Polyimine covalent triazine-based framework (PE-CTF) was synthesized from nucleophilic substitution between 2, 4,6- tris (4-formyl phenoxy)- 1,3,5-triazine (TFPTZ) and Hydrazine. Then, it was exfoliated and modified simultaneously through sonication in the presence of Kappa-carrageenan in deionized water. The successful incorporation of the Kappa-carrageenan into the PE-CTF layers was proved by Field emission scanning electron microscopy (FE-SEM) image, energy dispersive spectrometry (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) patterns. In the second part, 0.8, 1.6, and 3.2 %wt of the modified CTF (mCTFs) nanosheets were added to the chitosan and alginate films to investigate the thermal and mechanical properties nanosheets were characterized by FE-SEM, FT-IR, and XRD. Then thermal and mechanical properties. The results show that Young’s modulus, Tensile strength, strain, and Elongation of chitosan nanocomposite film with 1.6 wt% of mCTF were 1284 Mpa, 114.6 Mpa, 16.5%, and 4.9 mm, respectively. Also, for alginate film with 1.6 wt% of mCTF were 2370 Mpa, 133.7 Mpa, 14.1%, and 4.2 mm, respectively. Thermal stability of chitosan and alginate films with mCTF were improved compared with neat ones. The well-dispersed mCTF not only function physical barrier and mechanical enhancement effect but also contribute to graphitization degree of char residues, resulting in enhanced thermal and mechanical performances.