高储能聚酰亚胺复合材料的介电性能研究

利用高性能聚酰亚胺树脂为基体材料,与不同组成、不同比例的BaTiO3粉末复合,制备了高密度复合绝缘材料,并研究了其电性能。研究发现随着BaTiO3含量的增加,复合材料电阻率下降,相对介电常数升高,介质损耗提高。所制备的试样介电常数超过了30,直流下击穿场强大于30MV／m。同时,介绍了高储能密度高分子复合材料在固体脉冲形成线方面的应用现状和发展。     

聚酰亚胺复合储能电介质材料研究进展

具有高击穿、低损耗、高柔性、低成本等优点的介电高分子材料在薄膜电容器产业中发挥着重要作用.然而,偏低的储能密度以及较差的热稳定性限制了其在高温工作环境中的应用.本文着重介绍了以聚酰亚胺为基体的介质储能材料及提高储能特性的研究方法,包括具有高介电常数、高绝缘特性的无机填料,多功能复合填料的结构和形貌对复合薄膜性能的影响以及界面微区特性的研究,并探讨了高温介质储能复合材料界面设计的未来研究方向.     

聚酰亚胺复合储能电介质材料研究进展

具有高击穿、低损耗、高柔性、低成本等优点的介电高分子材料在薄膜电容器产业中发挥着重要作用.然而,偏低的储能密度以及较差的热稳定性限制了其在高温工作环境中的应用.本文着重介绍了以聚酰亚胺为基体的介质储能材料及提高储能特性的研究方法,包括具有高介电常数、高绝缘特性的无机填料,多功能复合填料的结构和形貌对复合薄膜性能的影响以及界面微区特性的研究,并探讨了高温介质储能复合材料界面设计的未来研究方向.     

聚酰亚胺复合储能电介质材料研究进展

具有高击穿、低损耗、高柔性、低成本等优点的介电高分子材料在薄膜电容器产业中发挥着重要作用.然而,偏低的储能密度以及较差的热稳定性限制了其在高温工作环境中的应用.本文着重介绍了以聚酰亚胺为基体的介质储能材料及提高储能特性的研究方法,包括具有高介电常数、高绝缘特性的无机填料,多功能复合填料的结构和形貌对复合薄膜性能的影响以及界面微区特性的研究,并探讨了高温介质储能复合材料界面设计的未来研究方向.     

填料在共连续结构中选择性分散的功能与智能高分子材料的研究进展

综述了利用共连续亚微观结构和填料的选择性分散来设计和制备功能与智能高分子材料的最新研究成果。重点介绍了双连续结构的形成及其在介电绝缘材料、导电导热材料和形状记忆材料等体系中的应用。与"海-岛"结构相比,"双连续"结构中的两个组分都可以形成三维网络结构,因而都可看作基体相,有利于材料的力学、导电以及导热等性能的协同提高。通过控制功能性金属或无机填料在共连续结构中的选择性分散可以在很大范围内调节和优化材料的功能和智能特性,为设计和制备新型高分子纳米复合材料提供了新思路。     

活性炭基脱硫复合材料的制备

以成型活性炭为基体材料,采用浸渍吸附方法制备成型的氢氧化钠(NaOH)复合活性炭材料,分析成型活性炭的孔结构、NaOH溶液浓度以及浸渍时间对成型复合活性炭中碱负载量、孔结构和反复脱附一负载处理的影响.结果表明,高比表面积成型活性炭具有较好的反复吸附-脱附能力和稳定性,再生性能好.     

