The Effect of the Conformation Process on Physicochemical Properties of CMC/Starch Hydrogels

This study discusses the preparation of biopolymeric hydrogels (Biomaterial) via different techniques, such as casting and extrusion, to compare the effects of the process and the use of citric acid as a crosslinker on hydrogel morphology, physicochemical properties, and swelling degree. Casting is widely used for its low cost and space-saving nature, but up-scaling is problematic. Extrusion offers a way to produce materials in large quantities; these materials can undergo mechanical and thermal energy, which can significantly alter their properties. The samples obtained by extrusion had porous surfaces, which are critical for water penetration and swelling of superabsorbent hydrogels. In contrast, the hydrogels produced by casting did not form pores, resulting in a lower degree of swelling. Extrusion increased the swelling degree threefold due to the formation of pores, influencing water absorption and diffusion dynamics, especially in samples with higher starch content, where crosslinking occurred more effectively.