炭黑填充型导电复合材料的聚集体结构模型

分析了炭黑填充聚合物导电复合材料的非线性导电行为和机理,基于有效介质理论及以炭黑聚集体的等效球形单元为基本单元,建立了描述其非线性导电行为的聚集体结构模型。进而推导出复合体系导电率与炭黑体积分数之间的关系式及其逾渗阈值的计算式,克服了有效介质理论只能得到逾渗阈值为1/3而不能解释低于1/3的逾渗阈值的不足。应用这些表达式预测了导电复合体系的导电率和逾渗阈值,并与实验结果进行了比较,结果表明:预测值与实验结果有较好的一致性。     

Electrical conductivity of polyethylene-carbon-fibre composites mixed with carbon black

The study of electrical conductivity of high-density polyethylene-carbon-fibre composites mixed with different concentrations of carbon black is reported. The influence of the mixing procedure of the additives and material preparation is examined with regard to the conductivity values. The use of these two filler types in polyethylene composites combines the conducting features of both. Thus, while fibres provide charge transport over large distances (several millimetres), carbon black particles improve the interfibre contacts. Results are discussed with reference to simple electrical models. It is shown that for composites in which the segregated carbon black-polyethylene component lies above the percolation threshold the electrical interfibre contacts are activated through carbon black particle bridges, leading to a conductivity rise. This effect is more relevant in the case of shorter fibres. Processing of the material involving fibre orientation, such as in injection-moulding, decreases drastically the conductivity level reached.     

低压缩永久变形导电炭黑/硅橡胶复合材料的制备与性能

为获得一种低压缩、永久变形及高回弹的导电屏蔽硅橡胶密封材料,以经偶联剂表面处理的炭黑作补强剂及导电填料,乙烯基硅橡胶生胶作基料,制备出一种导电炭黑/硅橡胶复合材料。研究了不同炭黑含量的导电炭黑/硅橡胶复合材料的力学性能、弹性、分散性以及电性能,采用SEM观察了炭黑在硅橡胶基体中的分布形貌,分析了导电炭黑/硅橡胶复合材料的导电机制及屏蔽机制。结果表明:随着炭黑含量的增加,导电炭黑/硅橡胶复合材料的Shore A硬度由31增至70;拉伸强度先由3.31 MPa增至5.28 MPa,而后趋于稳定;拉断伸长率先由198%增至297%,然后再减小至210%;恒定压缩永久变形量先减小后增大,瞬间回弹率逐渐减小;由于"炭黑簇"的形成及导电通路的完善,导电炭黑/硅橡胶复合材料的导电性能及屏蔽效能增强。     

Electrical and morphological studies of polymeric composites based on carbon black

Conventional polymers, polypropylene and polystyrene, containing carbon black as conductor additive, were prepared. Impedance complex-plane analysis is used in order to characterize the composites obtained. Microstructure studies indicate that carbon black affects the size but not the geometrical morphology. The electrical conductivity of polypropylene composites is higher than polystyrene, and is correlated to the microstructural and wettability properties of these polymer matrices.     

聚苯胺/乙炔炭黑多孔复合材料的制备及性能研究

以纳米乙炔炭黑在反应体系中的聚集体为模板,采用化学氧化法制备了多孔形貌的聚苯胺。讨论了乙炔炭黑经硝酸液相氧化处理对聚苯胺/炭黑复合材料形貌、导电性及热性能的影响。研究结果表明,在聚苯胺掺杂酸盐酸用量增加到80mL时两种复合材料都具有多孔结构,并且由于炭黑经硝酸液相氧化后分散性及表面性质得到改善,产物呈现出明显的一维线性结构,该复合材料电导率高达5.55S/cm。多孔复合材料热分解温度均在430℃左右。     

DC electrical conductivity of poly(methyl methacrylate)/carbon black composites at low temperatures

