Electromagnetic shielding effectiveness of polycarbonate/graphene nanocomposite foams processed in 2-steps with supercritical carbon dioxide

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

“…Just recently similar anisotropy has been discussed in composite foams prepared in 2 steps in which the foams did not present crystallinity [26]. It is possible to detect the distribution of structural heterogeneities in samples from 2D SAXS patterns by integrating the scattering intensity [37].…”

“…The maximum EMI shielding effectiveness was found to be ~15 dB (at 8.5 GHz) and it is equivalent to a power attenuation of the incident EM radiation by a factor of ~30, which corresponds to a transmission of ~3.3% [18]. This EMI SE values are slightly higher than PC/graphene foams with considerably lower relative density prepared by the 2-step method [26], in which larger cell sizes promoted higher EMI SE values. However in the composite foams prepared in 1-step, this behavior was not observed.…”

“…This method of lateral guidance is much less expensive than the use of magnets embedded along the length of traffic lanes [24]. Recently we prepared PC/graphene composite foams following a 2-step method [25] and later reported the EMI shielding behavior of these materials with low relative densities ranging from 0.14 to 0.28 where the main shielding mechanism exhibited was reflection [26].…”

A review on the mechanical, electrical and EMI shielding properties of carbon nanotubes and graphene reinforced polycarbonate nanocomposites

“…Gedler et al investigated the EMI shielding properties of foamed PC/graphene nanocomposites processed in 2 steps and even in a single step with scCO 2 (Table ). In 2‐step foaming method, maximum EMI SE (−14 dB) was achieved for foamed composite samples, which was 70 times higher than that of the unfoamed composite samples (−0.2 dB) . In 1‐step foaming method, composites presented a maximum specific EMI SE (−7 dB), which is approximately 35 times greater than that of unfoamed composite (−0.2 dB) .…”

Low density polycarbonate–graphene nanocomposite foams produced by supercritical carbon dioxide two-step foaming. Thermal stability

“…Recently we showed that a two-step foaming process based on the initial dissolution of scCO 2 and later foaming by heating could lead to the formation of PC-GnP foams with much lower relative densities (between 0.08 and 0.28) [20][21], indirectly resulting in even better graphene nanoplatelets dispersion, effectively enhancing the electromagnetic shielding properties of these foams [22]. However, no studies so far have thoroughly analyzed the thermal stability of low density PC-GnP nanocomposite foams, as density reduction could further enhance thermal stability.…”