复合技术制备锂蓄电池相关材料

随着锂蓄电池技术的不断发展,更多的方法已应用于锂蓄电池电极材料及相关辅助材料的制备,复合技术是其中提高材料的性能和(或)降低成本的效方法之一。综述了最近几年来复合技术在制备锂蓄电池辅助材料方面的进展。这些辅助材料包括聚合物电解质、无机电解质、隔膜材料和正温度系数端子。其中聚合物电解质的复合包括加入无机填料和将无机基体与有机基体形成复合物,无机电解质的复合包括合成晶体电解质、玻璃态电解质、熔融盐电解质和聚合物盐中电解质。所得复合材料的性能均较单一材料的性能有明显提高,特别是晶体电解质,室温电导率可达2.17×10-3S/cm,可与非水液体电解质相媲美,而且具有良好的电化学和化学稳定性,可用于高压锂蓄电池。随着复合技术的不断发展,真正意义上的固态锂蓄电池的诞生为期不会太远,而且安全性能将会得到明显提高。     

正电性纳米层状材料对聚酰亚胺电性能的影响

二维纳米层状材料是改善聚合物电性能的重要填料。以对氨基苯甲酸为插层剂,利用离子交换制备了有机插层水滑石。以插层水滑石为纳米填料,通过原位聚合制备了水滑石/聚酰亚胺复合薄膜材料,研究具有正电性的水滑石层状材料对聚酰亚胺薄膜耐电晕性能的影响。结果表明:层板间的对氨基苯甲酸与聚合物的键合作用以及层板间聚合物分子链的增长,促进了水滑石在聚合物基体中的剥离分散;剥离后形成具有正电性的层状纳米片对复合材料的不同性能呈现不同的影响规律;层状纳米片能够提高复合薄膜的电气强度(增加了11%)和耐电晕时间(增加了4.7倍),同时能够增强和增韧复合材料。     

聚乙烯/氮化硼高导热复合材料的耐电弧性和介电性能

聚乙烯是一种重要的绝缘材料,但较低的热导率限制了其进一步应用。向聚乙烯基体中添加高导热无机颗粒可有效提高复合材料整体的热导率,同时会对其耐电弧性和介电性能产生影响。鉴于此,分别以微米氮化硼和微纳米混合氮化硼颗粒作为填料,制备了不同填料质量分数的两类聚乙烯/氮化硼复合材料。除了对各复合试样的热导率进行测量,还通过高压电弧起痕实验分析了各试样热导率对其耐电弧性的影响,最后对各试样的相对介电常数和交流击穿强度进行了评估。结果表明:当氮化硼填料的质量分数由0增加至40%,复合试样的热导率不断增大,耐电弧性随之增强。但是基体中填料质量分数较高时(20%),复合试样的相对介电常数明显增大、交流击穿强度显著下降。此外,基体中填料的质量分数相同时,微纳米混合氮化硼颗粒填充的复合试样具有更优异的导热性能、耐电弧性和介电性能。     

热电池阴极材料CoS_2制备及成型加工工艺现状

CoS_2材料由于电导率高、化学稳定性好和分解温度高而被认为是一种性能优异的热电池阴极材料。综述了CoS_2阴极材料的性质,主要的制备方法以及成型加工工艺,并对热电池阴极材料CoS_2的制备方法和国内成型加工工艺的发展方向进行了展望。     

碳纳米管填充的高介电常数聚合物基复合电介质材料

介绍了碳纳米管电性能及其功能化改性、以及利用碳纳米管掺杂聚合物制备柔性高介电常数复合材料的研究现状,发现化学气相沉积法得到的多壁碳纳米管(MWNT)在化学处理前后形成的聚合物基复合材料具有明显不同的分散特性和介电性能.相对于微米级球形导电颗粒填充的复合材料,一维尺度碳纳米管填充的复合材料具有明显低得多的渗流阈值,低渗流阈值可以明显保持聚合物基体优良的机械性能.期望在这一领域从工程电介质的角度做深入的研究工作,以发现碳纳米管在聚合物基复合材料领域所表现出的新特性、新现象.     

