Abstract Polypropylene (PP) composite pellets with 5–30 wt% carbon black (CB) were blowed with subcritical CO2, and then employed as building blocks to assemble into large-sized PPCB foam broad with dimension of 60×30×10 cm3 by steam-chest molding. The resultant PPCB foams showed a closed-cell structure with cell size in hundreds of micrometers, which endowed them with low densities of 0.034–0.117 g/cm3. Due to the high CB content of 30 wt%, the foam exhibited a high conductivity of 1.3 S/m and an electromagnetic interference (EMI) shielding effectiveness (SE) of 20–31 dB over the broadband frequency range of 6–18 GHz, corresponding to ~99%–99.92% shielded electromagnetic energy. Further increasing the sample thickness from 4 to 6 cm led to much higher SE of 41 dB (~99.992% shielded power) over 8–12 GHz. More importantly, all PPCB foams possess an absorption-dominant shielding mechanism, and for the foams containing 25–30 wt% CB, their absorption coefficients are as high as 0.80–0.97, indicating ~80%–97% absorbed power. The unique features, as well as the foaming technologies, make our lightweight PPCB foams very potential in the scale-up manufacture of advanced EMI shields.

中文翻译：

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聚丙烯/炭黑复合泡沫的蒸汽模塑作为具有高吸收率的宽带 EMI 屏蔽

摘要 将含有 5-30 wt% 炭黑 (CB) 的聚丙烯 (PP) 复合颗粒用亚临界 CO2 吹制，然后作为构件通过蒸汽组装成尺寸为 60×30×10 cm3 的大尺寸 PPCB 泡沫。 -胸部成型。所得的 PPCB 泡沫显示出闭孔结构，泡孔尺寸为数百微米，这使它们具有 0.034–0.117 g/cm3 的低密度。由于 30 wt% 的高 CB 含量，泡沫在 6-18 GHz 的宽带频率范围内表现出 1.3 S/m 的高电导率和 20-31 dB 的电磁干扰 (EMI) 屏蔽效率 (SE)，对应于 ~99%–99.92% 的屏蔽电磁能。进一步将样品厚度从 4 厘米增加到 6 厘米，导致 8-12 GHz 的 SE 高得多，达到 41 dB（~99.992% 屏蔽功率）。更重要的是，所有 PPCB 泡沫都具有以吸收为主的屏蔽机制，对于含有 25-30 wt% CB 的泡沫，其吸收系数高达 0.80-0.97，表明吸收功率约为 80%-97%。独特的功能以及发泡技术使我们的轻质 PPCB 泡沫在高级 EMI 屏蔽的规模化制造中具有很大的潜力。