The study deals with the dc electrical conduction of poly(methyl methacrylate)/carbon black composites of different carbon black (CB) filler concentrations (2, 6, 12 wt%). The dc electrical conductivity was studied as a function of filler concentration, and temperature in the range (20–290 K). It was found that the composites exhibit negative temperature coefficient of resistivity (NTCR) at low temperatures and enhancement in the dc electrical conductivity with both temperature and CB concentration. The observed increase of conductivity with CB concentration was interpreted through the percolation theory. The dependence of the electrical conductivity of the composites in low temperatures was analyzed in term of a formula in consistence with Mott variable rang hopping (VRH) mechanism. The observed overall mechanism of electrical conduction has been related to the transfer of electrons through the carbon black aggregations distributed in the polymer matrix.     

原位聚合法制备炭黑/聚甲基丙烯酸酯导电复合材料

通过原位聚合法制备了炭黑/聚甲基丙烯酸甲酯(CB/PMMA)、炭黑/聚甲基丙烯酸丁酯(CB/PB-MA)和炭黑/聚甲基丙烯酸2-乙基己酯(CB/PEHMA)三种导电复合材料,研究了这三种聚合物基体对复合材料的导电性影响。结果表明:由于炭黑的阻聚作用,当复合材料的炭黑含量增加时,均聚物的数均分子量呈下降趋势,多分散性系数PDI变大。而且炭黑粒子表面发生了接枝聚合反应,这有利于炭黑粒子在聚合物基体中的分散。当聚合物基体的玻璃化温度Tg较高时,复合材料逾渗阈值较低。     

PAN／Ni－P纤维和碳黑填充的HIPS复合材料的导电性

研究经化学镀镍的聚丙烯腈（ＰＡＮ）导电纤维（ＰＡＮ／Ｎｉ－Ｐ）填充的高抗冲聚苯乙烯（ＨＩＰＳ）复合材料的导电性与导电填料浓度的关系及加入有机钛酸酯偶联剂的影响、为了进一步提高复合材料的导电性，在ＰＡＮ／Ｎｉ－Ｐ纤维填充的复合材料中又加入不同量的碳黑，由于碳黑粒子的加入改善了纤维间的接触状态，更有利于导电网络的形成，从而大大提高了复合材料的导电能力。     

聚乙烯/炭黑/碳纤维复合材料阻温特性

研究了碳纤维对聚乙烯/炭黑复合材料阻温特性的影响,并对导电机理做初步的探讨。由于碳纤维远程导电效应的存在,随着碳纤维含量的增加,复合材料PTC强度增加,PTC转变区域变窄,PTC转变温度移向高温,还有助于提高复合材料的电性能稳定性。      

Pressure-sensitive electrically conductive nitrile rubber composites filled with particulate carbon black and short carbon fibre

The electrical conductivity of pressure-sensitive nitrile rubber composites, containing different loadings of particulate carbon black filler and short carbon fibre, have been studied. The conductivity of composites increases with increasing of filler concentration as well as with increased applied pressure up to a certain limit. The composites containing particulate fillers register low conductivity as compared to composites containing short carbon fibres, due to easy formation of an interconnecting network in the latter case. The effect of the orientation of short carbon fibre with respect to an applied electric field has also been studied. The pressure dependence of composites with transversely oriented carbon fibres with respect to electric fields is higher than that of composites with longitudinally oriented carbon fibres. The results are interpreted on the basis of the formation of interconnecting continuous conducting networks.     

Low temperature electrical conductivity of low-density polyethylene/carbon black composites

The study deals with the electrical characteristics of carbon black/low-density polyethylene (CB/LDPE) composites of various CB filler concentrations (10, 15, and 20 wt.%). The DC electrical conductivity was studied as a function of filler concentration in low temperature range 25–285 K. It was found that the composites exhibit negative temperature coefficient of resistivity (TCR) at low temperatures and high enhancement in the electrical conductivity with both temperature and carbon black concentration. The observed increase of conductivity with the filler concentration was interpreted through the percolation theory. The dependence of the electrical conductivity of the given composites on temperature (25–285 K) was analyzed in terms of a formula in consistence with Mott hopping mechanism.Visiting scientist from the Jordan University of Science and Technology, Irbid-Jordan.     

