A Comparative Study of Multiwalled Carbon Nanotube Based Polystyrene and Toughened Polycarbonate Nanocomposites

The broad developments of electronic systems and telecommunications has led to a novel type of pollution i.e. electromagnetic interference (EMI). EMI has appeared as a major problem, which not only affecting the proper working of electronic devices but as well as causing harmful effects to the health of human beings [1,2]. Generally, mobile phone, radar, radio transceivers, microwave oven, and various electronic devices are the main causes of EMI [3,4]. The long time exposure of EM waves have also been recognized as strong cancer-causing agent [5]. Therefore, appropriate shield is required to reduce the effect of EM waves. Generally, electrically conductive or magnetic filler are used as a EMI shielding material, because these materials have capability to interact with coupled electric and magnetic fields of the incident EM waves [6,7]. Metals and metal loaded composites have been widely used as EMI shielding materials, but these materials have disadvantages such as high density, corrosion prone, inconvenient processing etc. which limits their practical applicability. As compare to the metals, carbon nanomaterials have appeared as promising alternative conductive filler for production of EMI shield [6,8,9]. Nowadays, the use of carbon nanotubes (CNTs), having ultra-high modulus and strength, good thermal and electrical properties, as filler in polymer nanocomposites prepare material with lower filler loadings having improved electrical and EMI shielding properties [10-15]. As reported in literature, mechanical strength, electrical conductivity or thermal properties and EMI shielding effectiveness of the polymer nanocomposites are affected by different factors such as the aspect ratio, dispersion, processing methods, treatment methods, and loading of CNTs [16]. Li et al. [15] studied the conductivity and EMI SE of epoxy/ SWCNT nanocomposites filled with SWCNTs having different aspect ratios. The maximum EMI shielding effectiveness has been reported for epoxy/SWCNT composites having 15wt% SWCNTslong (SE ∼49dB and 15-20dB obtained at 10MHz and in the 500MHz to 1.5GHz range respectively). In another study, Gupta et al. [17] reported EMI shielding properties (in Ku-band) of poly (trimethylene terephthalate) (PTT)/MWCNT nanocomposites. Electrical percolation of composites has been reported at 1wt% loading of MWCNT and SE of 36-42dB reported at 10wt% loading of MWCNT. Bai et al. [18] described the effect of nanotube aspect ratio on the electrical properties and mechanical strength of the