Enhanced electrical conductivity and EMI shielding performance through cell size-induced CNS alignment in PP/CNS foam

Wu, Minghui; Ren, Qian; Gao, Peng; Ma, Wenyu; Shen, Bin; Wang, Long; Zheng, Wenge; Cui, Ping; Yi, Xiaosu

doi:10.1016/j.coco.2023.101716

Cited by 7 publications

(2 citation statements)

References 37 publications

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“…Some researchers have even further extended this layered, gradient-like concept, combining conductive foamed layers that are based on a polymer nanocomposite foam, with layers formed by different materials, such as aluminum, knitted fabric layers, etc., thus endowing the sandwich-like materials with excellent EMI shielding [51]. Taking advantage of the fact that the generation of a controlled and particular cellular structure during foaming may reduce the actual conductive paths between conductive particles pre-dispersed throughout the polymer-based matrix before foaming due to an excluded volume effect and even promote the redistribution and alignment of the particles, Wu and co-workers [21] were able to prepare PP-CNT composite foams with enhanced EMI shielding efficiencies (reaching values of almost 60 dB) using a core-back foaming injection molding process, as foaming enabled the creation of cellular structures with big cells, which promoted the formation of a more effective path comprising aligned conductive particles. Yang et al [22] had already used a similar strategy to prepare highly conductive polymerbased composites at extremely low rGO percolation thresholds (0.055 vol%).…”

Section: Selective Distribution Of Conductive Nanofillersmentioning

confidence: 99%

Recent Trends in Polymeric Foams and Porous Structures for Electromagnetic Interference Shielding Applications

Antunes

2024

Polymers

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Polymer-based (nano)composite foams containing conductive (nano)fillers limit electromagnetic interference (EMI) pollution, and have been shown to act as good shielding materials in electronic devices. However, due to their high (micro)structural complexity, there is still a great deal to learn about the shielding mechanisms in these materials; understanding this is necessary to study the relationship between the properties of the microstructure and the porous structure, especially their EMI shielding efficiency (EMI SE). Targeting and controlling the electrical conductivity through a controlled distribution of conductive nanofillers are two of the main objectives when combining foaming with the addition of nanofillers; to achieve this, both single or combined nanofillers (nanohybrids) are used (as there is a direct relationship between electrical conductivity and EMI SE), as are the main shielding mechanisms working on the foams (which are expected to be absorption-dominated). The present review considers the most significant developments over the last three years concerning polymer-based foams containing conductive nanofillers, especially carbon-based nanofillers, as well as other porous structures created using new technologies such as 3D printing for EMI shielding applications. It starts by detailing the microcellular foaming strategy, which develops polymer foams with enhanced EMI shielding, and it particularly focuses on technologies using supercritical CO2 (sCO2). It also notes the use of polymer foams as templates to prepare carbon foams with high EMI shielding performances for high temperature applications, as well as a recent strategy which combines different functional (nano)fillers to create nanohybrids. This review also explains the control and selective distribution of the nanofillers, which favor an effective conductive network formation, which thus promotes the enhancement of the EMI SE. The recent use of computational approaches to tailor the EMI shielding properties are given, as are new possibilities for creating components with varied porous structures using the abovementioned materials and 3D printing. Finally, future perspectives are discussed.

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Section: Selective Distribution Of Conductive Nanofillersmentioning

confidence: 99%

Recent Trends in Polymeric Foams and Porous Structures for Electromagnetic Interference Shielding Applications

Antunes

2024

Polymers

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show abstract

“…Taking advantage of the fact that the generation of a controlled and particular cellular structure during foaming may reduce the actual conductive paths between conductive particles pre-dispersed throughout the polymer-based matrix before foaming due to an excluded volume effect and even promote the redistribution and alignment of the particles, Wu and co-workers [42] were able to prepare PP-CNT composite foams with enhanced EMI shielding efficiencies (reaching values of almost 60 dB) using a core-back foaming injection molding process, as foaming enabled to create cellular structures with big cells, which promoted the formation of a more effective path of aligned conductive particles. Yang et al [43] had already used a similar strategy to prepare highly conductive polymer-based composites at extremely low rGO percolation thresholds (0.055 vol%).…”

