静电纺丝技术制备铁氧体吸波材料的研究现状与进展

纳米吸波材料因其独特的量子尺寸效应和良好的吸波能力,逐渐成为近年来吸波材料的研究热点。静电纺丝技术是一种制备纳米纤维最简单有效的方法,科研人员已经将其应用于铁氧体吸波材料的制备中。该文介绍了静电纺丝技术制备铁氧体吸波材料的研究进展,着重介绍了几种改善铁氧体吸波材料性能的方法,并对静电纺丝制备铁氧体吸波材料进行了总结与展望。     

碳纤维增强复合材料微波吸收性能研究进展

传统的铁基复合材料和陶瓷基复合材料存在密度大、吸收性能差、吸收频带窄等缺点，在电磁波吸收领域应用受限。近年来，碳基复合材料具有密度低、电导率高等优点，成为备受关注的吸波材料。碳纤维增强复合材料（CFRP）作为一种轻质、高强度、高刚度和耐高温的材料，在吸波材料领域具有独特的优势。文章介绍了吸波材料的作用机理和电磁波损耗机理，并综述了近年来碳纤维增强复合材料（CFRP）吸波改性的研究进展。其中吸波改性主要分为两大类，一类是在材料基体中引入特殊的物质和结构，包括磁性金属改性、纳米改性、表面结构改性；另一类则是对材料表面进行涂层处理，包括复合涂层和梯度涂层。文章对CFRP吸波复合材料的发展趋势进行展望。     

纤维吸波材料的研究进展

电磁波防护对通信电子、国防军事、健康防护等领域具有重要意义,研究开发高效电磁波吸波材料刻不容缓。纤维吸波材料因其比表面积大、形状各向异性、电磁性能可调性好的特点,引起了国内外学者的广泛关注和研究。简述了吸波材料的电磁波吸收损耗原理,重点阐述了纤维吸波材料的制备方法,总结了不同类型纳米纤维吸波材料的特点及其吸波性能,并对性能好、实用性强的纤维吸波材料今后研究方向进行了展望。     

静电纺丝技术发展简史及应用

静电纺丝现已成为一种重要的纳米纤维成形技术,制备的纳米纤维也得到了广泛应用。介绍了静电纺丝技术的基本原理及发展历程,以及采用静电纺丝技术制备的纳米纤维品种、纳米纤维的应用领域等。采用静电纺丝技术可以制备各种不同结构和形态的纳米纤维,如有机纳米纤维、有机/无机杂化复合纳米纤维、无机纳米纤维、碳纳米纤维等;通过静电纺丝制备的纳米纤维因具有特殊结构和优异性能,在过滤材料、能源材料、生物医用材料、传感器和光催化等领域得到广泛应用。今后在完善实验室技术的基础上,应加强静电纺丝技术的产业化研究。     

静电纺丝制备聚丙烯腈纳米碳纤维

利用静电纺丝制备连续的聚丙烯腈纳米碳纤维;介绍了静电纺丝的原理、影响静电纺丝的主要因素以及制备纳米碳纤维、纳米活性炭纤维、纳米碳纤维复合材料的方法和原理;分析了静电纺丝产率低,难以得到单向平铺的纤维等问题,影响静电纺丝的参数主要有溶液特性、纺丝工艺参数、纺丝环境参数。由静电纺丝得到纳米聚丙烯腈纤维,然后再经预氧化和碳化制备纳米碳纤维,或把纳米纤维预氧化,经活化、碳化制备纳米活性炭纤维。并指出纳米碳纤维具有巨大的潜在应用空间。     

静电纺丝制备氟化物纳米纤维研究进展

静电纺丝法是目前能够直接连续制备纳米纤维唯一有效的方法,通过静电纺丝的法制得的纳米纤维具有比表面积大、孔隙率高、长径比大及力学性能好等优点。简述了静电纺丝基本工作原理及重要的工艺影响参数,阐述了静电纺丝制备含氟有机物、金属氟化物和其他各类纳米纤维的研究现状,以及这些纳米纤维材料在诸多领域的实际应用,也指出了静电纺丝技术自身存在的一些问题。     

