Enzymatic synthesis of sodium alginate‐g‐poly (acrylic acid) grafting copolymers as a novel printing thickener

Abstract Grafting modification is a common method for improving the specific properties of polysaccharides. Herein, we synthesised sodium alginate‐g‐poly (acrylic acid) (NaAlg‐g‐PAA) as a novel printing thickener via catalysis of horseradish peroxidase and hydrogen peroxide in the presence of acetylacetone. The synthesised products were characterised by Fourier Transform–infrared spectroscopy and polar nuclear magnetic resonance spectroscopy, which confirmed that the PAA was successfully grafted onto the hydroxyl groups at carbon atoms (C2) of sodium alginate. The optimal grafting percentage and grafting efficiency reached 51% and 96%, respectively. Compared with native sodium alginate, the grafted copolymer NaAlg‐g‐PAA exhibited better thermal stability, rheological and printing properties. This work provides an efficient and promising approach for modifying polysaccharides like alginates and could be used as an alternative to conventional chemical modification.