Effect of charge balancing cations on the viscoelastic and thermal properties of welan

Abstract

Welan is a branched polymer in the gellan family of polysaccharides. It has good compatibility with divalent calcium ions with a potential use in cementing applications. It is also been utilized as an anti-washout material for underwater concrete placement. Herein, influence of divalent cations Ca2+, Ni2+, Mg2+, Zn2+ and Sr2+ on the gelling and thermal properties of welan have been investigated. The viscoelastic properties reveal strong gelation behavior that are stable up to 80 °C. Among all the five cations Ni2+, Ca2+, Zn2+ and Sr2+ are suited well, compared to Mg2+ ions, to promote favorable interactions among the welan chains leading to stronger junction zones and elastic moduli. The melting peak and enthalpy are dependent on the nature and size of the divalent cation. The outcome is deemed to aid to expand the welan utility in food and non-food applications.

Keywords

• Welan
• Divalent cation
• Rheology
• Thermal properties