静电纺丝制备纳米纤维的进展及应用

简述了静电纺丝的制备原理和影响静电纺丝纤维成形的主要工艺因素;介绍了静电纺丝法制备高分子聚合物、生物大分子、无机物纳米纤维的最新进展,以及这些纳米纤维在过滤、传感器、超疏水性材料、生物医用功能材料、纳米模板等领域的应用;指出静电纺丝制备纳米连续长丝技术亟待发展。     

静电纺纳米纤维市场前景看好

20世纪90年代后期，科学家们对于纳米纤维制备及应用的研究达到高潮，开发了一系列制备聚合物纳米纤维的方法，如纺丝、模板合成法、相分离法、自组装法以及静电纺丝法等。与上述方法相比，静电纺制备聚合物纳米纤维具有设备简单、操作容易以及高效等特点，是制备聚合物连续纳米纤维最有效的方法。静电纺纳米纤维性能优异、应用广泛，在电子器件、生物医学领域、滤材、防护服用材料纤维增强复合材料及传感器感知膜的应用前景十分看好，产业化市场发展前景广阔。     

吸波材料研究进展

由于电磁波在军事、工业及民用产品中的应用迅速增加,电磁干扰已经成为一种新的社会污染,电磁辐射也对人体健康和各种电子设备造成巨大危害。因此具有吸收电磁波功能的材料已成为近年研究和应用的热点。随着隐身与反隐身技术的发展、电真空器件对大功率的需求以及电子通讯的广泛普及,电磁波吸收材料当前功能材料领域的研究热点之一。本文简述了吸波材料吸波物理机理,吸波特性,吸波材料分类以及吸波材料的应用领域。并最终结合实际指出多晶金属纤维、SiC基陶瓷和C/C复合材料是目前性能最佳、应用前景最好的电磁波吸收材料。     

静电纺丝技术制备无机功能复合纳米纤维的研究进展

目前,静电纺丝技术是唯一能够直接、连续制备聚合物纳米纤维的方法。随着功能材料的发展,单一组分的聚合物纳米纤维在功能上已经不能满足现有的应用领域。由于一些纳米无机功能粉体在光学、电学、催化等方面具有优越的性能,因此逐渐发展成在聚合物中加入纳米级无机功能粉体,采用静电纺丝技术可以得到无机复合纳米纤维,不仅满足了原有的应用性能,而且在一些特殊的领域能够表现出更加优越的性能。为此本文概述了静电纺丝技术在无机复合纳米纤维制备方面的最新研究进展,分析了静电纺丝工艺在制备无机复合纳米纤维方面存在的主要问题。最后指出了静电纺丝技术制备硅藻土复合纳米纤维所面临的问题,以及应该采取的对策。     

Recent advances in carbon nanotubes-based microwave absorbing composites

With the blossom of information industry, electromagnetic wave technology shows increasingly potential in many fields. Nevertheless, the trouble caused by electromagnetic waves has also drawn extensive attention. For instance, electromagnetic pollution can threaten information safety in vital fields and the normal function of delicate electronic devices. Consequently, electromagnetic pollution and interference become an urgent issue that needs to be addressed. Carbon nanotubes (CNTs) have become a potential candidate to deal with these problems due to many advantages, such as high dielectric loss, remarkable thermodynamic stability, and low density. With the appearance of climbing demands, however, the carbon nanotubes combining various composites have shown greater prospects than the single CNTs in microwave absorbing materials. In this short review, recent advances in CNTs-based microwave absorbing materials were comprehensively discussed. Typically, we introduced the electromagnetic wave absorption mechanism of CNTs-based microwave absorbing materials and generalized the development of CNTs-based microwave absorbers, including CNTs-based magnetic metal composites, CNTs-based ferrite composites, and CNTs-based polymer composites. Ultimately, the growing trend and bottleneck of CNTs-based composites for microwave absorption were analyzed to provide some available ideas to more scientific workers.     

