Sustainable and Ecological Poly (Vinyl Alcohol)/Agave Fiber-Based Films: Structural Features post Composting Process

Sustainable poly (vinyl alcohol)/Agave fiber-based films were obtained by the melt mixing process. The structural features of films containing unmodified and modified Agave fibers after 90 days of composting were studied. The results indicated that more than 10% of the dry weight of films remained after composting. Thus, the weight loss differences in the material were attributed to a partial disintegration process instead of complete biodegradation or mineralization. The SEM analysis showed degraded fibers in the matrix, which left hollow areas that promoted film fragmentation. Regardless of the fiber type, all films showed a decrease in lignocellulosic components (waxes, pectin, hemicellulose) and crystallinity, as FTIR, TGA and XRD analysis indicated. Furthermore, DMA analysis corroborated that after 90 days, the chain motion of the main PVA chain (alpha transition) decreased due to the plasticizer exudation. Meanwhile, an increased movement of side chains (beta transition) was observed, indicating that more amorphous regions are available for degradation. The results could be of interest to packaging industries that develop biodegradable materials since these findings showed that the Agave fibers waste disintegrated faster than the polymeric PVA matrix, which led to obtaining microplastics instead of the total disintegration of the film.