Ultra-light weight, water durable and flexible highly electrical conductive polyurethane foam for superior electromagnetic interference shielding materials

Abstract

An inexpensive light weight radiation shielding materials have been fabricated by one step, facile technique avoiding toxic volatile organic solvents. Herein, we adopted ‘dip coating and drying’ method to prepare high surface area specialty conductive black (Ketjen-600JD) loaded polyurethane (PU) composite foam. The non-ionic surfactant stabilized black particles showed promising improvement in electrical conductivity (exceptionally low percolation threshold concentration) and water durability. The morphological analysis from electron microscopy and 3D micro computed tomography supports uniform conducting pathway formation on to the cell walls of the cellular PU system. The PU foam surprisingly showed no severe drop of porosity even after dipping in high carbon black dispersion. This efficiently supports the micro structural integrity of the foam composites which has been normally retained as the pristine foam. The EMI shielding value of the composite foam for only 2 wt% carbon black shows 65.6 dB which is amazingly high for other reported values till date. This can be said that the prepared conducting foam is suitable alternative for low cost durable EMI shielding material.