Investigations on the interactions between xanthan gum and poly(vinyl alcohol) in solid state and aqueous solutions

In the present study, the polymer mixtures based on an anionic polysaccharide, namely xanthan gum (XG), and a neutral polymer, poly(vinyl alcohol) (PVA), were investigated by FTIR spectroscopy, viscometry and zeta potential measurements. The hydrogen bond intermolecular interactions between functional groups of xanthan gum and those of PVA were evidenced by FTIR spectroscopy. The experimental viscometric data of polymer mixtures in aqueous solutions were interpreted by using the Wolf approach. This model allows the determination of the intrinsic viscosity and other hydrodynamic parameters irrespective of structural characteristics of macromolecular chains, polymer mixture composition and polymer concentration. The chain conformation and polyelectrolyte feature of xanthan gum have a high contribution on the behavior of XG/PVA mixtures; high values of the hydrodynamic parameters were obtained for XG rich polymer mixtures. The viscometric results and FTIR analysis revealed the formation of intermolecular associations between XG and PVA due to the hydrogen bonds interactions. The absolute value of the zeta potential for XG/PVA mixtures decreases as the poly(vinyl alcohol) content in the polymer mixtures increases.