Synthesis and characterization of new unsaturated esters of Gellan Gum

A series of Gellan Gum unsaturated esters by addition of free radical polymerizable groups, which can be polymerized under mild conditions to design biodegradable three-dimensional networks having hydrogels properties, were synthesized by esterification under various conditions. Different degrees of functionalization were obtained either homogeneously in water with acrylic acid or heterogeneously with acryloyl chloride and maleic anhydride in organic solvents. Acrylate and maleate groups determination was carried out by ATR-FTIR and 1H liquid NMR techniques. The degree of substitution as determined by 1H NMR could be controlled by varying the chemical nature of functionalization agent, reaction time and temperature. Maleic anhydride presents a higher reactivity as compared to acrylic acid and acryloyl chloride.