导电高分子复合材料微观结构调控及其应力响应性能研究
发布时间:2018-04-25 23:24
本文选题:导电高分子复合材料 + 裂纹-褶皱结构 ; 参考:《郑州大学》2017年硕士论文
【摘要】:导电高分子复合材料(Conductive polymer composites,CPCs)是由导电填料填充高分子材料基体复合制备而成。CPCs广泛用于自控温加热材料、传感器、电磁屏蔽、抗静电材料等,引起了研究者的广泛关注。CPCs在应力、温度、气体、液体等外场的作用下,表现出丰富的响应行为。其中,由于CPCs在拉伸应力场中所表现出敏感的响应行为,其在运动检测装置、可穿戴应变传感器、柔性电子皮肤等领域受到越来越广泛的关注。虽然CPCs基应力敏感材料拥有十分优异的特性(如易加工、成本低等),但其性能仍有许多不足亟需解决,如CPCs在循环应力场中出现的滞后效应以及重复性差等,这极大的限制了CPCs的应用空间。因此构建新型的高分子材料结构对CPCs的性能进行调控具有十分重要的意义。在柔性应变传感器领域,CPCs的响应性能,如灵敏度、重复性等性能的调控至关重要。研究显示,裂纹式应变传感器具有较高的响应性能,但响应范围有限;褶皱式应变传感材料响应稳定性优异,但灵敏度不高。本文设计了兼具裂纹-褶皱的微观结构,基于兼具裂纹-褶皱的特殊结构,制备了GNPs/TPU/PDMS柔性力敏复合材料。这种新型的裂纹-褶皱结构通过对材料进行压力拖曳产生。褶皱结构在GNPs层中分布较均匀,裂纹在褶皱结构上有所分布且与褶皱结构取向方向相同。对应变传感器在拉伸作用下的电学性能的研究发现,该传感器的GF可达到150并在较大的应变范围(0%~20%)内保持稳定。通过材料的形貌分析,观察到了复合材料受拉伸作用时裂纹的变化,基于裂纹扩展及回复机制探讨了裂纹开闭对复合材料力敏响应性能的影响。该传感器能准确测量小应变(应变0.1%),且响应速度快(响应时间90ms),重复性能优异(循环次数20000)。同时,由于兼具裂纹和褶皱的特殊微观结构,该应变传感器能有效克服高分子复合材料的应变响应性能的滞后效应,表现出良好的力敏响应稳定性。研究了材料在可穿戴电子方面应用,发现该传感器能够监测多种人体运动所造成的宽幅的应变变化,如关节弯曲、脉搏跳动、声带振动等等。这说明该传感器在人体健康监测、电子皮肤和人体运动检测领域具有广泛的应用前景。另一方面,我们分别将HDPE粉末、UHMWPE粉末和导电填料碳纳米管CNTs在乙醇溶剂的辅助下进行分散,后热压成型制备复合材料。并通过此过程使CNTs选择性分布在HDPE和UHMWPE基体的界面,得到了具有隔离结构的CNTs/HDPE/UHMWPE和CPCs。该制备方法综合考虑了高分子形态控制和导电填料分布控制,显著降低了CPCs的逾渗值(0.3wt.%)。导电填料的增加有效地提升了复合材料的电学和力学性能。详细研究了隔离结构导电网络及其演化对CNTs/HDPE/UHMWPE复合材料应变-电阻行为的影响。在进行循环拉伸测试时,随着循环次数增加,材料残余应变逐渐增加,而由于CNTs的一维特性影响,在拉伸的过程中一些CNTs沿拉伸方向重新取向,加之复合材料的粘弹性行为造成的滞后效应的影响,CNTs在沿拉力方向上重新形成了更加完善的导电网络,复合材料的响应度峰值逐渐降低。通过对CPCs力电性能的研究,总结出CPCs在应力场作用下导电填料含量、拉伸速度等与材料应力响应行为之间的一系列关系。
[Abstract]:The conductive polymer composite (Conductive polymer composites, CPCs) is prepared by the composite of conductive fillers filled with polymer matrix, and.CPCs is widely used in the self-control temperature heating materials, sensors, electromagnetic shielding and antistatic materials, which have aroused the researchers' extensive attention to.CPCs in the external field of stress, temperature, gas, liquid and so on. It shows a rich response behavior. Among them, due to the sensitive response behavior of CPCs in the tensile stress field, it is becoming more and more widely concerned in the field of motion detection device, wearable strain sensor, flexible electronic skin, etc. Although the CPCs based stress sensitive material has very excellent characteristics (such as easy processing, low cost), However, there are still many shortcomings that need to be solved, such as the lag effect and the poor repeatability of CPCs in the cyclic stress field, which greatly restricts the application space of CPCs. Therefore, it is very important to construct a new structure of polymer materials to regulate the performance of CPCs. In the field of flexible strain sensor, the response of CPCs The performance, such as sensitivity and repeatability, is very important. The study shows that the crack strain sensor has high response performance, but the response range is limited; the response stability of the folded strain sensing material is excellent, but the sensitivity is not high. This paper designs a micro structure with a crack folds which is based on the special crack folds. Structure, the GNPs/TPU/PDMS flexible force sensitive composite is prepared. This new type of crack fold structure is produced by