橡胶吸波材料的研究进展

吸波材料是指能吸收并衰减投射到它表面的电磁波,并通过材料的损耗将其转变为热能或其他形式的能量耗散掉的功能性材料。通过将电磁波吸收剂填充到橡胶中制备成的橡胶吸波材料,结合了吸波剂对电磁波的损耗能力和橡胶优异的力学性能。总结了近年来国内外橡胶吸波材料的的发展现状,考察了不同的吸波剂在单一橡胶体系中的分布状态以及吸波剂在二元橡胶并用体系中的选择性分布对吸波材料吸波效果的影响。     

橡胶吸波材料的研究进展

吸波材料是指能吸收并衰减投射到它表面的电磁波,并通过材料的损耗将其转变为热能或其他形式的能量耗散掉的功能性材料。通过将电磁波吸收剂填充到橡胶中制备成的橡胶吸波材料,结合了吸波剂对电磁波的损耗能力和橡胶优异的力学性能。总结了近年来国内外橡胶吸波材料的的发展现状,考察了不同的吸波剂在单一橡胶体系中的分布状态以及吸波剂在二元橡胶并用体系中的选择性分布对吸波材料吸波效果的影响。     

频率选择性阻尼夹芯吸波复合材料

提出多层吸波预浸料层和吸波阻尼层相互嵌合的频率选择性阻尼夹芯吸波复合材料,通过规律性调节吸波预浸料层和吸波阻尼层的厚度,实现对不同频段电磁波的吸收,运用Matlab对其吸波频率选择性进行了理论分析,吸波预浸料层和吸波阻尼层的具体厚度可以根据电磁吸波频段的具体要求来设计。电磁吸波试验验证了电磁吸波频率的选择性以及理论分析方法的有效性和合理性。模态试验、自由衰减试验获得了模态参数、阻尼损耗因子随吸波预浸料厚度变化的曲线,实验数据表明:随着试件吸波预浸料层厚度的增加,电磁吸收频率发生改变,模态固有频率升高,模态阻尼比增大,阻尼损耗因子增加。     

多孔集料砂浆的吸波特性

对发泡聚苯乙烯、膨胀珍珠岩、页岩陶粒等3种多孔集料填充水泥基复合材料的电磁波吸收性能进行了研究。结果表明：多孔集料提高了复合材料与自由空间的波阻抗匹配程度,还可引起电磁波多次反射和散射,从而使电磁波迅速衰减;多孔集料填充率、集料种类、集料粒径等对电磁波吸收性能有显著影响;选用的多种集料中发泡聚苯乙烯对复合材料吸波性能的...     

GF/ACF电路屏复合材料吸波性能研究

将一定尺寸的玻璃纤维片(GF-sheet)填充至矩形活性碳纤维(Activated Carbon Fiber,ACF)电路屏空穴中,制备了GF/ACF电路屏复合材料,研究了GF-sheet尺寸对ACF电路屏复合材料电磁波反射及吸收特性的影响。结果表明,在均匀分布的ACF电路屏空穴中填充相应尺寸的GF-sheet能有效降低复合材料对电磁波的反射特性,增强吸波能力;GF水平排布的反射性能优于垂直排布;当在正方形ACF电路屏空穴中填充边长l=2 cm的GF-sheet时,最低反射值达到-29.8 d B,其吸波性能较未填充GF-sheet的复合材料,其-10 d B以下的最低反射衰减提高了60.4%,达到-21.5 d B,有效带宽有所拓宽;当在长方形ACF电路屏空穴中填充l=2 cm,w=1 cm的GF-sheet,反射衰减最低,最低反射衰减为-16.1 d B,有效带宽为12.1 GHz。     

环氧树脂/碳纤维吸波涂层电磁特性的实验研究

对环氧树脂/碳纤维吸波涂层的电磁特性进行了研究,包括对体系电磁参数及反射率的测量,纤维长径比、体积含量对电磁参数及吸波性能的影响,以及电磁参数与吸波性能的关联。结果表明,在8～18GHz频段内,随碳纤维长度的增大其介电常数实部与虚部值均增大,磁导率虚部值增大,吸收效果逐渐增强;随碳纤维体积含量的增加,其介电常数实部与虚部值均显著提高,吸收效果逐渐增强,吸收峰向低频方向移动。     

