Lightweight\nand Robust Carbon Nanotube/Polyimide\nFoam for Efficient and Heat-Resistant Electromagnetic Interference\nShielding and Microwave Absorption

Abstract

Excellent electromagnetic\ninterference (EMI) shielding ability, light weight, and good heat\nresistance are highly required for practical applications of EMI shielding\nmaterials, such as in areas of aerospace, aircraft, and automobiles.\nHerein, a lightweight and robust carbon nanotube (CNT)/polyimide (PI)\nfoam was developed for efficient and heat-resistant EMI shielding.\nThanks to poly­(vinyl pyrrolidone) (PVP) as a surfactant that not only\npromotes the uniform dispersion of CNTs to form perfect CNT conductive\nnetworks but also can be removed in situ during the polymerization\nprocess, the density of resultant CNT/PI foam is only 32.1 mg·cm^–3, and the EMI shielding effectiveness (EMI SE) is\nup to 41.1 dB, which represents one of the highest EMI SE values compared\nto previously reported polymer-based foams. The CNT/PI foam also achieves\nthe absorption coefficient (<i>A</i>) of up to 82.3%, which\nis very impressive in CNT/polymer foams at comparable EMI SE levels.\nThe PI matrix endows the foam with excellent heat resistance. The\nas-prepared CNT/PI foam presents a higher EMI SE than 35 dB even after\nbeing subjected to the flame of an alcohol burner. Moreover, the compressive\nstrength and compressive modulus are up to 240.9 and 323.9 kPa. These\nresults indicate its certain application potential in the harsh requirement\nof aeronautics and aerospace industries as a highly efficient and\nlightweight EMI shielding material.