Electromagnetic Characterization of Psu/Carbon Black Multifunctional Composites

Abstract

Multifunctional composites are materials capable of combining structural properties with other properties, such as electrical or thermal conductivity, electromagnetic shielding capacity, among others. With the exponential increase in the use of electrical and electronic devices, a specific type of environmental pollution, electromagnetic interference (EMI), has arisen due to the spurious radiation emitted by such devices. Thus, this work proposes the development of a multifunctional composite material based on polysulfone (PSU) and carbon black (CB) and its electromagnetic characterization in the X-band frequency, between 8.2 and 12.4 GHz, widely used in communication and navigation system. The composite materials were produced with high-performance engineering thermoplastic polymer PSU, organic solvent Dichloromethane and two varieties of additive CB. The composite was processed through hot compression molding of films prepared from PSU polymer solutions with the dispersion of the CB additive by means of an ultrasonic tip. The composite processing cycle was obtained through the thermal characterization of the films by differential scanning calorimetry (DSC) and the electromagnetic characterization was conducted with a vector network analyzer (VNA) and rectangular waveguide. With the determination of the scattering parameters (Transmission and Reflection) it was possible to evaluate the interaction of the electromagnetic waves with the composites and quantify the portions of energy reflected, transmitted and absorbed. The composite presented a favorable behavior for electromagnetic shielding, with average reflection values greater than 65%, absorption greater than 21% and transmission lower than 11%.