Carbon–ceramic nanofiber embedded with LDHs-derived composites for enhanced electromagnetic wave absorption

Hydrotalcite-like layered double hydroxides (LDHs) exhibit distinct microstructures and atomic compositions, and thus, they are expected to be superior microwave absorbing materials. However, preparation of excellent absorbers from LDHs is still a challenging task. Herein, NiCo-LDHs@SiC/C heterostructure composites were designed and then heat-treated to obtain NiCo@SiC/C nanofibers. Finally, with a synergistic effect of dielectric and magnetic losses, the minimum reflection loss value of the sample could reach −56.3 dB with a thickness of 2.7 mm, and the maximum effective bandwidth absorption reached 6.8 GHz at 2.3 mm. Moreover, the simulated radar cross-section indicates that the NiCo@SiC/C nanofibers well suppress the electromagnetic scattering from metal trench structure. This result further indicates the outstanding microwave absorption properties of the nanofibers. This study contributes to the development of LDH materials in the field of wave-absorbing materials, and is an important guideline for exploring efficient microwave absorbers with fibrous structure.     

Electrospun nanofiber: Emerging reinforcing filler in polymer matrix composite materials

The rapidly developing technique of electrospinning has gained surging research interest since the 1990s due to its capability of yielding continuous fibers with diameters down to the nanometer scale. Despite enormous efforts devoted to explore applications of electrospun nanofibers, such as separation, catalysis, nanoelectronics, sensors, energy conversion/storage, and biomedical utilization, there are limited attempts to employ these nanofibers for reinforcement in polymer composites. Electrospun nanofibers, however, possess comprehensive advantages not typically shared by other nanoscale composite fillers/reinforcing agents, such as continuity, diverse material choice, controlled diameter/structure, possible alignment/assembly, mass production capability and so forth. Therefore electrospun nanofibers have great potential as promising reinforcement fillers for next-generation polymer composites. This is a comprehensive and state-of-the-art review of the latest advances made in development of electrospun nanofiber reinforced polymer composite materials with intention to stimulate interests in both academia and industry.     

Electromagnetic wave absorbing properties of In–Sn/rGO composites supported by impurity defect

With the fast development of E-communication technology, effective electromagnetic wave absorbing materials are highly needed to address the growing electromagnetic pollution. Herein, Indium doped tin microsphere/reduced graphene oxide (In–Sn/rGO) composites with rich impurity defects were synthesized via the sol-gel and hydrothermal method. The excellent microwave absorption of In–Sn/rGO composites can be attributed to the modifications of electronics status and Fermi energy level after In doping. This can significantly increase the carrier mobility between In–Sn microspheres and rGO sheets to strike a superior interfacial polarization loss. As a result, the maximum absorptivity can reach ?51.16 dB at 8.73 GHz (thickness: 3.5 mm) with a lower filler loading of 10 wt%. Meanwhile, the synthesized In–Sn/rGO composites also exhibit an ultra-wide absorbing frequency range of 13.84 GHz (within the X band, Ku band, and most of the C band). This research provides a new idea for the synthesis of effective microwave absorbing material by introducing impurity defects.     

Electromagnetic and microwave absorption properties of FeSiAl and flaky graphite filled Al2O3 composites with different FeSiAl particle size

The increasing electromagnetic interference problems have drawn much attention to microwave absorbing materials. To satisfy the needs of practical application, FeSiAl and flaky graphite filled Al₂O₃ composites were sintered by hot-pressing for microwave absorption application. The effect of FeSiAl particle size on the electromagnetic and microwave absorption properties was investigated in the X-band (8.2–12.4 GHz). The results show that the dielectric properties enhance significantly with increasing FeSiAl particle size, which is attributed to the increased interfacial polarization and conductance loss. As a result of the favorable impedance matching and appropriate electromagnetic attenuation, the reflection loss (RL) of the composites filled with 25–48 μm flaky FeSiAl achieves -15.2 dB at 10.6 GHz and the effective absorption bandwidth (RL < -10 dB) is 1.2 GHz in 10.0–11.2 GHz with a matching thickness of 1.0 mm. It indicates that FeSiAl and flaky graphite filled Al₂O₃ composites are potential candidates for thin-thickness microwave absorbing materials, and the microwave absorption properties can be enhanced by adjusting absorbent particle size.     

A review on electrospinning nanofibers in the field of microwave absorption

As important functional materials for absorbing and attenuating incident electromagnetic waves, microwave absorption (MA) materials have found a wide range of applications in civil and military fields. In addition to the study of the compositions, the structural design of the MA materials is also a research hotspot in the field. Among the various structures, the one-dimensional (1D) structure has drawn wide attention because of the unique shape anisotropy and spatial confinement effect. Electrospinning technology has become one of the main ways to prepare continuous 1D micro-nano fibers due to the advantages of many types of spinnable materials, low spinning cost, and high controllability of process parameters. This review involves an introduction and a classification of the research progresses achieved in electrospinning technology concerning MA nanofibers from the perspective of compositions, as well as the list of their minimum reflection loss (RL_min) and effective absorption bandwidth (EAB).     

