采用3种不同粒径的银包铜粉（Ag@Cu）与乙烯-醋酸乙烯共聚物（EVA）进行熔融共混，分别制备不同质量分数的电磁屏蔽塑料，考察Ag@Cu的不同质量分数和粒径对EVA基电磁屏蔽塑料导电性能、屏蔽性能及力学性能的影响。分别使用马来酸酐接枝乙烯-辛烯共聚物/乙烯-辛烯共聚物（POE-g-MAH/POE）增韧母粒和聚异丁烯（PIB）/萜烯增韧母粒对EVA基电磁屏蔽塑料进行增韧改性，获得高填充电磁屏蔽塑料。结果表明：随着Ag@Cu填充量的增加，EVA基电磁屏蔽塑料的导电性能增加，而力学性能下降，复合材料的渗滤阈值随填料粒径增加而降低，Ag@Cu填充量为80%时，屏蔽效能随填充粒径增加而增加。与POE-g-MAH/POE相比，PIB/萜烯的增韧改性效果最佳，断裂伸长率提升至187.3%，屏蔽效能在30~1 000 MHz范围内保持在70 dB以上，表现出更好的挤出加工性。

Electromagnetic shielding plastics with different mass fractions were prepared by melt blending three kinds of silver-coated copper powder (Ag@Cu) with ethylene-vinyl acetate copolymer (EVA). The effects of different mass fractions and particle sizes of Ag@Cu on the electrical conductivity, shielding properties and mechanical properties of EVA-based electromagnetic shielding plastics were investigated. EVA-based electromagnetic shielding plastics were toughened by maleic anhydride grafted ethylene-octene copolymer/ethylene-octene copolymer (POE-g-MAH/POE) toughening masterbatch and polyisobutylene (PIB)/terpene toughening masterbatch, respectively, to obtain highly filled electromagnetic shielding plastics. The results show that with the increase of Ag@Cu content, the electrical conductivity of EVA-based electromagnetic shielding plastics increases, while the mechanical properties decrease. The percolation threshold of the composites decreases with the increase of filler particle size. When the Ag@Cu filling content is 80%, the shielding effectiveness increases with the increase of filling particle size. Compared with POE-g-MAH/POE, the toughening effect of PIB/terpene is the best, the elongation at break is increased to 187.3%, the shielding effectiveness is kept above 70 dB in the range of 30~1 000 MHz, and it shows better extrusion processability.