Hybrid Composites Based on Thermoplastic Polyurethane With a Mixture of Carbon Nanotubes and Carbon Black Modified With Polypyrrole for Electromagnetic Shielding

Abstract

Hybrid conducting composites comprising thermoplastic polyurethane (TPU) and mixtures of carbon black modified with polypyrrole (CB-PPy) and carbon nanotubes (CNT) were prepared by melt mixing process. The electrical conductivity, rheological properties and electromagnetic shielding effectiveness (EMI SE) of TPU/CB-PPy and TPU/CNT composites were also investigated those results observed for TPU/CB-PPy/CNT hybrid composites. TPU/CNT composites show a very sharp insulator-conductor transition and the electrical percolation threshold was about 1 wt% of CNT, which was lower than that found for TPU/CB-PPy (7 wt%). Moreover, EMI SE values of TPU/CNT composites were higher than those for TPU/CB-PPy due to the denser CNT conductive pathway into TPU matrix. In order to achieve the highest electrical conductivity and EMI SE values, mixtures of CB-PPy/CNT were added in the composites in different mass fractions. In fact, the electrical conductivity values increased by combining CB-PPy and CNT, resulting in hybrid composites of TPU/CB-PPy/CNT with higher EMI SE values when compared to TPU/CB-PPy composites. The present study demonstrates the potential use of hybrid polymer composites containing 5 or 8 wt% of CB-PPy/CNT at specific CB-PPy/CNT ratios with good processabilty and EMI SE values as high as −20 dB indicating the potential use of these materials for electromagnetic shielding application in the X-band frequency region.

Melt Spinning of Highly Stretchable, Electrically Conductive Filament Yarns

“…The compounding of CNTs and TPU created a percolative system [ 44 , 45 ] with a percolation threshold between 3 and 4 wt.% CNT. The lowest achieved specific resistance was 110 ± 39 Ωcm.…”

Trends in reinforced composite design for ionizing radiation shielding applications: a review

“…Nanofillers are frequently added to improve electrical properties, radiation shielding capacities, thermal conductivity and overall functionality of the hybrid composites. Bertolini et al [98] examined hybrid composites based on thermoplastic polyurethane with a mixture of carbon nanotubes and carbon black modified with polypyrrole for electromagnetic shielding purposes. Authors found that addition of carbon nanotubes and carbon black significantly improved the electrical conductivity, radiation shielding and rheological properties.…”

Excellent electromagnetic interference shielding performance of polypropylene/carbon fiber/multiwalled carbon nanotube nanocomposites

“…Arjmand et al 27 studied the comparison of nanotube/polystyrene composites for electromagnetic properties prepared via injection molding and compression molding and found the EMI SE of the compression‐molded samples was 30 dB at 20 wt% filler loading. Bertolini et al 28 achieved 20 dB EMI SE at 8 wt% of a modified carbon black with polypyrrole and carbon nanotubes prepared by the melt mixing process. Table 1 shows the reported research for EMI shielding using polypropylene as a matrix.…”