热处理N990炭黑及其PTC复合材料的电性能

将N990炭黑进行高温热处理,把热处理后的炭黑与高密度聚乙烯熔融混合制成复合材料。采用BET、XRD和XPS方法研究热处理炭黑的结构,电阻–压力曲线评价其导电能力,电阻率–温度曲线研究其复合材料的PTC特性。结果表明,与未处理炭黑相比,高温热处理N990炭黑的晶相结构和颗粒尺寸没有明显变化,但热处理使炭黑的比表面积显著增大,表面氧元素明显减少,导电能力增加1倍以上。热处理炭黑复合材料能达到9个数量级以上的高PTC强度,同时室温电阻率下降了40%~90%。     

炭黑—聚乙烯—季戊四醇系复合材料性能研究

炭黑—聚乙烯复合材料具有正温度系数(PTC)效应,季戊四醇在185℃能发生相变.本文详细讨论不同的掺入季戊四醇含量对炭黑—聚乙烯复合材料的PTC效应、机械性能和耐击穿特性的影响。     

聚丙烯/炭黑电热材料的SEM研究

本文研究聚丙烯 炭黑复合材料的电热性能 ,用ＳＥＭ探讨在复合材料中炭黑的形态结构、性能和填充率对复合材料导电性能的影响以及不同炭黑种类填充聚合物的渗流临界值变化。实验结果表明 ,ＰＰ ＣＢ复合材料具有明显的渗流效应、正温度系数效应。1　炭黑的形态结构对复合材料导电性的影响对于炭黑填充型复合材料来说 ,加入炭黑的目的就是提高复合材料的导电性能 ,因而炭黑的结构和性质对导电性的贡献是制备这种功能材料最重要的问题[1] 。各种研究已经表明 ,炭黑要提高复合材料的导电性 ,必须在聚合物的基体中形成一种由炭黑粒子 (或聚集体…     

Ni/石墨/BaTiO3复合材料低阻化研究

采用在BaTiO3陶瓷中加入Ni粉和石墨粉,将金属Ni和石墨的良好导电性能与BaTiO3基材料优良的PTC效应相结合,旨在研究降低BaTiO3基陶瓷室温电阻率的有效途径。通过大量反复的比对实验和测试分析,制备出了具有较低室温电阻率和一定升阻比性能的正温度系数(PTC)复合材料。     

两种炭黑导电橡胶复合材料的电磁屏蔽性能

采用炭黑分别填充丁苯和丁腈橡胶,研究两种不同橡胶基体对炭黑的分散性能及复合材料导电性能、电磁屏蔽性能的影响。对比发现,丁苯橡胶基体中炭黑分散性能随炭黑含量增多而变差,而在丁腈橡胶中炭黑的分散性能呈相反趋势,随炭黑含量增多而变好。丁腈导电橡胶的导电性能以及电磁屏蔽性能要好于相同炭黑含量的丁苯导电橡胶。     

聚合物基复合材料的PTC效应机理初探

本文就复合材料的ＰＴＣ效应及影响因素进行了系统试验，并着重对聚合物基复合材料ＰＴＣ效应的渗滤－隧道机制及导电粒子链的作用进行了讨论，为优化复合ＰＴＣ材料物理性能和材料设计提供了依据。     

防静电工作表面：发展和历史（五）

提供静电放电能力的另一个材料途径是在塑料材料中混入导电填充物。早在二战时期,德国潜艇使用导电炭填充橡胶覆盖其通气管来躲避雷达探测。导电炭黑改变了橡胶的特性,可以有效地对付当时最先进的500MHz频率探测。导电填充物的使用也应用到静电放电应用中。控制静电的进一步努力在20世纪50年代后期和60年代初被报道,     

导电纤维高分子复合材料研究现状与发展趋势

介绍了国内外专家在以不锈钢纤维、铜纤维、碳纤维为填充物的导电高分子复合材料方面的研究成果,比较了这几种复合材料的性能。阐述了限制导电高分子复合材料进一步发展的因素及改进措施。     

Ni/BaTiO3陶瓷复合材料的制备及其PTC效应

为获得低室温电阻率的PTC材料,以草酸为沉淀剂,采用液相包裹法制备了NiC2O4·2H2O/BaTiO3前躯体,并由其热分解制得Ni/BaTiO3基陶瓷复合材料。对该复合材料的研究表明,在还原气氛下烧成的Ni/BaTiO3基陶瓷复合材料具有很弱的PTC效应,但其PTC效应可通过适当的热处理工艺(600℃,空气气氛)得到有效恢复。其升阻比与室温电阻率为:(ρmax/ρmin=60)和(ρ=6.1?·cm)。     

