炭黑填充粒子对导电硅橡胶压阻特性的影响

阐述了复合型导电高分子材料的导电机理,分析了4种导电炭黑填充量对导电硅橡胶导电特性的影响,实验分析了相同导电填料、不同质量分数情况下的导电硅橡胶压阻特性,分析了相同质量分数、不同导电填料对复合材料压阻特性的影响。研究表明,随着炭黑填充量的不断增加,复合材料体积电阻率均呈下降趋势;4种炭黑填充的导电硅橡胶渗流阀值较接近;导电硅橡胶的电阻-压力变化规律符合隧道效应理论模型;为保证导电硅橡胶具有良好的压阻特性,应根据原料控制好导电炭黑的添加量。     

双导电相硅橡胶力敏材料的制备与电性能分析

为了获得具有较好压阻稳定性和重复性的力敏复合材料,在炭黑/硅橡胶复合体系中加入纳米氧化钌,完善补充导电相的同时加固硅橡胶交联网络。采用溶剂热还原法制备金属钌纳米颗粒,在空气中热氧化,得到尺寸为数十纳米的氧化钌颗粒;采用溶剂共混的方法制备炭黑/硅橡胶共混胶,用研磨分散的方法将纳米二氧化钌加入炭黑/硅橡胶共混胶中,硫化成型后得到氧化钌(RuO2)-炭黑(CB)/硅橡胶(MVQ)双导电相复合材料。采用自建的压阻性能测试系统测试了复合材料的压阻性能,测量结果表明,CB/MVQ体系中加入一定用量的RuO2其压阻重复性变好,压阻蠕变性得到改善;用扫描电镜、透射电子显微镜分析了复合材料的微观结构,并用能谱分析结合电子衍射图证明了纳米氧化钌以纳米结构存在于复合材料中,丰富和完善了炭黑导电网络,加固了硅橡胶交联网络,这些因素是导致压阻重复性提高的主要因素。     

填充炭黑对柔性触觉传感器用导电硅橡胶性能的影响

炭黑添加到绝缘的硅橡胶中,制备具有压阻特性的导电硅橡胶是触觉传感器常用的一种材料。通过实验研究3种填充炭黑制成的导电硅橡胶的渗流现象、相同体积分数时压阻特性。显示3种炭黑填充的导电硅橡胶具有不同的渗流阈值,同体积分数下的压阻特性也不相同。相同种类炭黑的添加量改变时,在渗流阈值附近导电硅橡胶的压阻特性最明显。利用扫描电镜(SEM)分析导电硅橡胶的断面形貌,表明导电硅橡胶性能与填料炭黑的分布有关,而炭黑的分布又与其结构相关:粒径越小、表观密度和比表面积越大的高结构炭黑分散性越好,导电硅橡胶的渗流阈值越小,相同体积分数下所获得压阻特性越显著。     

乙炔炭黑表面氧化改性及对硅橡胶压阻特性的影响

采用气相法和液相法分别对炭黑表面进行氧化预处理,通过傅里叶变换红外光谱仪、扫描电子显微镜能谱分析等分析手段对处理后炭黑的结构进行了表征,并将其填充到硅橡胶中制成导电橡胶复合材料。通过扫描电镜对试样进行形貌分析,并以压阻试验台测试了所制试样的压阻性能。实验结果表明,在橡胶基质中气相法处理的炭黑分散性好于液相法,结果与炭黑在水溶性基质中的分散性相反。在200℃通O2氧化1h得到的炭黑表面修饰的羟基、羧基等含量高,在硅橡胶中的分布均匀,处理后炭黑的填充导电橡胶电阻降低1个数量级,并且呈良好压阻特性,进一步提高了基于导电橡胶的柔性压力传感器的应用范围。     

炭黑填充型导电复合材料的压阻计算模型及实验验证

为研究新型传感器材料,在通用有效介质理论的基础上,提出了炭黑填充型导电复合材料的压阻特性数学计算模型,定量地得出炭黑颗粒的基本特征参数、体积分数和聚合物基体的弹性模量在复合材料压阻规律中的影响。分别以硅橡胶和高密度聚乙烯为基体相,三种不同粒径的炭黑为导电相,制备了炭黑填充型复合材料,对计算模型进行了实验验证。在炭黑颗粒分布均匀、炭黑体积分数在渗流阈值附近和外加压力≤2 MPa等三个边界条件下,数学计算模型与实验结果基本吻合,且压力-电阻变化规律一致。      

炭黑/硅橡胶导电复合材料微观结构及其导电特性

对炭黑/硅橡胶导电复合材料的微观结构及导电特性进行了研究。以液体硅橡胶为绝缘基体、纳米导电炭黑颗粒为填充材料制作的复合材料具有优良的导电特性,通过实验测试获得了不同炭黑含量下复合材料的电阻率,当炭黑质量分数4%时,可获得较好的导电性。利用电子扫描系统对炭黑颗粒在硅橡胶基体中的微观结构分布进行了观察,观察发现纳米炭黑颗粒主要以"团聚体"及与之相连的"链条"结构两种形式存在,并不是均匀规则的。将"团聚体"与"链条"结构简化为可变形的"大颗粒",在此基础上建立了相应的导电模型。     