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。     

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。     

含有短切导电纤维聚氨酯泡沫塑料的吸波性能研究

通过对一种含导电短纤维的聚氨酯(PUR)泡沫塑料吸波性能的研究,探讨了纤维吸收剂的电导率、含量和泡沫塑料试样厚度对PUR泡沫塑料吸波性能的影响。结果表明,在一定范围内,纤维电导率增大可使PUR泡沫塑料对电磁波的损耗增加;纤维含量增大可增加其谐振子数目,有利于衰减电磁波;试样厚度增加可使PUR泡沫塑料吸波性能增强,在Ka波段尤为明显。     

吸波材料研究进展

简述了吸波材料的吸波物理机理、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。     

石墨-石膏基吸波复合材料的制备与性能

采用弓形反射率测试系统等现代测试手段,通过测试复合材料在2～18GHz频率范围内的吸波性能和力学性能,研究了石墨掺量、试样厚度对石膏基吸波复合材料吸波性能的影响以及石墨掺量对力学性能的影响.研究表明,石墨-石膏基材料在2～18GHz具有较好的吸波性能,厚度一定,当石墨掺量为25wt％时试样吸波性能最佳;增大厚度有利于提高试样的吸波性能,掺量20wt％,厚度为20mm的试样小于-5dB的连续带宽高达15.68GHz;复合材料的力学性能随石墨掺量的增加而逐渐减小,掺量为40wt％时,其28d的抗压和抗折强度与空白试样相比分别下降了67.9％和76％.     

短切导电纤维填充的复合材料吸波性能研究

本文研究了不同含量的短切导电纤维、吸收剂以及不同含量吸收剂/短切导电纤维混合体系对复合材料吸波性能的影响,并在此基础上确定了合理的吸收剂混合比例,研制出8～18GHz频率范围内反射率小于-10dB的结构吸波材料.     

Preparation and characterization of carbonyl iron powder/millable polyurethane elastomer microwave absorbing patch

A microwave absorbing patch (MAP) was prepared by compounding millable polyurethane elastomer (MPU) and carbonyl iron powder (CIP). Surfaces of CIP were modified using silane coupling agents (SCA). The effects of different types and amounts of SCA, the amount of vulcanizing agent and the amount of CIP on the microstructure and mechanical properties were investigated. SCA was found to improve the interface compatibility between MPU and CIP and also reinforced the mechanical properties of MAP. The KH550 was the best modifier, and the optimal dosage of KH550 was 2% of the mass of CIP based on a comparison of tensile properties. The optimal dosage of the vulcanizing agent DDPH was 3% of the mass of MPU. However, a large number of CIP could be filled into MPU. The maximum filling content of CIP increased with the increasing Mooney viscosity of MPU, and the maximum filling content of CIP was 1200% of the mass of MPU. The electromagnetic parameters and reflection loss of MPU absorbers and MPU filled with CIP absorbers were measured in the 1–18 GHz frequency range. The absorbers of MPU filled with CIP had excellent microwave absorbing properties compared with the absorbers of MPU. POLYM. COMPOS., 35:1318–1324, 2014. © 2013 Society of Plastics Engineers     

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.     

EP/SCF吸波涂层的介电性能和吸波效果研究

选择电导率不同的短碳纤维(SCF)为吸收剂制备了一系列环氧树脂(EP)/SCF吸波涂层,在一定的频率范围内测试EP/SCF涂层的介电常数和反射率,研究了SCF的电导率对EP/SCF涂层介电性能和吸波性能的影响。结果表明,在一定条件下,SCF的电导率越大,在8~18 GHz频段内EP/SCF涂层的介电常数实部和虚部也越大;EP/SCF涂层在8~18 GHz频段的吸波性能也随着SCF电导率的增大而增强;EP/SCF涂层的吸波性能在8~18 GHz频段内存在最大吸收点,越靠近最大吸收点,SCF的电导率对涂层吸波性能的影响越明显。     

Dielectric and microwave absorption properties of CB doped SiO2f/PI double-layer composites

Carbon black (CB) with contents of 5.5?wt% and 15?wt% filled quartz glass fiber reinforced polyimide (SiO_2f/PI) composite were designed and prepared. A double-layer absorbing material was designed using the two composites materials as a matching layer and an absorption layer, respectively. The microwave absorption property of single-layer and double-layer composites is calculated according to transmission line theory. The results show that the microwave absorbing property of double-layer composite is better than that of single-layer at the same thickness. When the 5.5?wt%CB doped SiO_2f/PI composite is used as the matching layer with a thickness of 0.7?mm and 15?wt%CB doped SiO_2f/PI composite is used as the absorption layer with a thickness of 0.9?mm, the RL (reflection loss) of the composite reaches a minimum value of ?46.18?dB at 16.07?GHz. Meanwhile, the bandwidth of RL?≤??5?dB is 5.87?GHz and the bandwidth of RL?≤??10?dB is 3.95?GHz.     

