Accelerated Weathering of Polylactic Acid/Agave Fiber Biocomposites and the Effect of Fiber–Matrix Adhesion

Abstract

In this study, the accelerated weathering of PLA and its biocomposites produced with agro-industrial waste agave fibers was evaluated to better understand the lifetime of these materials. The effects of the fiber content, the fiber treatment with glycidyl methacrylate grafted PLA, and the fiber/matrix adhesion on the degradation of the materials were also analyzed. The biocomposites were prepared by dry blending, followed by compression molding using untreated and chemically modified agave fibers. The chemical treatment promoted a better fiber–matrix adhesion and lower fiber pull-outs resulting in high tensile and flexural strength values (similar to the neat PLA even with 40 wt% of fiber). Once the modification of the fiber–matrix was observed to be effective, the effect of accelerated weathering over compatibilized and uncompatibilized biocomposites was evaluated. The results showed that after accelerated weathering, the crystallinity of the biocomposites increased significantly, causing that the impact strength remains constant and, in some cases, even improved. At the same time, tensile and flexural properties were noticeably decreased. Nevertheless, the treated fibers which have better adhesion to the matrix led a better resistance to weathering degradation, which is confirmed by higher dimensional stability and lower decreases in tensile and flexural properties than biocomposites with untreated fibers.