Abstract A two-step method as follows of preparing thermoplastic polyurethane/graphene aerogel (TPU/GA) composite foams with multi-stage network were used for the first time. TPU/GA composites with 3D network were obtained through the vacuum assisted impregnation using the GA as template firstly, and the cellular structure was then introduced by scCO2 foaming. It was revealed that the electrical conductivity of the TPU/GA composite foams reached 50 S/m at the GA content of 2 wt%, and the EMI shielding value of which was 34.3 dB, resulting from the interconnected graphene networks in TPU/GA composite foams. In addition, EMI shielding absorption coefficient A was improved because of the increased paths for EMI waves in TPU/GA composite foams. It demonstrated an alternative method for preparing flexible polymer/graphene composite foams with favorable EMI shielding absorption performance.

中文翻译：

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用于电磁屏蔽的多级网络热塑性聚氨酯/石墨烯气凝胶复合泡沫的两步制备方法

摘要 首次采用如下两步法制备具有多级网络的热塑性聚氨酯/石墨烯气凝胶(TPU/GA)复合泡沫材料。首先以GA为模板通过真空辅助浸渍获得具有3D网络的TPU/GA复合材料，然后通过scCO2发泡引入多孔结构。结果表明，当 GA 含量为 2 wt% 时，TPU/GA 复合泡沫的电导率达到 50 S/m，EMI 屏蔽值为 34.3 dB，这是由 TPU/GA 复合材料中相互连接的石墨烯网络引起的泡沫。此外，由于 TPU/GA 复合泡沫中 EMI 波的路径增加，EMI 屏蔽吸收系数 A 得到改善。