Lightweight, multifunctional microcellular PMMA/Fe 3 O 4 @MWCNTs nanocomposite foams with efficient electromagnetic interference shielding

Zhang, Hongming; Zhang, Guangcheng; Li, Jiantong; Fan, Xun; Jing, Zhanxin; Li, Jianwei; Shi, Xuetao

doi:10.1016/j.compositesa.2017.05.009

Cited by 221 publications

(109 citation statements)

References 58 publications

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“…Neat PMMA is a homogeneous system in which the nucleation is generated by the thermodynamical instability. In contrast, the PMMA/MWCNT nanocomposite is a heterogeneous system in which the MWCNTs act as the heterogeneous nucleating agents to offer the nucleation sites . Nucleation for nanocomposites is much easier than that for neat PMMA because a smaller

Δ G_{crit}^{*}

is required at the interfaces between the PMMA matrix and the MWCNT .…”

Section: Resultsmentioning

confidence: 99%

“…Zeng et al fabricated a series of PMMA/CNT nanocomposite foams with a high tensile strength, but the foams' expansion ratio was only twofold. Zhang et al reported that MWCNTs modified by Fe 3 O 4 helped to increase the cell density and reduce the cell size of PMMA foams. Although the PMMA/Fe 3 O 4 @MWCNT foams exhibited an excellent electromagnetic interference (EMI) shielding performance, the maximum expansion ratio of the foams was only about fivefold.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming

Zhao

Wang

et al. 2019

Macro Materials & Eng

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Poly(methyl methacrylate) (PMMA) foams exhibit many advantages over the most popular polystyrene (PS) foams, which make them an ideal candidate for thermal insulation application. First, PMMA has lower carbon content, lower burning rate, smaller heat release rate, and lower smoke emission than PS. [7] So, PMMA foams need less flame retardants than PS foams when used as construction thermal insulation materials, which helps reduce the overall production costs and mitigate the greenhouse effect. Second, PMMA can strongly absorb infrared light in the wavelength range of 2.8-25 µm, [8] while PS can hardly absorb infrared light. Thus, the low-density PMMA foams are expected to block more thermal radiations than the PS foams with the same density. Third, PMMA has higher CO 2 solubility than PS because the carbonyl group in PMMA has stronger adsorption capacity for CO 2 than the benzene ring in PS. [9] The higher CO 2 solubility makes it much easier to prepare low-density PMMA foam, enhancing foam's thermal insulation. Carbon nanotubes (CNTs) with unique electrical, mechanical, and thermal properties have exhibited great value in designing electrical conductive composites, [10,11] electromagnetic interference shielding, [12,13] and energy harvesting materials. [14] These excellent properties of CNTs also make them ideal fillers to design polymer foams for some important reasons. First, CNTs are excellent heterogeneous nucleating agent to increase the cell density. Cell nucleation is more likely to occur at the interfaces between fillers and polymer matrix because of the relatively low free energy barrier for heterogeneous nucleation. [15][16][17] Due to their high aspect ratio and specific area, uniformly dispersed CNTs can offer much more interfaces as the heterogeneous nucleation sites than many other spherical (i.e., nano SiO 2 [18] ) or lamellar fillers (i.e., nano clay [19] ). Moreover, CNTs can endow the polymer foams with multifunctionality by offering the same advantages that they offer in the bulk while not decreasing foam's other properties. For example, CNTs are one kind of good wave-absorbing material that can be recognized as black bodies. In electromagnetic fields, CNTs can attenuate electromagnetic radiation by forming a conductive network (conductivity loss), [12,20] or by the polarization of CNT/polymer interfaces (dielectric loss), [21,22] or by scattering and multiple Polymer Nanocomposite Foaming behavior of poly(methyl methacrylate) (PMMA)/multi-walled carbon nanotubes (MWCNTs) nanocomposites and thermally-insulating, electrical, and mechanical properties of the nanocomposite foams are investigated. PMMA/MWCNT nanocomposites containing various amounts of MWCNTs are first prepared by combining solution and melt blending methods, and then foamed using CO 2 . The foaming temperature and MWCNT content are varied for regulating the structure of PMMA/MWCNT nanocomposite foams. The electrical conductivity measurement results show that MWCNTs have little effect on the electrical conductivity of foams with l...

