Correlation between Mechanical and Morphological Properties of Polyphenol-Laden Xanthan Gum/Poly(vinyl alcohol) Composite Cryogels

This study aimed to evaluate the effect of the synthesis parameters and the incorporation of natural polyphenolic extract within hydrogel networks on the mechanical and morphological properties of physically cross-linked xanthan gum/poly(vinyl alcohol) (XG/PVA) composite hydrogels prepared by multiple cryo-structuration steps. In this context, the toughness, compressive strength, and viscoelasticity of polyphenol-loaded XG/PVA composite hydrogels in comparison with those of the neat polymer networks were investigated by uniaxial compression tests and steady and oscillatory measurements under small deformation conditions. The swelling behavior, the contact angle values, and the morphological features revealed by SEM and AFM analyses were well correlated with the uniaxial compression and rheological results. The compressive tests revealed an enhancement of the network rigidity by increasing the number of cryogenic cycles. On the other hand, tough and flexible polyphenol-loaded composite films were obtained for a weight ratio between XG and PVA of 1:1 and 10 v/v% polyphenol. The gel behavior was confirmed for all composite hydrogels, as the elastic modulus (G ') was significantly greater than the viscous modulus (G '') for the entire frequency range.

Automated summary

This study aimed to evaluate the effect of synthesis parameters and natural polyphenolic extract on the mechanical and morphological properties of XG/PVA composite hydrogels. The results showed that the compression and rheological properties were correlated with the swelling behavior, contact angle values, and morphological features. Increasing the number of cryogenic cycles enhanced the network rigidity, while a weight ratio of 1:1 for XG and PVA and a polyphenol content of 10 v/v% resulted in tough and flexible composite films. All composite hydrogels exhibited gel behavior, with the elastic modulus being greater than the viscous modulus.