Ultralow Dielectric Constant Polyarylene Ether Nitrile/Polyhedral Oligomeric Silsesquioxanes Foams with High Thermal Stabilities and Excellent Mechanical Properties Prepared by Supercritical CO<sub>2</sub>

Shi, Shuyuan; Liao, Xia; Tang, Wenchao; Song, Pengwei; Zou, Fangfang; Fan, Zuo-Ze; Guo, Fengjiao; Li, Guangxian

doi:10.1002/adem.202100874

Cited by 18 publications

(10 citation statements)

References 66 publications

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“…This low dielectric property is mainly attributed to the foam's high porosity and the quite low dielectric nature of the dispersedly filled BNNS fillers within the BSFs, which make a synergistic effect to lead to the ultralow DC. These resulting DCs are significantly lower than those of the PDMS-based or other types of composite systems of polymeric foam filled with other inorganic fillers, such as 2.08−3.48 for BN/PI, 23 1.83 for PEN/POSS, 24 1.42 for F/30BN, 25 and 1.25 for PEN 26 (Table S3 in SI). These are the main reasons that caused BSF's low DLT performances: First, the inherent insulation characteristics of BNNSs could well suppress an increase in BSF's conductive loss.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

Highly Multifunctional Performances of Boron Nitride Nanosheets/Polydimethylsiloxane Composite Foams

Qiao

Gao

et al. 2023

ACS Appl. Mater. Interfaces

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Although this kind of hexagonal boron nitride (h-BN)-filled polydimethylsiloxane (PDMS) multifunctional composite foam has been greatly expected, its development is still relatively slow as a result of the limitation of synthetic challenge. In this work, a new foaming process of BNNSs-PDMS, alcohol, and water three-phase emulsion system is employed to synthesize a series of high-quality BNNSs/PDMS composite foams (BSFs) filled with highly functional and uniformly distributed BNNSs. As a result of well-bonded interfaces between the BNNSs and PDMS, enhanced multiple functions of BSFs appeared. The BSFs can show complete resilience at a compressive strain of 90% and only 3.99% irreversible deformation after 100,000 compressing–releasing hyperelastic cycles at a strain of 60%. On the basis of their outstanding shape-memory properties, the maximum voltage value of compression-driven piezo-triboelectric (CDPT) responses of the BSFs is up to ∼20 V. Depending on the remarkable super-elastic and CDPT performances, the BSFs can be used for sensitive sensing of temperature difference and electromechanical responses. Also, in the range of 12–40 GHz, the BSF materials display ultralow dielectric constants between 1.1 and 1.4 with proper dielectric loss tangent values of <0.3 and exhibit an enhanced and broadened sound adsorption capacity ranging from 500 to 6500 Hz. Although BSFs have high porosities of >65%, their thermal conductivities can still reach up to 0.407 ± 0.039 W m–1 K–1. Moreover, the BSF materials display favorable thermal stability, obviously reduced coefficient of thermal expansion, and good flame retardancy. All of these properties render the BSFs as a new category of excellent multifunctional material.

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Section: ■ Results and Discussionmentioning

confidence: 96%

Highly Multifunctional Performances of Boron Nitride Nanosheets/Polydimethylsiloxane Composite Foams

Qiao

Gao

et al. 2023

ACS Appl. Mater. Interfaces

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“…This can be attributed to the ultrahigh melting point of PPTA molecules, which the PPTA molecules decompose before melting. As the low dielectric constant/loss, excellent mechanical properties, and high thermal stability are all important factors that need to be considered for evaluating a dielectric material, the nanoporous ANF aerogel films exhibit superior comprehensive performance, which outperforms the vast majority of dielectric materials (Figure e). − …”

Section: Resultsmentioning

confidence: 99%

Ambient Drying Route to Aramid Nanofiber Aerogels with High Mechanical Properties for Low-k Dielectrics

Liu

Robertson

Qiang

et al. 2022

ACS Appl. Polym. Mater.

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Polymeric aerogels with low dielectric constant (low-k) are an important material solution for applications in high-frequency terminal electronic devices. However, most aerogels are prepared using high-cost supercritical drying or freeze-drying methods and typically exhibit poor mechanical properties and low thermal stability, which limits their use in practical applications. Here, we report the fabrication of aerogels with layered structure and hierarchical nanopores based on aramid nanofibers (ANFs), using a vacuum-assisted filtration method followed by low-cost ambient drying. The porosity of the ANF aerogels can be controlled from 38 to 79% by rationally selecting solvents with different surface tension for solvent exchange, tuning the affinity between solvents and ANF skeletons as well as controlling the solvent evaporation rate during the ambient drying process. The ANF aerogels have an ultralow and tunable dielectric constant as low as 1.56 while exhibiting a low dielectric loss between 0.0040 to 0.0055 at 1 MHz. The advantageous low-k property can be preserved at high temperatures up to 300 °C, and an inherent flame retardancy is achieved due to the rigid and all-aromatic backbone structure of poly(p-phenylene terephthalamide). Moreover, the nanoporous ANF layers with relatively lower porosity compared with the overall porosity of the aerogel provide strong mechanical strength and modulus, while the presence of larger nanopores from the interspacing of ANF layers ensures a high porosity for the entire aerogel, which endows the aerogel film with superior tensile strength and modulus compared with their conventional counterparts containing homogeneous porous structures. Collectively, these ANF aerogels exhibit low-k, outstanding mechanical properties, high thermal stability, and inherent flame retardancy, enabling them to become very promising next-generation dielectric materials.

