Original tools for xanthan hydrophobization in green media: Synthesis and characterization of surface activity

Xanthan gum (XG) was modified through esterification using various alkenyl succinic anhydrides in green media. FTIR and NMR spectroscopy confirmed that the alkenyl succinic hydrophobic groups were successfully grafted on octenyl-grafted (XG-C8), dodecenyl-grafted (XG-C12), and hexadecenyl-grafted (XG-C16) xanthan backbone. Grafted chains were evaluated by degree of succinylation (DS). Modification enhance the surface activity of xanthan by decreasing surface tension from 72 until 37 and 58 mN/m due to respectively long alkenyl chain for XG-C16 (DS = 2.2 ± 0.2%) and high grafting rate for XG-C12 (DS = 16.9 ± 1.9%). These original tools are of great interest to optimize both the DS and the properties of xanthan gum by varying reaction parameters like pH range, reaction time and the mole excess of the grafting reagents to xanthan monomeric units.