Synthesis of a new superabsorbent copolymer based on acrylic acid grafted onto carboxymethyl tragacanth

Superabsorbent polymer (SAP) materials are hydrophilic cross-linked networks that can absorb large quantities of water or aqueous solutions and hold it even under pressure. They can uptake water many hundred times more than their dry weight.1 Three types of SAPs can be produced based on their origin: full synthetic (petrochemical-based), natural (e.g., polysaccharide and polypeptide-based), and hybrid (i.e. grafting synthetic monomers on the natural backbone).2 Synthetic polymer-based SAPs have a high water absorbing capability but these materials can cause environmental problems due to their toxicity and non-biodegradability. As a recent result, SAPs based on the natural polymer have attracted more attention. Carbohydrate polymers such as cellulose, starch, chitin, alginates, etc. are commonly used to synthesize the biodegradable polymers.3 In this study, we have also synthesized a novel hydrogel superabsorbent based on carboxymethyl tragacanth by grafting reaction of the acrylic acid (AA) onto the carboxymethyl tragacanth in an aqueous medium. Furthermore, we have investigated the effects of the reaction conditions on water absorbency and found the optimum conditions to synthesize the superabsorbent with the highest swelling ratio.

Keywords:

Tragacanth gum , Superabsorbent polymer , Graft polymerization , Swelling behavior.