Preparation and Evaluation of a Polyimide-Coated Ultrafine Gilt Molybdenum Wire and Its Knitted Mesh Used for Electromagnetic Reflectors

Shao, Huiqi; Chen, Nanliang; Li, Shuang; Lin, Fangbing; Jiang, Jinhua; Ma, Xiaofei

doi:10.3390/polym9120734

Cited by 9 publications

(4 citation statements)

References 31 publications

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“…Polyimide (PI) filaments as reinforcements for advanced composites have attracted considerable research attention for their favorable thermal stability, outstanding mechanical properties, excellent chemical and radiation resistance, and special dielectric properties [1,2,3,4,5]. For composites, good interfacial adhesion between fiber and matrix facilitates the load transfer efficiency and improves the strength and toughness of the composite materials [6,7,8,9].…”

Section: Introductionmentioning

confidence: 99%

High-Performance Polyimide Filaments and Composites Improved by O2 Plasma Treatment

Lin

Tang³

et al. 2018

Polymers

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Abstract:Interface issues urgently need to be addressed in high-performance fiber reinforced composites. In this study, different periods of O 2 plasma treatment are proposed to modify twist-free polyimide (PI) filaments to improve hydrophilicity and mechanical and interfacial properties. Feeding O 2 produces chemically active particles to modify the filament surface via chemical reactions and physical etching. According to the X-ray photoelectron spectroscopy (XPS) results, the PI filaments exhibit an 87.16% increase in O/C atomic ratio and a 135.71% increase in the C-O functional group after 180 s O 2 plasma treatment. The atomic force microscope (AFM) results show that the root mean square roughness (Rq) of the treated PI filaments increases by 105.34%, from 38.41 to 78.87 nm. Owing to the increased surface oxygenic functional groups and roughness after O 2 plasma treatment, the contact angle between treated PI filaments and water reduces drastically from the pristine state of 105.08 • to 56.15 • . The O 2 plasma treated PI filaments also demonstrate better mechanical properties than the pristine PI filaments. Moreover, after O 2 plasma treatment, the adhesion between PI filaments and poly(amic acid) (PAA) is enhanced, and the tensile strength of the polyimide/poly(amic acid) (PI/PAA) self-reinforced composites increases from 136 to 234 MPa, even causing the failure mode of the composite changes from adhesive failure to partly cohesive failure.

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Section: Introductionmentioning

confidence: 99%

High-Performance Polyimide Filaments and Composites Improved by O2 Plasma Treatment

Lin

Tang³

et al. 2018

Polymers

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“…Excellent performance of polyimides like highly mechanical and thermally stable, electrical, wide chemical resistance, and relatively low dielectric constants, and so forth makes themselves attractive candidates in microelectronic and aerospace engineering . Over the past years, numerous diamines or dianhydrides are designed aiming to obtain polyimides with ultralow dielectric constant, high glass transition temperature, good biocompatibility, low coefficient of linear expansion, ultrahigh tensile strength, optoelectronic and gas separation properties, and so forth, Nevertheless, most of these polyimides based on aromatic building blocks can easily lead to defects like insolubility and low transmittance and hence impede their molding processing and application in optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Transparent and soluble polyimide films containing 4,4′‐isopropylidenedicyclohexanol (Cis‐HBPA) units: Preparation, characterization, thermal, mechanical, and dielectric properties

Liu

Wang

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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To develop colorless and soluble polyimide films, cis‐hydrogenated bisphenol A (cis‐HBPA) was successfully separated from HBPA isomers, and two novel monomers containing cis‐HBPA unit, 4,4′‐(4,4′‐isopropenylbicyclohexyloxy) diphthalic anhydride (HBPADA) and 4,4′‐(4,4′‐isopropenylbicyclohexyloxy) dianiline (f) were designed and synthesized. PI–(1 – 5) were achieved from HBPADA and five kinds of aromatic diamines and PI – 6 from HBPADA and semiaromatic diamine f via a two‐step thermal imidization. All the polyimides could afford flexible, tough, and transparent films with transparency as high as 86% at 450 nm. Surprisingly, the polyimides containing cis‐HBPA unit exhibited excellent solubility not only in polar solvents such as N, N‐dimethylacetamide, but also in low boiling solvents such as chloroform and dichloromethane. Additionally, analogues aromatic PI – 7 derived from 4,4′‐(hexafluoroisopropylidene)‐diphthalic anhydride (6FDA) and 2,2‐bis(4‐aminophenyl)hexafluoropropane (e) was obtained for comparison with PI–(1 – 6) on aspects of thermal, mechanical, soluble, optical, electrical, and morphological properties. The structure‐property relationships of PI–(1 – 7) were investigated in detail. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2115–2128

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“…Li et al 34 reported flexible warpknitted metal meshes in terms of the design requirements, materials, and knitting process. Shao et al 35 reported knitted polyimide-coated gilt molybdenum mesh fabrics for antenna applications, which show strong reflectivity for EM microwaves in the S-band. As a consequence, employing warp-knitting technology to link ultra-fine metal wires with micron diameters into flexible mesh-shaped materials has considerable potential for the preparation of excellent EMI shielding materials.…”

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Investigation of flexible warp-knitted metal meshes for electromagnetic interference shielding

Zheng

Shao

et al. 2022

Textile Research Journal

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This paper develops four novel warp-knitted structures with two bars of the one-in one-out threading mode and describes the investigation of electromagnetic interference (EMI) shielding metal meshes composed of contiguous ultra-fine metal wires fabricated using warp-knitting technology. The mechanical properties, electrical conductivity, and microwave shielding effectiveness (SE) of the flexible meshes are assessed in terms of the mesh structure, mesh material, and warp run-in parameter. The results reveal that the metal mesh has a flexible and stable mechanical property, good electrical conductivity, and optimal EMI performance when the mesh structure is open lap atlas. The gold-coated molybdenum mesh exhibits the lowest electrical resistivity (5.18 × 10−5 ohm/sq) and optimal average EMI SE (–21.04 dB), making it a candidate for EMI shields for intelligent wearable electronic devices. The warp run-in can adjust the EMI SE, and the optimum average EMI SE (–25.52 dB) can be obtained when the warp run-in is set at the 2580 rack. Moreover, the warp-knitted metal meshes show desirable EMI shielding efficiency persisting at >70% even at large strain deformations and under cyclic bending and twisting deformations. Conductive warp-knitted meshes with a millimeter period and micron-scale wire diameter exhibit an adequately large scale, satisfactory mechanical stability, excellent flexibility, permanent conductivity, and strong microwave reflection, simultaneously. Moreover, the EMI SE of warp-knitted metal mesh reaches the protection level (–20 dB) prescribed by standard electronic devices. Therefore, the warp-knitted metal meshes show great potential in flexible and wearable EMI shielding devices.

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Preparation and Evaluation of a Polyimide-Coated Ultrafine Gilt Molybdenum Wire and Its Knitted Mesh Used for Electromagnetic Reflectors

Cited by 9 publications

References 31 publications

High-Performance Polyimide Filaments and Composites Improved by O2 Plasma Treatment

High-Performance Polyimide Filaments and Composites Improved by O2 Plasma Treatment

Transparent and soluble polyimide films containing 4,4′‐isopropylidenedicyclohexanol (Cis‐HBPA) units: Preparation, characterization, thermal, mechanical, and dielectric properties

Investigation of flexible warp-knitted metal meshes for electromagnetic interference shielding

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