粉体颗粒状态对干压各向异性SrFe12O19永磁铁氧体性能的影响

采用预磁化、机械分散和熔融聚合物黏合剂处理铁氧体磁粉,研究了粉体颗粒状态对干压各向异性锶铁氧体磁性能的影响。结果表明,预磁化有利于提高磁粉颗粒的取向度;机械分散处理有助于减少乃至消除颗粒的团聚现象;采用熔融聚合物黏合剂不仅有利于磁粉颗粒在磁场作用下的充分取向,而且能提高磁体的致密度,得到了与湿压产品性能接近的干压各向异性锶铁氧体。     

FEATURE ARTICLE Conducting Polymer Composites

Conducting polymer composites become increasingly important for technical applications. In this article, the resulting electrical properties of such materials are illustrated by a variety of experimental examples. It is shown that the combined mechanical, thermal and electrical interaction between the filler particles via their electrical contacts and the surrounding polymer host matrix are responsible for the properties of the composite material. A short review is given of the theoretical background for the understanding of the electrical transport in such materials. The arrangement of the filler particles and the resulting conductivity can be described either by percolation or by effective medium theories. It can also be related to different types of charge carrier transport processes depending on the internal composite structure. Special emphasis is given to the microstructure of the filler particles such as size, hardness, shape and their electrical and thermal conductivities. A detailed analysis of the physics of the contact spots and the temperature development during current flow at the contact is given. It is shown that the polymer matrix has a strong influence on the electrical conductivity due to its elastic properties and the response to external thermal and mechanical stimulation. Strong changes in the electrical conductivity of conducting polymer composites can be realized either by thermal stimuli, leading to a positive and negative temperature coefficient in resistivity, or by applying mechanical stress. By using nonlinear fillers an additional degree of functionality can be achieved with conducting polymers.     

尼龙6粘结锶铁氧体永磁材料的制备与性能

以尼龙6和锶铁氧体磁粉为原料,采用热压成型工艺,制备各向同性粘结锶铁氧体永磁体。主要研究了原料的混合方式、磁粉的改性状态以及含量对材料磁性能(剩余磁通密度Br,内禀矫顽力Hcj,最大磁能积(BH)max)和力学性能(耐压强度Rc)的影响。结果表明,挤出造粒可以有效改善磁粉在尼龙6中的分散性,硅烷偶联剂的加入显著提高了磁体的力学性能。当未改性磁粉含量为90 wt%时,磁体具有良好的磁性能:Br=159 mT,Hcj=236 kA/m,(BH)_(max)=4.5 kJ/m~3,改性磁粉含量为85 wt%时,磁体的力学性能最佳(R_c=52.1 MPa)。     

Low loss flexible SrTiO<Subscript>3</Subscript>/POE dielectric composites for microwave application

Flexible, high dielectric constant and low dielectric loss composites for microwave application fabricated with SrTiO₃ (STO) ceramic filler dispersed inside a thermoplastic polyolefin elastomer (POE) polymer matrix have been studied in this paper. The dielectric property and the mechanical property of STO/POE composites filled with different volume fraction of ceramic filler were investigated. The results indicated that with the increase volume fraction of ceramic filler, both the permittivity and the dielectric loss of composites increased. Good frequency stability within a wide range was observed in all the samples. For the composites containing 40 vol% STO, the composites has a tensile strength of 2.75 MPa with an elongation of about 90% at break value. The permittivity and the dielectric loss of the composites were 11.0 and 0.01 in microwave frequency, respectively. A microstrip transmission line on the composites containing 40 vol% STO as a microwave substrate is designed and measured after bending at different angles, meanwhile the transmission coefficients of the microstrip transmission line were unchanged when bending angle is less than 60°. This indicates that the STO/POE composites have the promising characteristics for potential applications in microwave substrate, flexible dielectric waveguide and related flexible microwave devices.     