石墨、炭黑及白炭黑在橡胶中的微观结构分析

本文用ＳＥＭ技术对石墨，炭黑及白灰黑三种导电粒子导电硅橡胶中的结构分布形态进行了分析，结果发现，石墨在橡胶基体中的均匀分布，且不聚焦，炭黑和白炭黑在橡胶基体中都有聚焦成环球的现象，当炭黑和白炭黑共存时，其聚焦程度增大，由此可见，白炭黑对炭黑的聚集有影响，此外，有关导电粒子对导电硅聚橡胶导电机制的影响也进行了分析。     

Innovative ESD thermoplastic composites structured through meltflow processing

The amount of carbon black required to impart electrical conductivity to an insulating polymer can be dramatically reduced by its selective localization in a multi-component system which includes the insulating polymer The present report describes property-structure relationships of polypropylene/nylon/glass fiber (PP/PA/GF) composites with consistent resistivity levels within the 10⁶-10⁹ ohms/sq range achieved at very low carbon black loadings (less than 2%). The quaternary composites studied structure spontaneously during the hot compounding/processing steps and have unique triple-percolation structures. The results were compared with typical carbon black filled materials, which usually contain 15 to 20 wt% carbon black and are too conductive to meet the 10⁶-10⁹ ohms/sq range     

氯化丁基橡胶基压电阻尼复合材料的研究

根据新的压电-导电原理和焦耳定律,将压电陶瓷粉体复合到传统的氯化丁基橡胶阻尼材料中,制作出了性能更好的新型阻尼材料。实验结果表明,复合材料中的压电陶瓷能将机械能转化为电能,并通过微电路耗散出去。因此,通过压电效应-焦耳定律、氯化丁基橡胶的粘弹性阻尼及陶瓷粉体、乙炔碳黑粒子和橡胶分子之间的粒间摩擦、界面摩擦,复合材料可有效地阻尼外界的振动能。     

A conductive plastic for simulating biological tissue at microwavefrequencies

A conductive plastic composite that exhibits complex dielectric properties similar to biological tissues over the electromagnetic spectrum of 300-900 MHz has been synthesized from compressed carbon black mixed with a castable thermoplastic (polyethyl methacrylate). This paper presents the techniques used to control the electrical properties of the conductive plastic and describes the challenges encountered in fabricating a material containing a high proportion of carbon black. While developed to serve as a housing material for a microwave antenna array for imaging biological bodies, the composite should be useful in any setting requiring a stable, solid, high loss material that simulates biological tissues over the microwave spectrum     

半导体ZnTe/GaAs界面层错的高分辨显微分析

本项研究对经热壁外延（ＨＷＥ）生长在ＧａＡｓ基底上的ＺｎＴｅ进行分高分辨显微结构的观察，在ＺｎＴｅ／ＧａＡｓ界面上不仅存在着混合型全位错的扩展，而且首次发现类似螺旋位错分解的层错，并将其归结为原子在不全位错之后的堆积。     

碳黑用量对硅橡胶压阻材料性能的影响

以高导电纳米碳黑为导电填料,甲基乙烯基硅橡胶为基材,制备出了硅橡胶压阻材料,并对其电性能和力学性能进行了表征。研究了碳黑用量对硅橡胶压阻材料电性能、压缩应力松弛性能以及电阻蠕变性能的影响。结果表明,碳黑用量对硅橡胶压阻材料的性能影响很大。当碳黑用量为质量分数14%~16%时,所制得的硅橡胶压阻材料性能优良,在反复加载20次的过程中,其压阻曲线的重复性很好,这为其下一步的器件化提供了可能。     

Limit current surges with +TC resistors

The characteristics and design of positive temperature coefficient (PTC) resistors, which are used in current-limiting circuits that do not isolate completely the protected circuit from its power source, are described. The way in which the PTC resistor, a conductive polymer blend of specially formulated plastics and various conductive materials, works is outlined. As an example of the specification process for a PTC circuit protector, the use of a conductive polymer PTC resistor to protect an outlet circuit in a personal computer used for connecting a keyboard is considered     

Iron Oxide Nanoparticle and Graphene Nanoribbon Composite as an Anode Material for High‐Performance Li‐Ion Batteries

A composite material made of graphene nanoribbons and iron oxide nanoparticles provides a remarkable route to lithium‐ion battery anode with high specific capacity and cycle stability. At a rate of 100 mA/g, the material exhibits a high discharge capacity of ~910 mAh/g after 134 cycles, which is >90% of the theoretical li‐ion storage capacity of iron oxide. Carbon black, carbon nanotubes, and graphene flakes have been employed by researchers to achieve conductivity and stability in lithium‐ion electrode materials. Herein, the use of graphene nanoribbons as a conductive platform on which iron oxide nanoparticles are formed combines the advantages of long carbon nanotubes and flat graphene surfaces. The high capacity over prolonged cycling achieved is due to the synergy between an electrically percolating networks of conductive graphene nanoribbons and the high lithium‐ion storage capability of iron oxide nanoparticles.