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Δ G_{crit}^{*}

is required at the interfaces between the PMMA matrix and the MWCNT .…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming

Zhao

Wang

et al. 2019

Macro Materials & Eng

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“…Use of magnetic materials for EM shielding and EM wave absorption has been limited. Magham et al developed Z‐type hexaferrites.…”

Section: Selective Overview and Materials Selectionmentioning

confidence: 99%

“…This mechanism requires the presence of a large surface area or interface area in the shield. An example of a shield with a large surface area is a porous or foam material . Another example of a shield with a large interface area is a polymer material containing filler characterized by a large surface area.…”

Section: Selective Overview and Materials Selectionmentioning

confidence: 99%

Polymer Composites for Flexible Electromagnetic Shields

Sahu¹,

De²

2018

Macromolecular Symposia

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Harmful electromagnetic (EM) interference (EMI) to living beings and various sensitive instruments by EM radiations from electronic and electrical gadgets and mobile towers is increasing rapidly. It inflicts illness, and presumably cancerous growth in human cells. EMI is minimized by wrapping the receiver and/or the emitter gaplessly by an efficient EM shielding sheet. Compared to the widely used and classical metallic shields, 2nd generation polymer composite EMI shields are lighter and more flexible. Conventional polymer composites use conducting polymers and metallic/carbon powders that have conducting electrons to reflect EM waves away. A polymeric binder, curing overnight to a soft and flexible sheet, has presently been selected for making the polymeric composites. We test EM shielding by certain non‐metallic composites. We review results for composites with fine metallic fibers (copper and brass turnings, available as waste from mechanical workshops) or conducting forms of cadmium oxide or ferroelectric materials (PbNb2O6 [o‐PN] & BaTiO3 [BT]) or their mixtures (52 samples). Small pieces of these cloth‐like polymeric sheets have been characterized in a Vector Network Analyzer (VNA), by measuring input power (Pin), the reflected power (Prefl), and the transmitted power (Pout), over five frequency bands in 700 MHz to 40 GHz range to find Shielding Effectiveness (SE) = 10 log (Pout/Pin) and Reflection Effectiveness = 10 log (Prefl/Pin). Success of o‐PN, BT, conducting (fired) Cd‐O, metallic turnings and their combinations has been discussed, highlighting some new observations. Composites, developed in this work, include EMI Shielding materials and potential Radar Absorption Materials.

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“…By the rational selection of llers, it is possible to control the basic properties of the material, [1][2][3][4][5][6] such as melting temperature, magnetic properties, charge capacity, and color, without changing the chemical composition. Performances improvement and optimization based on micro/nano llers promise extensive applications in many elds such as mechanical reinforcement, 7,8 lightweight components, 9 sensors, 10,11 and etc. The llers can be three-dimensional framework, two-dimensional, one-dimensional and even zerodimensional materials.…”

Section: Introductionmentioning

confidence: 99%

Formation of highly ordered micro fillers in polymeric matrix by electro-field-assisted aligning

et al. 2019

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Lightweight, multifunctional microcellular PMMA/Fe 3 O 4 @MWCNTs nanocomposite foams with efficient electromagnetic interference shielding

Cited by 221 publications

References 58 publications

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming

Polymer Composites for Flexible Electromagnetic Shields

Formation of highly ordered micro fillers in polymeric matrix by electro-field-assisted aligning

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Lightweight, multifunctional microcellular PMMA/Fe 3 O 4 @MWCNTs nanocomposite foams with efficient electromagnetic interference shielding

Cited by 221 publications

References 58 publications

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO2 Foaming

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO2 Foaming

Polymer Composites for Flexible Electromagnetic Shields

Formation of highly ordered micro fillers in polymeric matrix by electro-field-assisted aligning

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Product

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Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming

Thermal‐Insulation, Electrical, and Mechanical Properties of Highly‐Expanded PMMA/MWCNT Nanocomposite Foams Fabricated by Supercritical CO₂ Foaming