Section: Selective Distribution Of Conductive Nanofillersmentioning

confidence: 99%

Recent Trends on Polymeric Foams and Porous Structures for Emi Shielding Applications

Antunes

2023

Preprint

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Polymer-based (nano)composite foams, especially those having a microcellular structure, containing suitable conductive (nano)fillers, have been shown to act as good shielding materials, hence coming as promising to act as shields in electronic devices, limiting/avoiding electromagnetic interference (EMI) pollution. Nevertheless, due to their high (micro)structural complexity, related to their multiphase nature, there is still a lot of unawareness behind the shielding mechanisms acting in these materials, coming as a necessity to study their microstructure-cellular/porous structure-properties relations, especially in terms of their electrical conductivity and EMI shielding efficiency (EMI SE). To target and control the electrical conductivity through a controlled distribution/dispersion of conductive nanofillers, single or combined (nanohybrids), as there is a direct relation between electrical conductivity and EMI SE, as well as the main EMI shielding mechanisms working on the developed microcellular structure of the foams, which are expected to be absorption-dominated or absorption/multiple reflection-based, are two of the main objectives when combining polymer foaming with the addition of conductive nanofillers. The present review work considers the recent developments and trends on polymer-based foams containing conductive nanofillers, especially carbon-based such as carbon nanotubes or graphene-based materials, as well as similar porous structures created using trending technologies such as 3D printing, for EMI shielding applications. It is divided in different sections, starting with the strategy of microcellular foaming to develop polymer-based foams with enhanced EMI shielding characteristics, especially focusing on technologies and methods using supercritical CO2 (sCO2); continuing with the use of polymer foams as templates to synthesize carbon foams with improved EMI shielding performance for high use temperature applications; the recent strategy of combining different functional (nano)fillers to create hybrid nanofillers/nanohybrids to be used at lower amounts as conductive fillers in polymer foams; the control and selective distribution of the nanofillers in terms of favoring the formation of a more effective conductive network and hence promote the enhancement of the EMI SE; the very recent use of computational approaches to tailor the EMI shielding properties of composite foams; and the very trending possibility of creating cellular components with varied porous structures from these materials using 3D printing; to finish, some future perspectives are discussed.

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Structural Design of Multifunctional PET Non‐woven Fabric with Porous Dual‐Network for Infrared Stealth, Flame Retardant, and Electromagnetic Interference Shielding

Bai,

Feng,

Wang

et al. 2024

Adv Eng Mater

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With rapid advances in electronic and communication technology, electromagnetic interference and other problems are becoming increasingly prominent. Thus, electromagnetic interference shielding materials have recently garnered extensive attention. In this study, a multi‐walled carbon nanotube/polyurethane/non‐woven electromagnetic shielding material (CPNW) is developed using impregnation and nonsolvent‐induced‐phase separation techniques. Utilizing a three‐dimensional nonwoven network as the substrate, the “nonwoven fabric‐polyurethane‐carbon nanotube” composite is impregnated and cured via the non‐solvent‐induced‐phase separation method, resulting in a distinctive porous dual‐network structure that ensures robust interfacial bonding between carbon nanotubes, nonwoven fabric, and polyurethane. At a carbon nanotube content of 10% (based on the mass of nonwoven fabric), CPNW exhibited an electromagnetic interference shielding effectiveness of 28.8 dB, a thermal conductivity of 0.127 W m−1 K−1, and a burning time of 1 min and 15 s, demonstrating outstanding electromagnetic shielding, flame retardant, and infrared stealth capabilities. Overall, this study laid a theoretical groundwork for the development of multifunctional non‐woven electromagnetic shielding materials with widespread application potential in aerospace, military, artificial intelligence, and wearable electronics.

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Enhanced electrical conductivity and EMI shielding performance through cell size-induced CNS alignment in PP/CNS foam

Cited by 7 publications

References 37 publications

Recent Trends in Polymeric Foams and Porous Structures for Electromagnetic Interference Shielding Applications

Recent Trends in Polymeric Foams and Porous Structures for Electromagnetic Interference Shielding Applications

Recent Trends on Polymeric Foams and Porous Structures for Emi Shielding Applications

Structural Design of Multifunctional PET Non‐woven Fabric with Porous Dual‐Network for Infrared Stealth, Flame Retardant, and Electromagnetic Interference Shielding

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