Reflection and absorption contributions to the electromagnetic interference shielding of single-walled carbon nanotube/polyurethane composites

Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

“…This behavior agrees with previously reported literature findings: EMI shielding (both reflection and absorption contributions) was found to increase with increasing conductive filler concentration at low concentrations. On the other hand, at high conductive filler concentrations, the absorption contribution was found to increase while the reflection contribution was fund to decrease [60]. In the current study, the observed increase in dielectric constant during foaming could be related to the enhanced dispersion of graphene nanoplatelets taking place during foaming, as previously discussed, rather than to the addition of high amount of filler.…”

“…However in the composite foams prepared in 1-step, this behavior was not observed. It is well known that the addition of fillers will increase the dielectric permittivity [60][61]. It is possible to state that the enhanced EMI SE is strongly related to the improvement observed in dielectric constant (see Figures 6 and 7).…”

“…In foams, reflection is related to impedance mismatch between air (in the cells) and absorber (matrix material) [15,60,62], absorption is related to energy dissipation in the absorber, and multiple reflections are considered to be due to scattering effect of inhomogeneities that might exist within the material [18]. To understand which mechanisms are operational in the current work, reflection contribution was calculated for each sample and is presented in Figure 8 as a function of relative density.…”

Foam injection molding of polypropylene/stainless steel fiber composites for efficient EMI shielding

“…Conductive polymer composites (CPCs) are becoming promising candidates to be employed as EMI shields as they offer light weight, low cost, good processability, and high resistance to corrosion and various CPCs containing micro-sized [4][5][6][7][8][9], and nano-sized [10][11][12][13][14][15] fillers have been developed for EMI shielding applications. However, CPCs are not yet very successful in replacing metal-based shields due to the required high filler loading.…”

Avaliação das propriedades dinâmico mecânicas e reológicas de compositos nanoestruturados de PPS/MWCNT

“…No entanto, um dos obstáculos para o uso em escala industrial dessas nanoestruturas está no elevado custo dos nanotubos de carbono quando comparado ao valor da matriz polimérica, ou mesmo a outros tipos de reforços. Além disso, a otimização do processo de dispersão dos nanotubos na matriz polimérica ainda é o principal desafio para produção em larga escala dos materiais nanoestruturados [5][6][7][8][9][10][11] . …”