碳纳米管在聚合物基吸波复合材料中的应用

碳纳米管作为一种新型电磁吸波剂,因其独特的物理和化学性能引起了人们极大的关注。本文简述了碳纳米管的吸波机理及吸波性能的表征,重点介绍了碳纳米管在聚合物吸波复合材料中的应用,如碳纳米管/树脂基复合材料、碳纳米管/导电高聚物复合材料、碳纳米管/橡胶基复合材料,最后展望了吸波材料的发展方向。     

Polymer-based composites by electrospinning: Preparation & functionalization with nanocarbons

Electrospinning is a straightforward yet versatile technique for the preparation of polymeric nanofibers with diameters in the range of nanometers to micrometers, and has been rapidly developed in the last two decades. Nanocarbon materials, usually referring to carbon nanotubes, graphene, and fullerenes with their derivatives including quantum dots, nanofibers, and nanoribbons, have received increasing attention due to their unique structural characteristics and outstanding physico-chemical properties. Incorporation of nanocarbons in electrospun polymeric fibers has been used to increase the functionality of fibers, for example, to improve the mechanical, electrical, and thermal properties, as well as confer biofunctionality as scaffolds in tissue engineering and sensors, when the advantageous properties given by the encapsulated materials are transferred to the fibers. In this review, we provide an overview of polymer-based composites reinforced with nanocarbons via the electrospinning technique. After a brief introduction of various types of nanocarbons, we summarize the latest progress of the design and fabrication of electrospun polymeric nanofibers with nanocarbon fillers. With regard to the preparation of composites, we focus on functionalization strategies of nanocarbons and the production of random & aligned polymeric nanocomposites. Then, the physical properties such as mechanical, electrical, and thermal properties are also reviewed for electrospun nanocomposite nanofibers reinforced with nanocarbons, especially carbon nanotubes. Benefiting from the exceptional properties including superior electric conductivity, high porosities, unique mat structure, etc. the polymeric composite nanofibers have demonstrated numerous advantages and promising properties in the fields of tissue engineering and sensors. In the application section, we will give state-of-the-art examples to demonstrate the advantages of electrospun polymer-based nanocomposites. Finally, the conclusion and challenge of the polymer-based nanocomposites are also presented. We believe the efforts made in this review would promote the understanding of the methods of preparation and unique physical and chemical properties of nanocarbon reinforced polymer-based nanocomposites.     

Recent progress in synthesis,growth mechanisms,and electromagnetic wave absorption properties of silicon carbide nanowires

With the research and development of nanomaterials, one-dimensional (1D) nanowire structures have received a lot of attention due to their unique physical and chemical properties. Among them, silicon carbide nanowires (SiC NWs) have low density, excellent oxidation resistance, dielectric properties, and electromagnetic (EM) wave absorption properties, which can well meet the development needs of civilian equipment and military weaponry. SiC NWs have outstanding research and application potential in the field of EM wave absorption. However, comprehensive summaries of SiC NWs have not been available so far. Based on this, this paper reviews the research progress of SiC NWs microwave absorbing materials, various micro-morphologies of SiC NWs are introduced in detail, as well as diverse preparation strategies and multiple growth mechanisms are also stated. Ultimately, recent advances in research progress of SiC NWs and their composites in EM wave absorption are elaborated, along with the future research directions of SiC NWs in the field of EM wave absorption.     

纤维增强树脂基吸波复合材料的研究进展

简述了吸波材料的电磁屏蔽机制、吸波剂的分类和损耗机制以及微波波段的划分与应用,并从材料的选择、结构的设计以及获得的吸波效果等方面对目前纤维增强树脂基吸波复合材料的研究进行了对比总结,重点阐述了单层结构、多层结构、多层夹心结构以及频率选择表面的主要特点和研究现状。最后提出了纤维增强树脂基吸波复合材料目前存在的问题,并对今后的发展进行了展望。