导电炭黑填充硅橡胶的电阻温度系数

以炭黑(CB3100)为导电相,硅橡胶为基质制备导电复合材料。研究导电橡胶中炭黑质量分数对电阻温度系数的影响,并用填料对电阻温度系数的影响。以隧道效应理论为基础,给出了导电炭黑填充橡胶的电阻温度系数计算模型,结合实验得到温度对导电炭黑/硅橡胶电阻温度系数的影响主要体现在对其电阻率的影响;基体的体积热膨胀提高复合材料的电阻率,提高了正电阻温度系数;炭黑粒子间的隧道效应降低复合材料的电阻率,增强了负电阻温度系数;在炭黑/硅橡胶中加入少量碳纳米管,利用碳纳米管和炭黑的协同补强效应,使复合材料的导电性和稳定性提高。     

石墨/酚醛树脂复合材料双极板的制备与性能

双极板是质子交换膜燃料电池的重要组成部分,石墨与聚合物的复合材料双极板是目前研究的重要方向。采用模压热固化二步法,以酚醛树脂为粘结剂、天然鳞片石墨为导电骨料、炭黑为添加剂制备了质子交换膜燃料电池用复合材料双极板。系统研究了不同种类石墨对石墨/酚醛树脂复合材料电性能和抗弯强度的影响。结果表明:以天然鳞片石墨为导电原料时,所制备的石墨/酚醛树脂双极板的性能最好;添加导电炭黑能有效提高石墨/酚醛树脂复合材料的电导率;在复合材料制备中加入4wt%的碳纤维,碳纤维-石墨/酚醛树脂复合材料的抗弯强度提高了29%;碳纤维表面液相氧化处理能有效提高纤维与基体间的结合强度,随着处理时间的延长与处理温度的升高,碳纤维-石墨/酚醛树脂复合材料的电导率和抗弯强度都有很大程度的提高;最终固化温度主要影响酚醛树脂的交联程度,随着最终固化温度的升高,酚醛树脂的交联程度增加,电导率增大,但抗弯强度有一定程度减小。     

锂二次电池正极--聚苯胺/炭黑导电复合材料的制备与表征

用导电炭黑（C）吸附聚合工艺,以三氯化铁（FeCl3）为氧化剂,在盐酸（HCl）环境中制备聚苯胺/炭黑（PAn/C）导电复合材料.研究了反应时间、氧化剂用量、炭黑用量对复合材料电导率和产率的影响,探讨了炭黑吸附聚合对复合材料颗粒形态和堆积密度的改进以及聚苯胺复合正极膜作锂二次电池正极的电化学性能的影响,运用红外光谱（FT-IR）、SEM、四探针及电化学测试仪对其进行了测试和表征.     

炭黑吸附聚合制备聚吡咯/ 炭黑导电复合材料

用炭黑吸附化学氧化聚合法制备聚吡咯/ 炭黑( PPy/ C) 导电复合材料。运用FT2IR、TGA、SEM、四探针和电化学测试仪对材料的组成、结构和性能进行了测试和表征。导电炭黑的加入不仅提高了材料的电导率,由原来的6.152 S/ cm 增加至13.42 S/ cm, 而且提高了材料的堆积密度, 改善了聚吡咯的颗粒形态和制膜加工性能, 聚吡咯复合材料为正极的锂/ 聚吡咯二次电池的性能得以改善, 室温下充放电循环30 次以上, 电池容量无明显衰减, 库仑效率在98 %以上, 首次放电容量以聚吡咯计可达41 mAh/ g。      

