炭黑—相腈橡胶涂层复合材料的导电性能

将导电炭黑与丁腈橡胶混合制备导电聚合物复合材料,这种材料的电阻率随温度的变化呈正温度系数效应。讨论了不同的掺入炭黑粒子浓度,混炼和硫化及成膜溶剂对室温电阻率及ＰＴＣ效应的影响。     

炭黑-丁腈橡胶涂层复合材料的导电性能

将导电炭黑与丁腈橡胶混合制备导电聚合物复合材料,这种材料的电阻率随温度的变化呈正温度系数（ Ｐ Ｔ Ｃ）效应。讨论了不同的掺入炭黑粒子浓度、混炼和硫化及成膜溶剂对室温电阻率及 Ｐ Ｔ Ｃ效应的影响。     

导电SBS/SBR复合材料的研究

本文研究了碳黑填充ＳＢＳ／ＳＢＲ复合材料的基本电性能，对复合材料电阻率随温度的变化特性进行了详细研究。讨论了碳黑种类、结构和性质、填充浓度以及ＳＢＳ含量对复合材料电阻率和电阻——温度特性的影响。实验结果指出，碳黑（Ｎ５５０）／ＳＢＳ／ＳＢＲ（ＳＢＳＳＢＲ＝１１ｗｔ）复合材料的电阻率随温度的变化呈一定强度的正温度系数（ＰＴＣ）效应。     

导电SBS／SBR复合材料的研究

本文研究了碳黑填充充ＳＢＳ／ＳＢＲ复合材料的基本电性能，对复合材料电阻率随温度的变化特性进行了详细研究，讨论了碳黑种类，结构和性质，填充浓度以及ＳＢＳ含量对复合材料电阻率和电阻－温度特性的影响，实验结果指出，碳黑（Ｎ５５０）／ＳＢＳ／ＳＢＲ（ＳＢＳ：ＳＢＲ＝１：１ｗｔ）复合材料的电阻率随温度的变化呈一定温度的正温度系数（ＰＴＣ）效应。     

碳黑／聚烯烃导电复合材料PTC效应的稳定化

探讨了碳黑／聚烯烃导电复合材料ＰＴＣ效应产生与衰退的机理，认为要提高材料的ＰＴＣ效应与稳定性，在本质上必须控制导电粒子在聚合物基体中的分散程度与分布状态，并使其回复重现性提高。文中还详细讨论了提高ＰＴＣ效应稳定性的几种途径，为设计、制备现高性能的ＰＴＣ材料提供了科学依据。     

LDPE／炭黑复合导电材料PTC／NTC效应形成机理的探讨

本文从ＬＤＰＥ／炭黑复合导电材料的结晶性能出发，探讨了复合材料电阻率的正温度系数效应和负温度系数效应的形成机理，认为ＰＴＣ效应是由聚合物熔融时发生的晶相向非晶相的转变以及由此而产生的热膨胀共同引起，ＮＴＣ效应主要与炭黑粒子的附聚效应有关。     

聚合物基导电复合材料的热敏开关特性

聚合物基复合材料ＰＴＣ转变区的电阻率突变与渗流曲线在临界体积分数附近的电阻率突变在导电机制上是同一的。只要复合材料上有近似开关性质的渗流导电特性,室温下填料的体积分数决定ＰＴＣ转变温度及ＰＴＣ转变点的温度系数。     

新型有机PTC非线性导电材料及其器件的热电稳定性

提出了一种改善有机ＰＴＣ导电材料电性能重复稳定性的新途径，即在发热体材料中导入一种与碳黑粒子表面亲和性的极性接枝物作为第三组分，使其在界面形成一种所谓“束缚组成物”或“相互贯入型树脂组成物”使碳黑粒子大基体中分散稳定，实验表明，该法可以消除ＮＴＣ效应，提高电阻稳定性及ＰＴＣ强度，从基体与导电粒子表面相互作用的观点作了解释。     

电子束辐照对高密度聚乙烯/炭黑导电复合材料电阻率的影响

研究了电子束辐照固态和熔融态高密度聚乙烯／炭黑（ＨＤＰＥ／ＣＢ）导电复合材料的电性能随辐照温度和辐照剂量的变化。结果表明,对固态或熔融态辐照材料而言,其电阻率均随温度的升而而增大。等剂量下,固态辐照材料的ＰＴＣ强度比熔嘈态辐照的要高,两各状态经高剂量辐后其材料ＮＴＣ效应消失,,ＤＳＣ测试证明电阻率的２与基体的结晶行为以及交联链的形成密切相关。     

一种有机结晶物对丁腈橡胶/炭黑复合材料电性能的影响

将一种低分子量有机结晶物加入到丁腈橡胶/炭黑复合体系中制备导电复合材料。实验得出, 其电阻率随温度的变化呈不同强度的正温度系数(PTC) 效应。讨论了低分子量有机结晶物对复合材料室温电阻率及PTC 效应的影响。      

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。     

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。      

Fabrication process and electrical behavior of novel pressure-sensitive composites