Ag/PVA纳米聚合物基复合材料的制备及其电性能研究

通过溶胶-凝胶法制备Ag/PVA纳米聚合物基复合材料，对复合材料的微观结构进行了表征，并对这种复合材料的电学性能进行了研究。结果表明，纳米银可以通过溶胶一凝胶法均匀分散在水溶性的PVA聚合物中，并且这种复合材料具有独特的电学性能，即在合适的纳米银含量时这种复合材料表现出高于其基体的电阻率和击穿场强，并且低温下这种现象更加显著，利用纳米金属粒子在绝缘体中的库仑阻塞效应对这些结果进行了解释。     

Multifunctional SrTiO3/NiZn ferrite/POE composites with eletromagnetic and flexible properties for RF applications

Multifunctional dielectric composites with electromagnetic and flexible properties for RF applications were investigated. A kind of low loss flexible dielectric and magnetic composite with SrTiO₃ (STO) ultrafine particles and NiZn ferrite (NZO) ultrafine particles embedded in a Thermoplastic Polyolefin Elastomer (POE) matrix was fabricated using the extrusion technology. The dielectric and magnetic properties of the as-prepared composites with different volume fraction of ceramic fillers were studied. The results indicate that when the volume of the ceramic fillers is fixed, the permittivity of the composites increase while the dielectric loss, permeability and magnetic loss decrease with the increasing of the ratio of STO to NZO. The cut-off frequencies of the composites are all above 1 GHz. The good frequency stability of the electromagnetic properties within a wide frequency range was observed. All the composites show very good flexibilities. With the increasing of the volume fraction of ceramic fillers, the tensile strength and elongation decrease. The obtained multifunctional flexible magnetic-dielectric composites are good candidates for the applications of the capacitor-inductor integrating devices in RF communications such as electromagnetic interference filters and antennas.     

Inorganic ceramic/polymer ferroelectric composite electrets

Ferroelectric composites are now an established alternative to conventional ferroelectric ceramic materials and to the more recently discovered ferroelectric polymers. These materials due to their unique blending of polymetric properties of mechanical flexibility, formability and low cost with high electro-active properties have been been suggested to be a viable alternative both in piezoelectric and pyroelectric transducer applications. This review is devoted to the piezoelectric and pyroelectric properties exhibited by these type of composites with a special reference to those made of ceramic particles embedded in a polymer matrix (i.e. 0-3 connectivity type composite). A review of models predicting the electro-active properties of 0-3 composites is presented together with a proposal for a new mixed connectivity cubes model to be applicable to the case of high ceramic loading and/or when the ceramic grain size incorporated in the polymer matrix is comparable to the thickness of the sample. A review of the experimental results of the piezo- and pyroelectric properties of various ferroelectric composite materials, reported by several workers, is also presented in this paper. Special reference is made to composites made from calcium modified lead titanate and poly(vinyldene fluoride-trifluorethylene) emphasizing their advantages in the poling process which is a critical phase in the process of obtaining successful electro-active 0-3 composite electrets     

碳纤维复合材料与金属的电偶腐蚀及防护

碳纤维增强树脂基复合材料具有比强度高、比模量高、耐疲劳性优良、性能可设计和易于整体成型等许多优异特性,已成功用于复合材料结构件中.本文从材料学的角度分析了碳纤维增强树脂基复合材料在与金属接触时发生的电偶腐蚀及防护问题,如电偶腐蚀的主要原因及反应历程、电偶腐蚀对碳纤维复合材料性能的影响及影响因素、电偶腐蚀的防护及相容性原则,可为复合材料结构件的设计、选材、成型、使用及贮存维护提供参考.     

文石型碳酸钙晶须及其复合体系介电性能的研究

研究了文石型碳酸钙晶须、轻质碳酸钙、钛酸钾晶须须及其填充聚丙烯（PP）和高密度聚乙烯（HDPE）复合体系的介电性能。粉体介电性能的测试采用了TR－10型电桥的粉末电极系统,复合体系介电性能的测量是将其制成片状试样后利用三电极系统进行的。通过实验表现,钛酸钾晶须由于晶体结构的不同而具有较损耗值。文石型碳酸钙晶须表面残留的MgCl2对介电性能有明显的影响,当使用去离子水将残留的MgCl2清除后,无论是粉体本身还是使用它的复合体系,介常数与介质损耗均有较大幅度的下降。