导电硅橡胶复合材料的制备及其应变传感行为的研究

发布时间：2018-03-22 10:40

本文选题：导电高分子复合材料　切入点：拉伸应变传感　出处：《北京化工大学》2016年硕士论文　论文类型：学位论文

【摘要】：用于应变传感器的导电高分子复合材料(CPCs)已得到广泛研究。不同应用中需要大范围的应变灵敏度和高的重复性。本课题中,我们在甲基乙烯基硅橡胶(PMVS)中填充碳纳米管(CNTA)和炭黑(CB)制得了导电复合材料,并系统研究了导电填料网络、复合材料应变传感行为和疲劳周期下电性能稳定性的关系。我们研究了填料用量和体积配比对填料导电网络、复合材料应变传感行为和电性能稳定性的影响,并试图制备出一种兼具高灵敏度、重复性和疲劳周期下电性能稳定性的导电复合材料。首先,我们选定刚开始逾渗时1.5vo1.%,逾渗快结束时3vo1.%和远超过逾渗区6vo1.%三个关键填料用量作为参考对象,并变换炭黑与碳纳米管的体积配比(VCNTA/VCB=0:10,4：6,10：0),研究了形成的导电复合材料的导电性能和力学性能。我们发现所有复合材料的断裂伸长率均能达到78%以上,说明复合材料在用于应变传感时能承受较大应变。通过橡胶加工分析仪(RPA)和电镜对硅橡胶基体中填料的网络进行了表征,说明了复合材料导电性能随填料体积分数和不同填料体积配比变化的原因。我们发现,随着填料体积分数及VCNTA/VCB的增加,复合材料的电阻-应变灵敏度降低；随着填料体积分数的增加,复合材料应变传感行为的重复性及疲劳周期下的电性能稳定性提高。无论是硅橡胶基体中填充颗粒状还是纤维状的填料,填料含量在逾渗值附近,复合材料的电阻-应变灵敏‘度都是最高的,而复合材料应变传感行为的重复性及疲劳周期下的电性能稳定性是最差的；填料含量远超逾渗值,情况则恰恰相反。由于碳纳米管的长径比较大,相同填料含量下CNTA/PMVS复合材料比CB/PMVS复合材料的电性能好,但是CNTA/PMVS复合材料疲劳周期下的电性能稳定性是最差的。所以依赖单一的碳纳米管或者炭黑网络很难同时获得高的灵敏度、重复性和电性能稳定性。填料体积分数为3vo1.%的CNTA/CB/PMVS复合材料同时表现出高灵敏度(60%的应变下应变系数GF为10),高重复性(max R/R0的相对标准偏差为3.58%),高的疲劳周期下的电性能稳定性(R/R0值的范围为1.62到1.82),这是由于碳纳米管和炭黑的双导电网络的协同效应。由于复合材料中碳纳米管和炭黑的体积分数刚刚超过其逾渗阈值,硅橡胶基体中炭黑、碳纳米管分别形成导电网络以构成双导电网络。即使应变下发生导电网络的破坏-重建,导电网络仍可以形成,从而复合材料表现出高重复性和电性能稳定性。
[Abstract]:Conductive polymer composites for strain sensors have been extensively studied. Wide range strain sensitivity and high reproducibility are required in different applications. We prepared conductive composites by filling carbon nanotubes (CNTAs) and carbon black (CBB) in methyl vinyl silicone rubber (PMVSs), and systematically studied the conductive filler networks. The relationship between strain sensing behavior of composite materials and electrical property stability under fatigue cycle. The effects of filler content and volume ratio on filler conductive network, strain sensing behavior and electrical property stability of composites were studied. We also try to fabricate a kind of conductive composite with high sensitivity, repeatability and fatigue cycle. We selected three key fillers as reference: at the beginning of percolation at the beginning of percolation, at the end of percolation at 3vo1.% and well above the percolation zone by 6vo1.%. The volume ratio of carbon black to carbon nanotubes was also changed. The conductivity and mechanical properties of the resulting conductive composites were studied by VCNTA / VCB0: 10: 4: 6: 10: 0. We found that the elongation at break of all the composites could reach more than 78%. The results show that the composite can withstand large strain when it is used for strain sensing. The network of filler in silicone rubber matrix is characterized by rubber processing analyzer (RPA) and electron microscope. It is found that the electrical conductivity of the composites varies with the volume fraction of the filler and the volume ratio of the different fillers. We find that the resistance strain sensitivity of the composites decreases with the increase of the volume fraction of the filler and the increase of VCNTA/VCB. With the increase of the volume fraction of filler, the repeatability of strain sensing behavior and the electrical property stability under fatigue cycle of composites are improved. Whether the filler is filled with granular or fibrous filler in silicone rubber matrix, the filler content is near the percolation value. The resistance-strain sensitivity of composites is the highest, while the repeatability of strain sensing behavior and the stability of electrical properties under fatigue cycle are the worst, and the filler content far exceeds the percolation value. The opposite is true. Because of the large length and diameter of carbon nanotubes, CNTA/PMVS composites with the same filler content have better electrical properties than CB/PMVS composites. But the electrical stability of CNTA/PMVS composites during fatigue cycles is the worst, so it is difficult to obtain high sensitivity simultaneously by relying on a single carbon nanotube or carbon black network. Reproducibility and electrical property stability. The CNTA/CB/PMVS composites with 3 vo1% filler volume fraction also showed high sensitivity of 60% strain strain coefficient GF was 10%, the relative standard deviation of high repeatability max R/R0 was 3.58%, and the electrical property under high fatigue cycle. The range of R / R 0 is from 1.62 to 1.82, which is due to the synergistic effect of carbon nanotubes and carbon black double conductive networks, since the volume fraction of carbon nanotubes and carbon black in composite materials has just exceeded its percolation threshold. Carbon black and carbon nanotubes in silicone rubber matrix form conductive networks to form double conductive networks. Thus the composite exhibits high reproducibility and electrical stability.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ333.93;TB332

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