炭黑/聚合物复合材料的研究进展

综述了炭黑／聚合物复合材料的研究进展。该类复合材料主要是通过共混、接枝、沉积、聚合制备的。讨论了聚合物结构、分子量及表面张力对炭黑填充的聚合物及共混物的导电性和物理性质的影响，以及用不同聚合方法制备炭黑／聚合物复合材料。着重讨论了如何获得低渗流阈的炭黑填充的导电复合材料及制备聚合物为壳，炭黑为核的核壳材料。     

Computer simulation of electrical conductivity of graphite-based polypropylene composites based on digital image analysis

The electrical conductivity of polypropylene/graphite (PP/G) composites and polypropylene/graphite/carbon black (PP/G/CB) composites was investigated in this article. A simulation procedure, which is not limited to any specific parameters (i.e. graphite size and shape), was used to numerically compute the electrical conductivity of the composites. The simulations were carried out using a 2D finite element program based on the digital image analysis. The simulation results were in good agreement with the experimental conductivity values even though there were several limitations in using digital image analysis such as sampling, sample preparation, the quality of the image and the choice of the threshold. The microstructures of the surfaces of the composites were observed using scanning electron microscopy (SEM).     

Microstructural image analysis and structure–electrical conductivity relationship of single- and multiple-filler conductive composites

The electrical conductivity of polypropylene/graphite (PP/G) composites and polypropylene/graphite/carbon black (PP/G/CB) was investigated in this paper. The conductivity experimental data of PP/G composites was correlated to theoretical models, which exist in the literature, and the results showed higher values of the exponent t compared to the expected typical values. Moreover, these analytical models were unable to describe the electrical behaviour for multiple-filler conductive composites such as PP/G/CB composites. A 2D computer simulation to numerically compute the electrical conductivity based on digital image analysis was found to be somewhat useful to describe the mechanism of conduction in PP/G/CB composites and to determine the critical factors in developing high electrically conductive composites.     

Effect of different carbon fillers and dopant acids on electrical properties of polyaniline nanocomposites

Electrically conducting nanocomposites of polyaniline (PANI) with carbon-based fillers have evinced considerable interest for various applications such as rechargeable batteries, microelectronics, sensors, electrochromic displays and light-emitting and photovoltaic devices. The nature of both the carbon filler and the dopant acid can significantly influence the conductivity of these nanocomposites. This paper describes the effects of carbon fillers like carbon black (CB), graphite (GR) and muti-walled carbon nanotubes (MWCNT) and of dopant acids like methane sulfonic acid (MSA), camphor sulfonic acid (CSA), hydrochloric acid (HCl) and sulfuric acid (H₂SO₄) on the electrical conductivity of PANI. The morphological, structural and electrical properties of neat PANI and carbon–PANI nanocomposites were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT–IR), UV–Vis spectroscopy and the four-point probe technique, respectively. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies were also conducted for different PANI composites. The results show that PANI and carbon–PANI composites with organic acid dopants show good thermal stability and higher electrical conductivity than those with inorganic acid dopants. Also, carbon–PANI composites generally show higher electrical conductivity than neat PANI, with highest conductivities for PANI–CNT composites. Thus, in essence, PANI–CNT composites prepared using organic acid dopants are most suitable for conducting applications.     

Effects of hybrid carbon fillers of polymer composite bipolar plates on the performance of direct methanol fuel cells

The effects of carbon filler type on the properties and performance of composite bipolar plates fabricated by compression molding of carbon fillers such as graphite, carbon black (CB), multi-walled carbon nanotube (MWNT), carbon fiber (CF) and powder type epoxy have been investigated. The electrical conductivity and flexural properties of the composites are increased by increasing the content of fibrous conducting fillers, e.g. MWNT and CF. On the contrary, incorporation of particulate fillers such as CB and graphite plays a significant role in enhancing the electrical conductivity but has a negative effect on the flexural properties of the composites. The current–voltage curve of the fuel cell indicates that the performance of the fuel cell is improved upon selection of an optimum amount of carbon filler in the composite bipolar plates.