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

Abstract

Abstract:The dielectric and electromagnetic interference (EMI) shielding properties of polycarbonate/graphene nanocomposites foamed using supercritical carbon dioxide were studied as a function of their cellular and composite morphology. Foamed polycarbonate filled with 0.5% (by weight) graphene exhibited enhanced EMI shielding effectiveness, which was found to depend on cellular and composite morphology in a complex manner.Foamed composites presented a maximum specific EMI shielding effectiveness of ~39 dB.cm 3 /g, which is approximately 35 times greater than that of unfoamed composite (1.1 dB.cm 3 /g). In addition, the relative permittivity was found to increase up to 3.25 times. The results suggest that graphene filled polymer foams can enhance the performance of electronic devices, opening up the possibility of using these materials in electronic applications.

Free volume correlation with electrical conductivity of polycarbonate/reduced graphene oxide nanocomposites studied by positron annihilation lifetime spectroscopy

“…Among these conductive fillers, graphene has recently gained importance due to its high aspect ratio, small size, and excellent electrical conductivity . Different methods have been used to fabricate graphene filled PC composites (PC/G) including solution mixing, melt intercalation, and in situ exfoliation . Kim and Macosko prepared PC reinforced with functionalized graphene sheets using melt compounding, and the seven orders of magnitude increase in electrical conductivity was obtained .…”

Mechanistic Insight into the Critical Concentration of Barium Hexaferrite and the Conductive Polymeric Phase with Respect to Synergistically Electromagnetic Interference (EMI) Shielding

“…In this connection, composites containing dielectric and magnetic lossy materials have received wide attention due to their high magnetic loss in the gigahertz frequency region . Various studies were carried out to enhance EMI shielding by different (magnetic and dielectric) particle‐polymer composites such as BaTiO 3 ‐Polyaniline(PANI), BaTiO 3 ‐Graphene, Fe 3 O 4 ‐PANI, Titania foam, polycarbonate‐graphene, CNT‐PANI, MWCNT with Fe 3 O 4 and TiO 2 ‐PANI nanocomposites. The M (magnetoplumbite)‐type hexaferrites (A 2+ Fe 3+ 12 O 19 , A=Ba, Pb and Sr), are potentially superior microwave absorbers because of their high magnetic anisotropy field, high saturation magnetization, high Curie temperature, excellent structural and chemical stability; and their natural ferromagnetic resonance occurs in the GHz frequency region .…”

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 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) . In a recent study, electrically conductive PC composites were prepared by blending thermally exfoliated graphene and p ‐phenylenediamine (PPD)–functionalized and reduced GO (GO‐PPD) with PC .…”

“…157 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). 158 In a recent study, electrically conductive PC composites were prepared by blending thermally exfoliated graphene and p-phenylenediamine (PPD)-functionalized and reduced GO (GO-PPD) with PC. 159 The PC/GO-PPD nanocomposites showed EC approximately 0.7 × 10 −1 S/m at 3 wt% GO-PPD.…”