▎ 摘　　要

NOVELTY - Preparation of low-percolation graphene/macromolecular electromagnetic shielding material comprises drying graphene oxide nanosheet (GONS); mixing dried GONS and deionized water, ultrasonically stirring, adding ultrahigh-molecular weight polyethylene (UHMWPE) particles and ultrasonically stirring, removing solvent, and drying; and prepressing obtained GONS/UHMWPE composite particles at room temperature and greater than or equal to 500 MPa for greater than or equal to 3 minutes, hot-pressing at 250-280 degrees C and less than or equal to 0.1 MPa for more than 30 minutes under nitrogen protection, and cooling to room temperature at atmospheric pressure. USE - Method for preparing low-percolation graphene/macromolecular electromagnetic shielding material (claimed). ADVANTAGE - The method is simple, easy to implement and suitable for large-scale production; and has low cost. Since graphene oxide is reduced in-situ at high temperature in hot-pressing preparation process, agglomeration of graphene oxide in chemical reduction process is avoided and the composite material has low conductive percolation value, high conductivity and high electromagnetism shielding performance. DETAILED DESCRIPTION - Preparation of low-percolation graphene/macromolecular electromagnetic shielding material comprises: (A) drying GONS with diameter of 200-1000 nm and thickness of 0.9-1.5 nm until water content of less than 0.01 wt.%; (B) mixing dried GONS and deionized water at weight ratio of 1:40-200, ultrasonically stirring to prepare uniform dispersion, adding UHMWPE particles and ultrasonically stirring, removing solvent by vacuum distillation, and drying at less than 60 degrees C until water content of less than 0.01 wt.% to prepare GONS/UHMWPE conductive composite particles; and (C) prepressing GONS/UHMWPE composite particles at room temperature and greater than or equal to 500 MPa for greater than or equal to 3 minutes, hot-pressing at 250-280 degrees C and less than or equal to 0.1 MPa for more than 30 minutes under nitrogen protection to avoid UHMWPE high-temperature crosslinking, and cooling to room temperature at atmospheric pressure. The shielding material comprises 94-99.7 wt.% UHMWPE and 0.3-6 wt.% GONS. The UHMWPE has weight-average molecular weight of 400-6x 106. The GONS is prepared by improved Hummers method.