 32% (from 1.30 to 1.74 GPa) respectively, in comparison with untreated fiber composites. Fiber surface treatment also decreases hydrophilicity, lowering water absorption and diffusion coefficient. From thermo–mechanical analyses, the damping behavior of the biocomposites decreased with MAPLA treatment since a stronger interface is able to sustain higher stresses and dissipates less energy. Finally, the thermal stability was also improved as a result of better interfacial chemical bonding leading to a 12 °C increase in thermal stability (from 254 to 266 °C).