Radio Frequency Heating Response of Polyacrylonitrile (PAN) Films and Nanofiber Mats

Patil, Nutan; Oh, Ju Hyun; Khatri, Sumit; Saed, Mohammed A.; Naraghi, Mohammad; Green, Micah J.

doi:10.1021/acsapm.1c00319

Cited by 7 publications

(3 citation statements)

References 30 publications

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“…Specially, reaction-vessel materials including quartz, borosilicate and Teflon are nearly transparent to microwaves due to ultra-low tan δ values (close to 0). In some cases, strong microwave absorbers like metal pieces [57], carbon nanomaterials [58], conducting polymers [59] and silicon carbide boards [60] can act as heat susceptors or reaction triggers when coated at vessels or substrates. It is worthy of note that materials' dielectric properties are frequency-dependent.…”

Section: Principles Of Materials Selection For Ideal Microwave Heatingmentioning

confidence: 99%

Recent progress in microwave-assisted preparations of 2D materials and catalysis applications

Wang¹,

Wu²,

Kondo³

et al. 2022

Nanotechnology

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On the urgency of metal-free catalysts, two-dimensional materials (2DMs) have caused extensive researches because of distinctive optical and electronic properties. In the last decade, microwave methods have emerged in rapid and effective preparations of 2DMs for catalysis. Microwave heating offers several advantages namely direct, fast, selective heating and uniform reaction temperature compared to conventional heating methods, thus bringing about high-yield and high-purity products in minutes or even seconds. This review summarizes recent advances in microwave-assisted preparations of 2DMs-based catalysts and their state-of-the-art catalytic performances. Microwave heating mechanisms are briefly introduced mainly focusing on microwave-matter interactions, which can guide the choice of precursors, liquid media, substrates, auxiliaries and experiment parameters during microwave radiation. We especially provide a detailed insight into various microwave-assisted procedures, classified as exfoliation, synthesis, doping, modification and construction towards different 2DMs nanomaterials. We also discuss how microwave affects the synthetic composition and microstructure of 2DMs-based catalysts, thereby deeply influencing their optical and electronic properties and the catalytic performances. Finally, advantages, challenges and prospects of microwave-assisted approaches for 2DMs nanomaterials are summarized to inspire the effective and large-scale fabrication of novel 2DMs-based catalysts.

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Section: Principles Of Materials Selection For Ideal Microwave Heatingmentioning

confidence: 99%

Recent progress in microwave-assisted preparations of 2D materials and catalysis applications

Wang¹,

Wu²,

Kondo³

et al. 2022

Nanotechnology

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“…The differences in thermal physical interactions in the radial direction of the fibers result in changes in the composition and structural transformation. However, the fibers retain and further develop the radial structural differences formed in the early stage 4–6 …”

Section: Introductionmentioning

confidence: 99%

Effect of heat treatment on the radial structure of coaxial polyacrylonitrile/mesophase pitch composite fiber

Zhang,

Zhou,

Zhao

et al. 2024

J of Applied Polymer Sci

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Coaxial composite fibers with a cortex of polyacrylonitrile (PAN) and a core layer of mesophase pitch (MP) and PAN were prepared by wet spinning, then heat‐treated in air. The effects of heat treatment on the thermal reaction characteristics, pre‐oxidation degree, radial structure, and thermal stability of coaxial composite fibers were studied by differential scanning calorometry, Raman, and thermogravimetric analysis. As the heat treatment temperature increases, the coaxial composite fibers only undergo cyclization without oxidation, the peak temperature of the thermal reaction increases from 258 to 270°C, and the enthalpy increases from 19.66 to 237.82 J g−1, the heat mainly arises from the PAN component. The Dr value of the coaxial fiber skin layer increases from 0.193 to 0.255 (330°C) and then decreases to 0.236; the core layer Dr value increases from 0.353 to 0.392 (310°C) and then decreases to 0.368. The pre‐oxidation reaction leads to an increase in sp2‐hybridized carbons and an increase in pre‐oxidation degree. When the heat treatment temperature <310°C, the pre‐oxidation degree of the composite fibers increases, leading to formation of a more stable structure compared with that at lower temperatures and an increase in the carbon residue rate.

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“…With the increasing demands required of aerospace vehicles, the performance of carbon fibers also requires improvement. Owing to the extremely harsh environment in outer space, the temperature can be up to several 100°, and the shape of an aircraft will deform, and it is likely that it will be unable to complete important tasks 3–5 . Therefore, carbon fibers that exhibit small deformation under stress are required; that is, carbon fibers with high tensile modulus.…”

Section: Introductionmentioning

confidence: 99%

Effect of the polyacrylonitrile mass fraction on the structure of coaxial polyacrylonitrile/mesophase pitch composite fibers

Zhou

Zhang

Deng

et al. 2023

J of Applied Polymer Sci

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To minimize structural heterogeneity during graphitization of polyacrylonitrile (PAN)‐based carbon fibers, the present authors prepare coaxial composite fibers with PAN as the skin and a PAN/MP mixture as the core by wet spinning with coaxial spinning needles. With increasing PAN mass fraction in the skin‐layer solution, the crystallinity of the coaxial composite fibers increases from 24.3% to 31.4%, and the crystal plane spacing of the coaxial composite fibers decreases from 0.529 to 0.523 nm. The tensile strength of the coaxial composite fibers increases by 122%, attributable to the crystallinity increase from 24.3% at 10 wt% PAN to 31.4% at 15 wt% PAN. Scanning electron microscope images of the coaxial fibers demonstrate that the cortical region changes from a porous, loose structure to a less porous, denser structure. Gray value testing of the coaxial composite fibers shows that transition layers formed at the interface between the cortex and core layers, which was formed for the outward diffusion of the core‐layer MP and PAN mixed solution. With increasing PAN mass fraction, because of the high viscosity of the cortical PAN solution, diffusion of the core‐layer mixed solution to the cortical layer decreases, resulting in a 75.2% increase in the core area ratio of the coaxial composite fibers.

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Radio Frequency Heating Response of Polyacrylonitrile (PAN) Films and Nanofiber Mats

Cited by 7 publications

References 30 publications

Recent progress in microwave-assisted preparations of 2D materials and catalysis applications

Recent progress in microwave-assisted preparations of 2D materials and catalysis applications

Effect of heat treatment on the radial structure of coaxial polyacrylonitrile/mesophase pitch composite fiber

Effect of the polyacrylonitrile mass fraction on the structure of coaxial polyacrylonitrile/mesophase pitch composite fibers

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