碳纤维增强木质复合材料电阻率-温度特性研究

介绍了碳纤维木质复合材料的制备及其电阻率测试方法,研究了不同掺量的碳纤维木质复合材料的电阻率随温度变化的规律。研究结果表明,碳纤维增强木质复合材料具有温敏特性,随着温度的升高,试件电阻率随温度的升高而下降,呈现NTC效应,而在相同温度条件下,电阻率随碳纤维含量的增加而下降。     

纳米导电纤维填充天然胶乳复合材料的电性能研究

用纳米导电纤维填充天然乳得复合材料,研究了复合材料的导电性、介电性以及温度对复合材料电阻率的影响。结果表明,随纳米导电纤维填充份数的增加,复合材料的电阻率下降,介常数增大;电阻率对温度的依赖性产大,并且当纳米导昵水在胶乳中形成导电网络时,电阻率和表面电阻率随温度同表现出不同的变化趋势。     

纳米导电纤维与导电炭黑填充PVC复合材料的电性能研究

对纳米导电纤维(nano-F)及导电炭黑（HG－CB）填充PCV复合材料的电性能进行了研究,当nano-F和HG－CB的填充量分别为20,10份时,复合材料的电阻率急剧下降,其用量继续增加,材料电阻率变化不大。nano-F填充复合材料在20－120℃范围内电阻率基本不变,具有高的电阻稳定性,HG－CB填充复合材料在20－60℃范围内随温度升高阻率逐渐增大,之后随温度继续升高电阻率开始下降,nano-F填充复合材料的伏安特性在不同温度下为欧姆线性关系,而HGC－CB填充复合材料的伏安特性比较复杂。     

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。     

炭纤维/ABS树脂复合材料的导电性研究

研究了炭纤维长度、填充量及表面处理条件下对炭纤维／ＡＢＳ树脂复合材料导电性的影响以及材料导电性同环境温度的相关性。结果表明复合材料的电阻率随着纤维填加量的增多而降低。纤维长度越长,复合材料导电性越好。纤维表面处理后,复合材料电阻率增大,相同纤维填充量下,表面处理时间越长,材料电阻率越大。温度对复合材料电阻率的影响随纤维填加量的增多而减少。而且,纤维表面状态的改变对复合材料的电阻率－温度关系有较大影响。     

2D SiC/SiC复合材料电阻率对服役环境的响应特性

研究针对不同服役环境下2DSiC/SiC复合材料的电阻率特性进行了研究。从1300℃降至室温的无氧环境中,复合材料的电阻率随温度降低而增大;借助曲线拟合,建立了电阻率与温度之间的映射关系。在1300℃空气环境中氧化20和60 h后,由于PyC界面层和SiC基体的氧化,复合材料的导电性显著降低;以SiO₂的含量定量表征氧化程度,建立了电阻率与氧化损伤之间的映射关系。复合材料的电阻率和应力随应变的变化趋势相似,电阻率变化率和刚度随应变的变化趋势相反。在线性阶段,基体开裂数量极少,刚度几乎不变,电阻率缓慢增大;在非线性阶段,基体开裂数量增加较快,造成刚度降低,电阻率快速增大;后半段的基体裂纹数量缓慢增多,刚度和电阻率变化率趋于平稳。     

隔离结构石墨烯-多壁碳纳米管/超高分子量聚乙烯导电复合材料阻温特性

以多壁碳纳米管(MWCNTs)及石墨烯(GNS)为填料,超高分子量聚乙烯(UHMWPE)为基体,采用溶液共混及模压工艺制备了具有隔离结构的混合填充导电复合材料。扫描电镜(SEM)和电阻率测试发现,MWCNTs、GNS形成的导电通路相互协作,填料的含量比对复合材料导电网络有明显的影响。复合材料的阻温特性曲线随填料含量比的变化而发生改变,当MWCNTs含量较高时(MWCNTs:GNS=3:1和1:1),复合材料的电阻率随温度升高而升高,在之后的降温过程中电阻率也逐渐升高;当GNS含量较高时(MWCNTs:GNS=1:3),复合材料的电阻率随温度升高而降低,降温过程中电阻率逐渐升高;经过热循环后复合材料的导电性能降低,此时复合材料中的隔离结构被破坏。     

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。      

一种压敏超导-金属-高分子复合材料

将高温超导材料YBa2Cu3O7 8与硅橡胶复合,制备了一种电阻对压力敏感的超导-高分子复合材料,并对不同温度下材料的物理性质进行了测量.结果表明这种材料的电阻率随压强的增加呈指数衰减,在10MPa压强作用下,材料的电阻率降低10个数量级,复合材料的电阻率及其对压强的敏感性随组分比例的不同而变化.研究发现这种超导-高分子复合材料的电阻率及其对压力的敏感性可以通过添加第3种金属组分来有效地调节;超导-金属-高分子复合材料的电阻率在150K以下有一个突然下降.     

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。      

Effect of Temperature on Electrical and Thermal Properties on Carbon Soot Filled Polyester Graded Composites

This article reports the development, DC conductivity behavior of carbon soot filled polyester graded composites. Carbon soot filled polyester composites having 3 wt% of carbon soot powder and polyester resin were prepared. DC conductivity measurements were conducted on the graded composites by using an electrometer in the temperature range of 28°C to 150°C. DC conductivity increased with increase in carbon soot concentration in the composites; DC conductivity increased with the increase in temperature. Activation energy was calculated by using Arrhenius equation for graded samples exhibited electronic conduction. Linear dependence of pre-exponential factors on activation energy for carbon soot filled polyester graded composites reveals semi-conducting behavior of the composites.     

