The study examined the properties of epoxy composites with dendritic copper (Cu) particles through various tests, including FTIR, DSC, TGA, electrical conductivity, and mechanical tests. The addition of Cu particles to the composites improved their electrical conductivity and mechanical properties, particularly tensile strength and flexural modulus. The Tg temperature of the composites could be adjusted by varying the Cu particle ratio. Notably, in the study, we prepared composites with varying Cu particle concentrations, specifically at ratios of 1%, 2%, 3%, 4%, 5%, and 6%, and observed distinct effects on the properties of the epoxy-Cu composites. Although there was no chemical bonding between the epoxy and Cu particles, the Cu additive acted as a pinning agent, restricting the movement of the polymer chains. This suggests that incorporating small amounts of Cu into epoxy composites can enhance their properties, making them suitable for applications in the electrical and electronics industry. Additionally, we evaluated the shielding properties of selected epoxy-based composites incorporating copper powder against gamma radiation with energies of 59.5 keV, 661.6 keV, and 1332.5 keV, and also investigated the composites' ability to attenuate gamma rays, recommending specific composites (ECU6, ECU1, and ECU2) for different energy levels of gamma rays. SEM examinations showed that the addition of Cu particles significantly altered the microstructure and mechanical properties of the composites, resulting in an irregular and rough fracture surface and decreased structural integrity.