Nanoparticle (NP)-based polymer nanocomposites have received significant attention in recent years, particularly those based on carboxymethyl cellulose (CMC). This study aims to synthesize and characterize of nanocomposites derived from grafted CMC. Because of the presence of polar functional groups, such as carboxyl and hydroxyl groups, in CMC, which contribute significantly to its strong adsorption capacity in metal structures, some research has indicated that this CMC is effective as a corrosion inhibitor, especially after being coated with NPs, as it protects metal surfaces from corrosion and helps them create a protective layer. In this study, nanocomposites derived from grafted CMC were synthesized. Initial CMC underwent a reaction with thionyl chloride in dimethylformamide (DMF) to produce CMC-Cl [I]. The CMC-Cl[I] reaction with various amines in DMF yields grafted CMC [II-X], which is subsequently blended with the natural biopolymer Chitosan to form blend polymers [XI-XIX]. Nanocomposites were synthesized through the interaction of blend polymers (grafted CMC/CS) with NPs such as magnesium oxide NPs (MgONPs), silver NPs (AgNPs), and gold NPs (AuNPs). The structures of the synthesized nanocomposites were characterized using FT-IR, ¹H-NMR, FESEM, and TEM. An investigation into the corrosion inhibition of blended polymers and nanocomposites on mild steel in 0.1 M HCl was conducted using weight-loss analysis. The results show that nanocomposites have a higher inhibition rate than blended polymers. Grafted CMC/CS/AuNPs [XXXI] reached an inhibition rate of 97% against the corrosion of carbon steel.