Carboxymethyl cellulose from Opuntia ficus-indica (Cactaceae) for cross-linked films.

Opuntia ficus-indica (Cactaceae) is an attractive renewable resource from arid and semi-arid regions of the world, including the north of Africa and Tunisia. It has suitable potential for use as a cellulose source for producing carboxymethyl cellulose (CMC). The chemical composition of fibers obtained from underground (roots) and aerial (trunk) parts of Opuntia ficus-indica, such as cellulose, holocellulose, lignin and ashes, was determined using normed and standardized methods. Individualized cellulose fibers were extracted from both raw materials using an eco-friendly delignification process based on soft treatment with sodium hydroxide/hydrogen peroxide mixtures followed by mechanical operation. The extracted cellulose fibers were carboxymethylated using sodium hydroxide and mono-chloroacetic acid, in the aqueous ethanolic medium. In this work, novel eco-friendly hydrogel films were synthesized based on high-quality carboxymethyl cellulose "CMC-R" from the roots ([DS] = 0.64) and "CMC-T" from the trunk ([DS] = 0.97) cross-linked with citric acid. The produced hydrogel films from both CMCs have various morphological structures, acceptable mechanical properties, and improved barrier behaviors. However, CMC hydrogel films from Opuntia ficus-indica are totally biodegradable within 20 days and became good candidates to replace synthetic polymers in packaging films. [ABSTRACT FROM AUTHOR]