炭黑/聚丙烯-聚(苯乙烯-乙烯/丁烯-苯乙烯)复合材料的介电性能和压阻性能

为了制备柔性较好的聚合物基压阻材料,利用熔融共混法制备了炭黑/聚丙烯-聚(苯乙烯-乙烯/丁烯-苯乙烯)(CB/PP-SEBS)复合材料,并研究了CB含量对CB/PP-SEBS复合材料介电性能和压阻性能的影响。结果表明:随着CB含量的增加,CB/PP-SEBS复合材料的介电常数、介电损耗及电导率均提高;CB/PP-SEBS复合材料发生导电逾渗时,CB的含量为12.2wt%;在CB/PP-SEBS复合材料发生弹性形变时,由于外力破坏了CB的导电网络,复合材料的电阻随着应变的增大而增大;循环压阻测试结果显示,在弹性变形区CB/PP-SEBS复合材料的电阻随着应变呈现周期性变化。研究结果可为制备具有稳定电阻变化的聚合物基压阻材料提供借鉴。     

流体作用下导电硅橡胶的压阻特性及弛豫特性

实验制备了不同导电硅橡胶试样,搭建了用于测试流体作用下导电硅橡胶压阻特性的试验平台并设计了测试方法,分别研究了在一定范围内液体静压下导电硅橡胶的体压阻特性、表面压阻特性、弛豫特性及在气压作用下的表面压阻特性。研究表明,在液体静压下,6%乙炔炭黑/2%纳米SiO2并用的试样所表现出的压阻性能最优,而纳米改性材料的添加与材料厚度的增大可以缩短导电硅橡胶的电阻弛豫时间;添加改性材料后,导电硅橡胶在气压作用下的压阻特性曲线明显优于单独添加乙炔炭黑的情况,而且随着材料厚度的增加其压阻特性有较好的提升。     

碳纳米管/炭黑/硅橡胶复合材料的压阻计算模型分析

以碳纳米管、炭黑为填料,硅橡胶为基体制备柔性压力敏感材料。将炭黑填充硅橡胶的压阻计算模型扩展应用于碳纳米管/炭黑/硅橡胶材料,研究了不同填料配比下的碳纳米管/炭黑/硅橡胶的渗流特性,并通过实验对计算模型进行了分析。结果表明,在碳纳米管/炭黑/硅橡胶体系中,选择适合的碳纳米管和炭黑组分配比,可获得较低的渗流阈值,且压阻实验结果与计算曲线偏差较小;由于碳纳米管和炭黑的协同效应和通用有效介质理论适用的边界条件,使得在碳纳米管/炭黑以一定的配比混合下,并用的导电填料体积分数略偏离阈值附近时,实验结果与计算模型曲线可以较好地吻合。     

炭黑的表面修饰及其对炭黑/硅橡胶导热性能的影响

通过采用羟基硅油对炭黑表面修饰, 改善炭黑与硅橡胶之间的相容性, 从而减小炭黑与硅橡胶界面热阻, 制备了高导热系数炭黑填充硅橡胶, 研究了炭黑填料与硅橡胶的相容性及炭黑/硅橡胶的导热系数。结果表明: 与原炭黑/硅橡胶体系相比, 经过羟基硅油修饰的炭黑与硅橡胶的相容性得到明显改善。当经表面修饰炭黑的质量分数为36.59%时, 表面修饰炭黑/硅橡胶的导热系数可达到0.591 W·(m·K)^-1, 较同含量未修饰炭黑/硅橡胶的导热系数高38.7%。     

A novel assembled carbon black/carbon nanotubes (CB/MWCNT) nano-structured composite for pressure-sensitive conductive silicon rubber (SR)

In this paper, a novel “grape string” carbon black/multi-wall carbon nanotubes (CB/MWCNT) structure was obtained by electro-static assembly method to enhance the resistance stability of the carbon material filled silicone rubber (SR). Carbon black (CB) and multi-wall carbon nanotubes (MWCNT) were surface modified by sulfonic dodecyl benzene sodium and cetyltrimethylammonium bromide to provide negatively charge and positively charge, respectively. Electric conductive sheet of CB/MWCNT/SR composite was obtained by mixing and vulcanizing. The assembly effect and dispersion state of the composites were analyzed by transmission electron microscopy and scanning electron microscopy. The electrical conductivity and dynamic pressure-resistance characteristic of CB/MWCNT/SR with different doping ratio and dosage were tested. The results show that the proper weight ratio 3:2 of CB:MWCNT for electrostatic assembly can cause the stable “grape string” nano-structure. The conductivity and pressure-resistance characteristic are superior when the volume fraction of “grape string” nano-composites reaches 22%, which will provided with less filler fraction and better stress sensitivity, compared with single component carbon black filler.     

