Constructing highly oriented segregated structure towards high-strength carbon nanotube/ultrahigh-molecular-weight polyethylene composites for electromagnetic interference shielding

Formation of segregated structure in the conductive polymer composites remarkably improves electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE), however suffers from the deteriorated mechanical performance due to the poor interfacial interaction between the polymer granules. Herein, solid phase extrusion (SPE) was used to prepare mechanically strong carbon nanotube/ultrahigh-molecular-weight polyethylene composites with highly oriented segregated structure. The tensile strength of SPE composites was significantly enhanced to a considerable level of ∼100 MPa, 178% higher than the conventional compression-molded (CM) counterparts (∼36 MPa). It was attributed to the structure orientation induced by the shear flow and compacted granule adhesion facilitated by the high extrusion pressure of SPE. Moreover, SPE composites displayed the comparable electrical conductivity and EMI SE to the CM samples. Besides, an unusual resonance peak appeared on the EMI SE curves for SPE samples due to the special segregated structure, giving a hint of selective EMI shielding.