In the case of the Sfilms, every parameter significantly changes
during storage. Thefilms become harder, more resistant to break,
but more brittle and less stretchable, as previously reported by
Cano et al. (2014). The stiffness of the PVA films also slightly
increased, but their resistance to break and extensibility did not
change, the latter being much higher for PVA than for the Sfilms.
The blendfilms were the least stiff, with no significant differences
between blends; the elastic modulus slightly increased during
storage, especially when the S ratio was the greatest. Thesefilms
also exhibited the lowest resistance to break, while maintaining
high values of stretchability. Both resistance and extensibility
decreased when the S ratio increased in the blend.