Quantifying structural and electromagnetic interference (EMI) shielding properties of thermoplastic polyurethane–carbon nanofiber/magnetite nanocomposites

Abstract

In this study, mixed-structure carbon-magnetite nanocomposites were prepared by decorating of carbon nanofiber (CNF) surfaces with magnetite (Fe 3 O 4 ) nanoparticles synthesized via reflux method and characterized. The compositions of CNF-Fe 3 O 4 nanocomposites were varied using different amounts of CNF into the Fe 3 O 4 synthesis medium as 25/75, 50/50, and 75/25 (w/w). These nanocomposites were then used as functional fillers to prepare flexible, thermoplastic polyurethane (TPU)-based electromagnetic interference (EMI) shielding composites by solution mixing method. Structural features of fillers, morphological, and electromagnetic properties of flexible composites were studied. It was found that the magnetite nanoparticles with the average size of 8-10 nm were formed and successfully covered the oxidized CNF surfaces. It was also found that the resulting CNF-Fe 3 O 4 nanocomposites exhibited sufficiently high saturation magnetization (M s ) values compared to Fe 3 O 4 . These CNF-Fe 3 O 4 nanocomposites were embedded into TPU phase by employing the weight percent of 20 wt%. The flexible TPU-CNF-Fe 3 O 4 nanocomposite having the composition of 80-5-15 wt% showed the reflection loss (RL) value of -32 dB which signified that the composite material could absorb the 97 % of an incident electromagnetic wave at around 12.14 GHz.

Preparation of microcellular thermoplastic polyurethane (TPU) foam and its tensile property

“…Furthermore, the nonchemical crosslinked structure means that TPU is recyclable and can be reprocessed above the highest melting temperature using the traditional technique . Unique properties make TPU more promising in some applications such as supercapacitor , electromagnetic interference shielding , shape memory , automotive parts , and sensor . In terms of high price of TPU , it is necessary to reduce the cost, which can be effectively solved through the foaming process.…”

Magnetic foams from polyurethane and magnetite applied as attenuators of electromagnetic radiation in X band

“…Type of PU Reflectivity (dB) Reference PU/ Grafeno Flexible foam $ −15.0 Bernal 2012 [50] PU/ CNT Flexible foam $ − 17.0 Liu 2007 [51] PU/GO Flexible foam -20.0 Rohini 2017 [52] PU/GE (20% m/m in GE) Thermoplastic -20.0 Valentine 2015 [53] PU/NFC/Fe 3 O 4 Thermoplastic -32.0 Durmos 2016 [55] F5 (5%m/m in Fe 3 O 4 ) Rigid foam -34.41 This work…”

Investigation of the microwave attenuation performance and structure‐property relationship for graphite‐filled cyclo‐olefin copolymer composites

“…[ 21 ] However, a narrow effective absorption bandwidth is the main drawback of carbon‐filled polymer composites in RAM applications. [ 21 ] Different approaches have been developed in the literature to overcome this disadvantage, including preparation of magnetic particle‐coated hybrid carbon fillers, [ 26,27 ] design of multilayer structures, [ 28,29 ] and simultaneous use of carbon and magnetic fillers in a single polymer phase. [ 30 ]…”

“…[21] However, a narrow effective absorption bandwidth is the main drawback of carbon-filled polymer composites in RAM applications. [21] Different approaches have been developed in the literature to overcome this disadvantage, including preparation of magnetic particle-coated hybrid carbon fillers, [26,27] design of multilayer structures, [28,29] and simultaneous use of carbon and magnetic fillers in a single polymer phase. [30] Generally, the ability of carbon-filled polymeric composites to interact with electromagnetic waves is not only related to the intrinsic (ie, conductivity, complex permittivity, and permeability) properties of the fillers and polymers but also their physical and microstructural properties (ie, size, aspect ratio, dispersion, and orientation of filler particles).…”