In this research, layered double hydroxide (LDHs) nanoparticles based on zinc/aluminum with nitrate as an interlayer were prepared by co-precipitation method. At first, it was modified by cyanuric chloride bound to 3-amino propyl tri-ethoxy silane (KH550) as the coupling agent. In other experiment, LDH was modified with lissamine yellow as an anionic color to prepare the nanoparticles. The nanocomposites were prepared by adding 4, 8 and 12-wt% of modified nanoparticles through solvent processing with ultrasonic technique. The thermal and mechanical properties of poly (vinyl chloride) and PVC/PMMA were investigated. The structure and morphology of nanocomposites were investigated with Fourier transfer infrared, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy methods. The electron microscopy results showed uniform diffusion of modified nanoparticles in the polymer matrix. FT-IR and XRD studies confirmed that the KH550 is linked to the LDH nanoparticles. The thermal and mechanical properties of nanocomposites with pure PVC and PVC/PMMA mixture significantly improved. Also, the thermal aging stability of the pure polymer was increased with adding the nanoparticles and the results were comfired with the Congo red test by decreasing the exiting of hydrogen chloride from PVC by adding the nanoparticles to the polymer matrix.