Polyisoprene-multi wall carbon nanotube composite structure for flexible pressure sensor application

The major problem of conventional rigid sensor materials is difficulty to integer them into soft flexible structures. Piezoresistive polyisoprene/nanostructured carbon composite appears as promising materials for such application. Previous research approved high structure carbon black and carbon nanotube filled composites as finger pressure sensitive piezoresistive materials. Carbon nanotubes originate with variable length to width ratio and high electric conductivity in longitudinal direction of the tubes, which theoretically should make it possible to obtain electric percolation in polymercarbon nanotube composites at very low loads of filler. However recent experience with mechanically dispersed carbon nanotubes shows quite high values of percolation threshold and specific sensing properties. In this work we present an attempt to use ultrasound for improved dispersion of the filler in a piezoresistive polyisoprene-multi wall carbon nanotube composite as well polyisoprene-high structure carbon black composite. The noticeable shift of percolation threshold for both types of composites have been achieved. The piezoresistive behavior of sonicated composites have been determined and compared with mechanically mixed ones. The differences have been evaluated and explained.     

CB/PBO复合材料制备及吸波性能研究

以4, 6二氨基间苯二酚盐酸盐(DAR?2HCl)、对苯二甲酸(TPA)为原料, 合成TA盐, 再缩聚制得具有较高耐热性的聚对苯撑苯并二噁唑(PBO)。以PBO为基体, 炭黑(CB)为吸收剂, 热压法制备CB/PBO复合材料。对不同炭黑质量分数的复合材料介电及PBO基体与复合材料的热性能进行研究。结果表明, 随着炭黑含量的增加, 材料的复介电常数的实部与虚部均增大。含5%炭黑的试样厚度达到2 mm时, 吸波性能最好, 反射率小于-10 dB的带宽可达2.4 GHz, 最小反射率可达-32 dB。在空气中450℃保温5 h, PBO的质量损失为11.84%, 而5% CB/PBO复合材料的质量损失为21.99%。     

Silicone rubber nanocomposites containing a small amount of hybrid fillers with enhanced electrical sensitivity

A conductive silicone rubber (SR) composite, filled with both carbon nanotubes (CNTs) and carbon black (CB) is prepared by a simple ball milling method. Because of the good dispersion and synergistic effects of CNT and CB, the SR composite (SR with 2.5 phr CB and 1.0 phr CNT hybrid fillers) shows improvement in mechanical properties such as tensile strength and strain to failure. As well, due to the assembly of conductive pathways generated by the CNT and CB, the nanocomposite becomes highly conductive at a comparatively low concentration, with high sensitivity for tensile and compressive stress. Long-term measurement of properties shows that the SR composite maintains the excellent electrical properties under different strain histories. These outstanding properties show that the SR composite has potential applications in tensile and pressure sensors.     

凹凸棒粘土对炭黑/环氧复合材料电性能的影响

通过溶液混合法制备了凹凸棒(ATT)/炭黑(CB)/环氧树脂(EP)复合材料。使用紫外可见光光谱仪(UV-Vis)和Zeta电位测试仪对CB和(或)ATT在丙酮溶剂中的分散稳定性进行了研究。使用扫描电子显微镜(SEM)和电阻仪分别研究了不同填料比例以及含量对EP复合材料微观结构和电阻率的影响。结果表明,ATT的加入可以有效增强CB在溶剂中的分散稳定性并促进EP基体中导电网络的形成。当CB与ATT质量比为5∶1时,复合材料的电阻率比不添加ATT时下降了2个数量级;其渗流阈值(1%)(质量分数,下同)小于具有相同填料含量的CB/EP复合材料(1.8%)。最后探讨了ATT对CB/EP复合材料电性能影响的可能机理。     

Self-sensing piezoresistive cement composite loaded with carbon black particles

Strain sensors can be embedded in civil engineering infrastructures to perform real-time service life monitoring. Here, the sensing capability of piezoresistive cement-based composites loaded with carbon black (CB) particles is investigated. Several composite mixtures, with a CB filler loading up to 10% of binder mass, were mechanically tested under cyclic uniaxial compression, registering variations in electrical resistance as a function of deformation. The results show a reversible piezoresistive behaviour and a quasi-linear relation between the fractional change in resistivity and the compressive strain, in particular for those compositions with higher amount of CB. Gage factors of 30 and 24 were found for compositions containing 7 and 10% of binder mass, respectively. These findings suggest that the CB-cement composites may be a promising active material to monitor compressive strain in civil infrastructures such as concrete bridges and roadways.     

新型硅橡胶基压阻敏感复合材料制备及其性能研究

以多壁碳纳米管(MWNT)和纳米二氧化硅作为助填料,采用三辊研磨机制备了(MWNT-SiO2)/RTV复合材料,研究其压阻和介电性能.结果表明,纳米SiO2经KH570改性,其在基体中分散性及界面结合提高;(MWNT-SiO2)/RTV复合材料压力敏感性增强,当外界压力为150N时,含5％二氧化硅的复合材料相对电阻是M...