Tough and flexible styrene-butadiene block copolymers with defined carbon-based nanofillers for electrical and sensing applications

具有特定碳基纳米填料的坚韧而柔韧的苯乙烯-丁二烯嵌段共聚物，适用于电气和传感应用

• 批准号: 268676966
• 负责人: Dr.-Ing. Ulrike Staudinger
• 金额: --
• 依托单位: Institut Makromolekulare Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/268676966?language=en
• 关键词: Tough; flexible; styrene; butadiene; block

The aim of the project is the development of functional nanocomposites based on tough and flexible styrene-butadiene block copolymers (BCPs) with carbon nanotubes (CNTs) suitable for electrical and sensing applications. The nanostructured BCP/CNT composites with modified nanofillers, which were comprehensively investigated in the first project, are used as a basis for this study. They exhibit a high electrical conductivity already at low CNT contents of ~ 1 Ma% while retaining the nanostructure and the extraordinary mechanical property profile of the BCPs. To achieve an optimal dispersion and localization of the CNTs in the nm-scaled BCP phases and thus to further increase the electrical conductivity at low CNT contents, strongly shortened CNTs are used. Different size fractions from 500 nm to 80 nm are realized by shortening in a ball mill or by a special laser treatment with a microfluidic vortex flow device. A modification of the CNTs with PS groups should increase the interaction between filler and PS phase in the BCP and support the dispersion and selective arrangement of the CNTs in the PS phase or at the interface of both phases. The BCP composites are prepared by solution mixing and melt mixing and the morphologies are defined and reproducibly adjusted by subsequent tempering. The influence of the size fractions used (critical CNT lengths) and the chemical functionalization of the CNTs on the morphology and the electrical and mechanical properties are analyzed. In addition, fracture mechanical investigations are carried out on notched test specimens of selected materials with evaluation of the crack toughness by using the Essential Work-of-Fracture concept, which is suitable for highly ductile polymer materials.The characterization of the piezoresistive behavior of electrically conductive BCP/CNT composites is carried out by measuring the deformation-induced resistance change during the uniaxial tensile test and in cyclic hysteresis tests in the viscoelastic range of the composites. For the application as deformation sensors, the adjustment of a high piezoresistive sensitivity (high gauge factor) and a high linearity of the deformation-dependent resistance change within a wide deformation range as well as a good repeatability of the measurement with cyclic sensing are decisive. These properties are governed by the ductility of the matrix polymer and the density and regularity of the CNT network. The aim is to understand the influence of the CNT concentration and the CNT modification on the properties of the filler network in the BCP and its effects on the piezoresistive behavior of the composites in order to be able to adjust the properties of the composites for applications in the field of deformation sensing.

该项目的目的是开发基于坚韧和柔性苯乙烯-丁二烯嵌段共聚物（BCP）与碳纳米管（CNT）的功能性纳米复合材料，适用于电气和传感应用。在第一个项目中进行了全面研究的具有改性纳米填料的纳米结构BCP/CNT复合材料被用作本研究的基础。它们在~ 1 Ma%的低CNT含量下已经表现出高电导率，同时保留BCP的纳米结构和非凡的机械性能。为了实现CNT在纳米级BCP相中的最佳分散和定位，从而进一步提高低CNT含量下的电导率，使用强烈缩短的CNT。从500 nm到80 nm的不同粒度级通过在球磨机中缩短或通过使用微流体涡流装置的特殊激光处理来实现。用PS基团对CNT进行改性应增加BCP中填料和PS相之间的相互作用，并支持CNT在PS相中或两相界面处的分散和选择性排列。通过溶液混合和熔融混合制备BCP复合材料，并通过随后的回火来定义和可重复地调整形态。所使用的尺寸分数（临界CNT长度）和化学官能化的碳纳米管的形态和电气和机械性能的影响进行了分析。此外，断裂力学研究进行了缺口试样的选定材料的裂纹韧性的评价，通过使用基本断裂功的概念，该方法适用于高韧性聚合物材料。通过测量BCP/CNT复合材料的变形量来表征其压阻行为。在复合材料的粘弹性范围内，在单轴拉伸试验和循环滞后试验期间引起的电阻变化。对于作为变形传感器的应用，在宽的变形范围内调节高的压阻灵敏度（高的应变系数）和与变形相关的电阻变化的高线性度以及在循环感测的情况下测量的良好重复性是决定性的。这些性质由基质聚合物的延展性和CNT网络的密度和规则性决定。目的是了解CNT浓度和CNT改性对BCP中的填料网络的性质的影响及其对复合材料的压阻行为的影响，以便能够调整复合材料的性质以用于变形传感领域中的应用。