The interactions in ternary system made of xanthan gum, Carbopol 940 and anionic/nonionic surfactant

The development and optimization of systems consist of polymers and surfactants are strongly related to the presence of interactions between them. Therefore, the interpolymer complexes between biopolymer xanthan gum and synthetic polymer Carbopol 940 were investigated before and after the addition of surfactant. The mechanism of interactions in ternary system consisted of xanthan gum, Carbopol 940 and anionic surfactant (sodium dodecylsulfate) as well as nonionic surfactant (Tween 80) was studied by the combination of different techniques such as viscometry, conductometry, tensiometry, spectrophotometry and fluorimetry. Xanthan gum and Carbopol 940 formed complexes through hydrogen bonding and hydrophobic interactions. Therefore, the calculated specific viscosities of polymer blends were much lower than experimentally determined values. Namely, both polymers participated in the association process with sodium dodecylsulfate or Tween 80. In case of anionic surfactant hydrophobic interactions between sodium dodecylsulfate and xanthan gum-Carbopol 940 complexes exist together with electrostatic repulsive forces between the same charged groups. Tween 80 interacts with xanthan gum-Carbopol 940 complexes through hydrogen bonds and hydrophobic interactions. The formed xanthan gum-Carbopol 940 complexes with sodium dodecylsulfate or Tween80 could find their application by optimizing the interactions in the system of xanthan gum and Carbopol 940 using the appropriate concentration of surfactant.