CaCO3填充型聚丁二烯聚氨酯弹性体的研究

以端羟基聚丁二烯、液化改性二异氰酸(MDI)为原料，用或不用丁二醇作扩链剂，加入CaCO3，用机械搅拌或超声分散法合成填充型聚丁二烯聚氮酯(HTPB-PU)弹性体。并对填充型HTPB-PU弹性体的力学性能、热性能以及水解性能进行了研究，同时用扫描电镜研究了弹性体的应力断裂的断口形态。结果发现，随填料加入量的增多，弹性体的强度增大；填料加入量相同时，纳米CaCO3填充型HTPB-PU弹性体的力学性能和抗水解性能均优于普通CaCO3填充型；采用超声波分散相同时，HTPB-PU弹性体中的CaCO3分散得比采用机械搅拌分散时均匀得多；弹性体中存在明显的两相分离。     

聚天冬氨酸/聚丙烯酸互穿网络吸水性树脂的制备

以交联聚天冬氨酸(PAsp)、丙烯酸(AAc)为原料,以过硫酸钾为引发剂,以N,N′-亚甲基双丙烯酰胺为交联剂,采用分步法制备了聚天冬氨酸/聚丙烯酸(PAAc)互穿网络吸水性树脂(IPNAP),并对其结构进行了表征,探讨了AAc与PAsp质量比、引发剂用量(以单体质量计,下同)、交联剂用量(以单体质量计,下同)、AAc中和度对IPNAP吸液性能的影响。结果表明,当AAc与PAsp质量比为1.0∶1、引发剂用量为0.50%、交联剂用量为0.40%、AAc中和度为75%时,IPNAP的吸液性能最好,在蒸馏水和生理盐水中的吸液倍率分别达到826g·g-1和120g·g-1。     

Enhanced microwave absorbing properties of lightweight films based on polyaniline/aliphatic polyurethane composites in X band

Polymer blends based on nanostructured polyaniline (PANI) doped with hydrochloric acid (HCl) and para‐toluene sulfonic acid (PTSA) introduced into aliphatic polyurethane matrix (PU) are synthesized to produce flexible thin composite films for microwave absorbers. The effects of dopant type, PANI content and film thickness on morphologies, dielectric and microwave absorption properties in the X‐band are studied. It reveals that real and imaginary parts of the complex permittivity are proportional to filler concentrations and type of doped PANI. The PANI‐PTSA/PU films show higher permittivity and better microwave absorbing properties than PANI‐HCl/PU for the same weight fraction of PANI. The minimum reflection loss RL_(dB) values for the PANI‐PTSA/PU are ?37 dB at (20% PANI and 11.6 GHz) and ?30 dB at (15% PANI and 11.3 GHz) for thicknesses of 1.2 and 1.6 mm, respectively. These high values of reflection losses make the obtained lightweight and flexible composites promising radar absorbing materials (RAM). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40961.     

微螺旋炭纤维的微波电磁参数及其环氧复合材料的吸波性能研究

采用化学气相沉积法制备了微螺旋炭纤维(CMCs),研究了其在频率为8.2￣12.4GHz范围内的微波介电特性;以环氧树脂为胶粘剂制备了CMCs/环氧复合吸波涂层,并对其吸波性能进行了研究。结果表明,随着CMCs含量的增加,复介电参数实部ε′、虚部ε″和介电损耗tanδ均有所增加,当CMCs含量为1%￣5%时,ε″和tanδ增幅很小;当CMCs含量为10%时,两者增幅显著增大。ε′表现出高频减小的趋势,同时tanδ表现出高频增大的趋势,这些均有利于实现高频吸波。磁损耗tanξ较小且CMCs含量对其影响不明显。CMCs/环氧复合吸波涂层的反射率随着CMCs含量的增加而明显减小,表现出高频衰减略有增加的趋势,同时出现多吸收峰,这有利于实现宽频吸波。