Preparation and physical properties of CeO₂ doped and modified epoxy resin composites

Abstract Epoxy resin is a widely used polymer material, while its low mechanical properties and thermal stability limit its use in extreme environments such as high temperature and high pressure. In order to improve the performance of EP, this study assessed the enhancement of mechanical properties and thermal stability of EP by stearic acid‐modified n‐CeO₂ and its mechanism. Laser particle size analyzers, transmission electron microscopes, and other instruments were used to characterize n‐CeO₂. Universal testing machines, thermogravimetric analyzers, and other instruments were used to test n‐CeO₂/EP nanocomposites. The results show that fatty acids effectively coated the surface of n‐CeO₂, reducing its central particle size from 0.248 μm to 0.193 μm and improving its dispersion and compatibility. The tensile, flexural, impact strength, maximum decomposition temperature, and glass transition temperature (Tg) increased by 382%, 554%, 698%, 5%, and 10%, respectively with 2 wt% filler content. The scanning electron microscopy (SEM) images showed that the addition of n‐CeO₂ induced plastic deformation and crack formation in the EP matrix, which enhanced the toughness of the composite material. This study provided the effective methods and basis for the preparation of high‐performance n‐CeO₂/EP nanocomposites. Highlights Nano cerium dioxide was modified to improve its dispersion by using stearic acid. High‐performance nanocomposites were prepared by using modified nanoparticles. The stiffness and toughness of the epoxy resin were enhanced by adding n‐CeO₂. Thermal stability and heat resistance of the epoxy resin were improved by doping n‐CeO₂. SEM images of the impact section showed that n‐CeO₂ can prevent crack propagation.