pressure drag on the material. The fold structure is distributed evenly in the GNPs layer, the crack is distributed in the fold structure and the direction of the fold structure is the same. The electrical properties of the strain sensor under the tensile action are studied. It is found that the GF of the sensor can reach 150 and keep stable in a larger strain range (0%~20%). Through the analysis of the morphology of the material, the change of the crack is observed when the composite is stretched, and the effect of the crack opening and closing on the response performance of the composite is discussed based on the crack propagation and recovery mechanism. Small strain (strain 0.1%), and rapid response (response time 90ms), excellent repeatability (20000). At the same time, because of the special microstructure of cracks and folds, the strain sensor can effectively overcome the lag effect of strain response of polymer composites and show good stability of the response to force sensitivity. In wearable electronics, it is found that the sensor can monitor the wide strain changes caused by a variety of human motion, such as joint bending, pulse beating, sound band vibration and so on. This shows that the sensor has wide application prospects in human health monitoring, electronic skin and human motion detection domain. On the other hand, we respectively The HDPE powder, the UHMWPE powder and the conductive filler carbon nanotube CNTs were dispersed with the aid of ethanol solvent, and then the composites were prepared by hot pressing. By this process, the CNTs was selectively distributed on the interface of HDPE and UHMWPE matrix, and the isolation structure of CNTs/HDPE/UHMWPE and CPCs. was obtained, and the polymer form was taken into consideration. State control and conductive filler distribution control significantly reduce the percolation value of CPCs (0.3wt.%). The increase of conductive filler increases the electrical and mechanical properties of the composite effectively. The effect of the conductive network on the isolation structure and its evolution on the strain resistance behavior of the CNTs/HDPE/UHMWPE composite is studied in detail. As the number of cycles increases, the residual strain of the material increases gradually, and because of the one-dimensional characteristics of CNTs, some CNTs reorientation along the tensile direction during the stretching process, and the effect of the hysteresis effect caused by the viscoelastic behavior of the composite, CNTs has reformed a more perfect conductive network along the direction of the tensile force, and the composite material is reformed. The peak of the response degree is gradually reduced. Through the study of the electrical and electrical properties of CPCs, a series of relationships between the content of the conductive filler and the tensile velocity and the stress response behavior of the material under the action of the stress field are summarized.
【学位授予单位】:郑州大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:TB332
【参考文献】
相关期刊论文 前1条
1 赵俊慧;代坤;郑国强;张荣正;陈静波;刘春太;申长雨;;CPCs在应力场下的性能演变及机理研究进展[J];合成树脂及塑料;2012年03期
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