Effect of natural weather aging on the properties of poly(vinyl alcohol)/starch/graphene nanocomposite

Degradation has a significant impact on the crystallinity of biodegradable polymers. This work was undertaken to investigate the degradation of a poly(vinyl alcohol) (PVA)/starch blend and its nanocomposites with graphene under natural weathering conditions in Dhahran, Saudi Arabia. Changes in crystallinity, mechanical properties, molecular structure, and morphology of the nanocomposites during the aging period have been observed and inferred. The thermal and spectroscopic results demonstrated the dissolution of the amorphous phase during early stages of exposure followed by the deterioration of the crystalline phase in later stages. Morphological micrographs showed that the surface of the nanocomposites had fewer defects compared to the PVA/starch blend. PVA/starch/graphene nanocomposites showed a remarkable retention in total crystallinity compared to the PVA/starch blend during the aging period. The incorporation of graphene into the PVA/starch blend made both the polymers less vulnerable to environmental degradation, and these nanocomposites could therefore be suitable as packaging films for use in outdoor applications.