A novel route was developed to fabricate a new pressure-sensitive composite by dispersing homogeneously conductive carbon particles in an insulating silicone rubber matrix. The composites showed a gradual change in electrical resistivity with applied pressure within percolation threshold region at a constant temperature. This type of gradual fall of resistivity with applied pressure is very important to fabricate pressure sensors. Various amounts of carbon particles were dispersed in a rubber matrix to understand the effect of volume fraction of conductive filler with applying external pressure on resistivity. A quantitative general effective media (GEM) theory was used to understand the resistivity of carbon–rubber composites system over a large range of volume fraction of carbon with applied pressure. The use of two different sizes of silicon rubber particles showed a significant effect in gradual fall of resistivity with applied pressure in the narrow range of percolation threshold. However, a large variation in resistivity from 1st measuring to 10th measuring was observed. A significant improvement in successive measuring of resistivity variation from 1st measuring to 10th measuring was observed when composites were fabricated in hexane solvent media. Finally, nano-sized Al₂O₃ was dispersed to control the resistivity variation upon successive measurement and to improve the mechanical properties of the composites. The material was suggested to use as unique materials as pressure sensors in practical applications mainly for robots.     

Control of the temperature coefficient of the DC resistivity in polymer-based composites

In this study, the roles of polymer matrices and filler additives in controlling the positive temperature coefficient (PTC)/negative temperature coefficient (NTC) behavior of DC resistivity at high temperature for semicrystalline ethylene vinyl acetate copolymer, amorphous acrylonitrile butadiene copolymer, and their blend composites filled with different carbon fillers like Conductex carbon black, Printex carbon black, and short carbon fiber have been investigated. It is seen that the PTC/NTC behavior of resistivity depends on the characteristics of both polymer matrices and filler additives. The anomaly in the results are due to polymer crystallinity, shape and size of fillers, and their thermal expansion coefficient, that play major role in controlling the PTC/NTC of resistivity at high temperature for the composites. Finally, reproducibility of composite resistivity has been evaluated with their some proposed practical applications. These composites can be used as both PTC and NTC thermistors.     

Mechanical and electrical properties of nanocomposites containing hybrid fillers of disk-like copper and conductive carbon black

Electrically conductive rubber (ECR) was prepared through conventional rubber mixing techniques on a two-roll mill, which the conductive filler was polymer-coated Cu nano-disk and conductive carbon black (CCB). The effect of Cu nanoparticles content on the mechanical and electrical resistivity properties of ECR was further investigated. The obtained results of six different compositions for ECR with 0, 5, 10, 15, 20 and 25 per hundred of rubber (phr) of Cu nanoparticles loading were compared. It was found that ECR has lower volume resistivity and high tensile strength, compared with rubber containing commercial Cu particles. These results suggest that when the Cu particles are nano-disk and surface modified, the mechanical and stability properties of the rubber can be synchronously improved.     

体积膨胀的稀释作用对聚合物基导电复合材料PTC效应的影响

聚合物基PTC复合材料中,导电填料的体积分数是一个绝缘体-导体的转换开关。理论分析表明,PTC转变区的电阻率突变与渗流曲线在临界体积分数附近的电阻率突变在导电机制上是同一的,聚合物基体体积膨胀的稀释作用对PTC效应有重要影响,在一定的温度范围内(小于PTC/NTC的转变温度),存在着定量的炭黑浓度稀释。      

Effect of Polyaniline Functionalized Carbon Nanotubes Addition on the Positive Temperature Coefficient Behavior of Carbon Black/High-Density Polyethylene Nanocomposites

The influence of addition of polyaniline functionalized multiwalled carbon nanotubes (PANI-MWNTs) on the positive temperature coefficient (PTC) characteristics of carbon black (CB) filled high-density polyethylene (HDPE) nanocomposite materials have been studied. Polymer nanocomposites were prepared by the combined solution and melt-mixing process. The experimental results showed that the PTC intensity and maximum resistivity of the hybrid nanocomposites were obviously influenced by the polyaniline functionalization of multiwalled carbon nanotubes (MWNTs). A noticeable PTC of resistivity was observed for PANI-MWNTs/CB/HDPE hybrid nanocomposites near the melting point of HDPE. This is due to the significant volume expansion near the melting point of the HDPE in presence of hybrid fillers and a sudden increase of the resistivity due to the disconnection of the conductive paths. The PTC effect of CB/HDPE composites can be effectively modified by the addition of PANI-MWNTs.     

PTC effect of carbon fiber filled EPDM rubber composite

Conductive ethylene-propylene-diene (EPDM) rubber composites filled with carbon fiber (CF) and carbon black (CB) were prepared by the conventional melt-mixing method. Optical microscope was used to observe the formation of the conductive pathways in the CF-filled composite. A model based on thermal expansion and electron tunneling theory was proposed to explain the PTC effect of CF-filled composite. The resistivity-temperature behavior of filled EPDM composites depended on the shape of carbonaceous fillers, CF/EPDM composite showed a positive temperature coefficient (PTC) effect, while CB/EPDM composite showed a negative temperature coefficient (NTC) effect.