Influence of plasticizer addition and crosslinking process on morphology, water absorption and mechanical properties of sodium alginate films

The effects of sorbitol and formaldehyde on the morphology, water absorption and mechanical properties of sodium alginate films were analyzed. The morphology of the films indicated the presence of small aggregates in the surface of uncrosslinked films, which disappeared with the crosslinking process. The water uptake and percentage of elongation increased with the addition of sorbitol in uncrosslinked films. At the same time, a decrease in tensile strength and Young's modulus occurred. The swelling ratio and water uptake of crosslinked alginate/sorbitol films decreased with an increase in sorbitol content suggesting an enhanced crosslinking density due to the presence of plasticizer.