Shielding effectiveness of carbon-filled polypropylene composites

Abstract

Adding conductive carbon fillers to insulating thermoplastic resins increases composite shielding effectiveness. In this study, varying amounts of three different carbons (carbon black, synthetic graphite particles, and carbon nanotubes) were added to polypropylene resin. The resulting single filler composites were tested for shielding effectiveness. The effects of single fillers and combinations of two different carbon fillers were studied via a factorial design. At the highest single filler loadings, the following shielding effectiveness results were obtained at 800 MHz: 23.4 dB for 10 wt% carbon black/polypropylene, 34.7 dB for 70 wt% synthetic graphite/polypropylene, and 45.9 dB for 15 wt% carbon nanotubes/polypropylene. The factorial results indicated that for the composites containing only single fillers, carbon nanotubes, carbon black, and synthetic graphite cause a statistically significant increase in composite shielding effectiveness. All composites containing combinations of two different fillers had a statistically significant effect which increased shielding effectiveness. The shielding effectiveness values for the 2.5 wt% carbon black/65 wt% synthetic graphite/polypropylene and 65 wt% synthetic graphite/6 wt% carbon nanotubes/polypropylene composites are >60 dB, which is higher than that of many metals.

Effects of carbon fiber modification with multiwall CNT on the electrical conductivity and EMI shielding effectiveness of polycarbonate/carbon fiber/CNT composites

“…Table shows a comparison of EMI SE values of the PC with different carbon filler species and contents. Table also shows the EMI SE values of the PP/carbon black composite, polystyrene (PS)/graphite composite, epoxy/single wall CNT composite, and polyamide‐6 (PA‐6)/CF composite . From Table , the EMI SE values ranged from 14 to 26 dB with the carbon filler content from 3.0 to 15.0 wt %, and the EMI SE of the composite increased with the increase of filler proportion.…”

Polypropylene Carbon Nanotubes Nanocomposites: Combined Influence of Block Copolymer Compatibilizer and Melt Annealing on Electrical Properties

“…However these performances result from a combination of reflection and absorption rather than pure absorption. Regarding polypropylene composites interesting properties were observed at 800 MHz in [45]. In [46] up to 15 dB shielding effectiveness was obtained with polypropylene loaded with carbon fibers.…”

Effects of hybrid fillers on the electrical conductivity, EMI shielding effectiveness, and flame retardancy of PBT and PolyASA composites with carbon fiber and MWCNT

“…In the studies of the PBT/ CF (30 wt %) composite, Hwang reported the EMI SE of 11.1 dB at the frequency of 1.1 GHz . In the polypropylene (PP)/carbon black (CB) (10 wt %) composite by King et al ., they showed the EMI SE of 23.4 dB at the frequency of 0.8 GHz. Maiti and Khatus reported the EMI SE of 21.6 dB for the polycarbonate (PC)/graphene (2.4 wt %)/MWCNT (1.6 wt %) composite.…”