C/C密度梯度材料的热学及力学性能研究

C/C密度梯度材料的研究在国内尚属于空白,本文作者研究了C/C复合材料的导热系数与密度间的关系,并对比密度均匀材料与密度梯度材料的导热系数和力学性能,从理论上探索C/C密度梯度材料的应用前景。为进一步开发C/C密度梯度材料提供了理论依据。     

SiO2纳米粉对炭黑／硅橡胶复合材料的压阻,阻温特性的影响

研究了添加导电炭黑和ＳｉＯ２纳米粉的硅橡胶复合材料的导电机理、压阻及阻温效应。发现：添加１５ｇ导电炭黑的硅橡胶（硅橡胶为１００ｇ，下同）的压阻效应，随着纳米Ｓｉ２量的增加显著提高。在一定压力范围内，电阻随压力增加而呈线性增加。只添加１５ｇ导电炭黑的硅橡胶材料的电阻率随温度升高而略为降低，而加入纳米级气相法生产的ＳｉＯ２的炭黑／硅橡胶复合材料的电阻随温度增加而增加。且其导电机制为欧姆导电。其电导率受     

碳纤维增强铜基复合材料的性能研究

采用粉末冶金法制备了短碳纤维增强铜基复合材料。经对不同碳纤维含量试样的硬度及导电性能的测定，并在干摩擦的条件下研究了碳纤维增强铜基复合材料的摩擦磨损性能，同时对磨损表面的微观结构进行观察来分析其磨损机理。实验结果表明，随着碳纤维含量的增加，该材料的硬度和耐磨性均有所增加，但其导电性有所下降。     

PAN-based carbon fibers/PMMA composites: thermal, dielectric, and DC electrical properties

The study deals with thermal, dielectric, and DC electrical properties of polyacrylonitrile (PAN)-based carbon fibers/poly(methyl methacrylate) composites. The polymer composites contain 0, 5, 10, 20 and 30 wt.% PAN-based carbon fibers. The thermal conductivity was studied as a function of filler content and temperature. It was found that the thermal conductivity is enhanced by addition of carbon fibers concentration and temperature. The dielectric properties were determined using impedance measurements. The results showed that the dielectric constant and dielectric loss are decreased with frequency, and increased with both temperature and fibers content. The DC electrical conductivity, temperature coefficient of resistance, and activation energy were studied as a function of fibers concentration in the temperature ranges 30–110?°C. It was found that the composites exhibit negative temperature coefficient of resistivity and enhancement of electrical conductivity with increasing temperature and carbon fibers concentration. The observed increase in the DC conductivity was explained according to the approach of conductive paths and connections between the carbon fibers.     

The electrical behavior of laminated conductive polymer composite at low temperatures

The study deals with the electrical characteristics of laminated conductive polymer composites consisting of epoxy and carbon fibers with different concentration. The composites contain 7, 17.5, and 25.2 wt% carbon fibers (10, 25, and 36 layers of carbon fibers), respectively. The DC electrical conductivity was studied as a function of filler concentration in low temperature range 25–275 K. It was found that the composites exhibit negative temperature coefficient of resistivity (TCR) and electrical conductivity enhancement with temperature and carbon fibers concentration. The semiconducting behavior of the observed electrical conductivity is characterized by two different regions: high temperature range where the conductivity increases gradually (thermal process) and low temperature range where the conductivity increases with a less rate (Motts hopping process) with increasing of temperature.     

碳/碳复合材料的热物理性能和抗热震性的研究

本文用激光脉冲法、石英示差法和激光扫描法研究测量了室温至2000℃碳/碳复合材料的热物理性能,包括导热系数和热膨胀系数。通过抗热震系数研究分析了三向细编碳/碳复合材料和碳布两向增强碳/碳复合材料的抗热震性。研究了温度、密度和取向等对碳/碳复合材料的热物理性能和抗热震性的影响。      

碳/环氧薄壁豆荚杆热-结构性能试验研究

碳纤维增强环氧树脂基复合材料成功应用于航天器结构,其热-结构效应是重点关注问题之一。该文以碳纤维增强环氧树脂基复合材料空间可展天线薄壁豆荚杆为研究对象,通过试验对其材料热物理参数进行测定,得到材料的热物理参数,测得其比热容和导热系数均随着温度升高而增大,符合材料热参数的变化规律。采用大体积真空罐、热沉和红外加热笼模拟空间热环境,对薄壁豆荚杆进行真空热辐射试验,得到试件特征位置处的瞬态、稳态温度场,并采用低温应变片测试特征点应变时程,分析得到薄壁豆荚杆在热辐射作用下纵向、横向及薄壁内外两侧热响应的温度和应变分布规律,为理论分析、数值研究和设计提供参考。     

Direct current conductivity of carbon nanofiber-based conductive polymer composites: effects of temperature and electric field

Polymer composites based on high density polyethylene (HDPE) and carbon nanofiber (CNF) were fabricated by melt compounding. The dependences of electrical conductivity of HDPE-CNF composites on filler concentration, temperature, and applied electric field were investigated. The results showed that the conductivity of the HDPE-CNF composites follows the scaling law of percolation theory. Increasing temperature caused a sharp increase in the resistivity of HDPE-CNF composites near the melting temperature of HDPE, yielding a positive temperature coefficient (PTC) effect of resistance. The potential mechanisms involved in the PTC effect of such composites were analyzed. An investigation of the effect of electric field on the conductivity of HDPE-CNF composites revealed the presence of tunneling conduction. The tunneling conductivity increased with increasing filler content because of high tunneling frequency, and decreased with rising temperature as a result of gap widening between conducting CNF fillers.