A two-step process for the preparation of thermoplastic polyurethane/graphene aerogel composite foams with multi-stage networks for electromagnetic shielding

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 scCO(2) 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.