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“…It should be noted that materials with a large number of air-filled cavities and cells in its volume have lower values of dielectric permittivity compared to similar close-packed matrices. Classical examples are porous-cellular (foam plastics [ 72 , 73 ], spheroplastics [ 74 ]), and porous-fibrous (non-woven fabrics [ 75 , 76 ] and mats [ 77 ]) materials.…”

Section: Radio-absorbing Materials and Technologies For Their Productionmentioning

confidence: 99%

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility

et al. 2022

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Recently, designers of electronic equipment have paid special attention to the issue of electromagnetic compatibility (EMC) of devices with their own components and assemblies. This is due to the high sensitivity of semiconductor microcircuits to electromagnetic interference. This interference can be caused either by natural phenomena, such as lightning strikes, or by technical processes, such as transients in circuits during fast periodic or random switching. Either way, interference implies a sudden change in voltage or current in a circuit, which is undesirable, whether it propagates along a cable or is transmitted as an electromagnetic wave. The purpose of this article is to review the works devoted to the development, creation, and investigation of modern polymeric nanocomposite materials used for shielding electromagnetic radiation and their effective application for solving problems of electromagnetic compatibility. Additionally, the approach to design EMI shielding complex media with predetermined parameters based on investigation of various properties of possible components is shown. In the review, all polymer composites are classified according to the type of filler. The issues of the interaction of a polymer with conductive fillers, the influence of the concentration of fillers and their location inside the matrix, and the structure of the nanocomposite on the mechanisms of electromagnetic interaction are considered. Particular attention is paid to a new generation of nanocomposite materials with widely adjustable electrical and magnetic properties. A wide class of modern filled polymeric materials with dielectric and magneto-dielectric losses is considered. These materials make it possible to create effective absorbers of electromagnetic waves that provide a low level of reflection coefficient in the microwave range. The model mechanisms for shielding electromagnetic radiation are considered in the paper. A detailed review of the electro-physical properties of polymer nanocomposites is provided. Multilayer electrodynamic media containing combinations of layers of filled polymer composite materials with nanoparticles of different compositions and manufactured using a single technology will make it possible to create electrodynamic media and coatings with the required electro-physical characteristics of absorption, transmission, and reflection. Within the framework of the two-layer coating model, the difference in the effects of the interaction of electromagnetic radiation with conductive layers located on a dielectric and metal substrate is demonstrated. It is shown that in order to achieve optimal (maximum) values of reflection and absorption of electromagnetic radiation in the appropriate frequency range, it is necessary to fit the appropriate layer thicknesses, specific conductivity, and permittivity. Such approach allows designers to create new shielding materials that can effectively vary the shielding, absorbing, and matching characteristics of coatings over a wide frequency band. In general, it can be said that the development of innovative polymer composite materials for shielding electronic devices from electromagnetic interference and excessive electromagnetic background is still an important task. Its solution will ensure the safe and uninterrupted operation of modern digital electronics and can be used for other applications.

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Ultralow Dielectric Constant Polyarylene Ether Nitrile/Polyhedral Oligomeric Silsesquioxanes Foams with High Thermal Stabilities and Excellent Mechanical Properties Prepared by Supercritical CO₂

Cited by 18 publications

References 66 publications

Highly Multifunctional Performances of Boron Nitride Nanosheets/Polydimethylsiloxane Composite Foams

Highly Multifunctional Performances of Boron Nitride Nanosheets/Polydimethylsiloxane Composite Foams

Ambient Drying Route to Aramid Nanofiber Aerogels with High Mechanical Properties for Low-k Dielectrics

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility

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Ultralow Dielectric Constant Polyarylene Ether Nitrile/Polyhedral Oligomeric Silsesquioxanes Foams with High Thermal Stabilities and Excellent Mechanical Properties Prepared by Supercritical CO2

Cited by 18 publications

References 66 publications

Highly Multifunctional Performances of Boron Nitride Nanosheets/Polydimethylsiloxane Composite Foams

Highly Multifunctional Performances of Boron Nitride Nanosheets/Polydimethylsiloxane Composite Foams

Ambient Drying Route to Aramid Nanofiber Aerogels with High Mechanical Properties for Low-k Dielectrics

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility

Contact Info

Product

Resources

About

Ultralow Dielectric Constant Polyarylene Ether Nitrile/Polyhedral Oligomeric Silsesquioxanes Foams with High Thermal Stabilities and Excellent Mechanical Properties Prepared by Supercritical CO₂