自修复聚合物复合材料的设计、制备及应用研究

发布时间：2018-12-08 07:50

【摘要】：聚合物及复合材料以其优异的性能得到广泛应用。但在加工和使用过程中,不可避免地会产生微裂纹等损伤,从而导致材料的综合性能下降并产生隐患。在此背景下,聚合物及复合材料自修复性能的研究应运而生。基于Diels-Alder(DA)化学的自修复材料具有制备灵活、反应条件温和、可多次修复等特点而得到广泛研究。但是,当前基于DA化学的自修复研究工作集中于聚合物基自修复材料及其基本物性研究,而聚合物材料自身功能有限,大大限制其实际应用。同时,针对DA体系的修复方式往往局限于加热,修复时间长、效率较低。因此,开展基于DA化学的聚合物基复合材料的制备、应用及新型修复方式的研究意义重大。石墨烯是一种新型二维材料,具有极大的比表面积、优异的机械性能,同时也是电和热的优良导体,构建石墨烯/自修复聚合物复合材料具有重要的研究价值。本文通过引入石墨烯纳米片及三维石墨烯,研究自修复复合材料的综合性能及其在可修复柔性电子材料领域中的应用。同时,利用石墨烯对微波的吸收-转热作用,拓展新的高效修复方式。主要研究工作如下:1.基于DA化学的自修复酚醛环氧树脂的制备及性能研究。利用商用的酚醛环氧树脂,通过简单的化学改性在环氧体系中引入呋喃基团,然后以双马来酰亚胺交联得到具有优异综合性能和可修复性能的环氧树脂。该材料不仅具有类似传统环氧树脂的优异的力学性能和耐热性能,同时具有优异的热可逆性质,具体表现为可逆的溶胶-凝胶、热可修复及热可溶解等特点。该材料可应用于自修复电子封装材料等领域。2.原位聚合制备氧化石墨烯/聚氨酯自修复复合材料及性能研究。以原位聚合逐步反应制备氧化石墨烯/聚氨酯复合材料,同时引入呋喃-马来酰亚胺体系作为自修复的单元。在较低添加量时,氧化石墨烯可以均匀分散在复合材料中,并显著提高所制备材料的杨氏模量、断裂强度及断裂伸长率等性能;此外,由于大量存在由DA化学构成的可逆六元环使得所制备的复合材料具有优异的可修复能力,并通过原子力显微镜及应力-应变测试进行表征。3.石墨烯海绵的设计、制备及其在传感器上的应用。由于强烈的π-π相互作用,石墨烯纳米材料在与聚合物复合的过程中,极易产生团聚。本章设计制备三维石墨烯海绵作为新型纳米填料并验证其在柔性传感器上的应用。首先,使用新型还原剂硫化铵,通过还原自组装得到石墨烯水凝胶。然后,经过增强、冷冻干燥等工艺制备出可压缩-回弹的三维石墨烯,并将其应用于电阻式压力传感器。另一方面,利用三维石墨烯中丰富的孔洞结构,在其内部原位聚合聚二甲基硅氧烷制备出柔性拉伸传感器。所制备的柔性应变传感器具有优异的拉伸性能、高灵敏度、良好的稳定性,并可对人体运动信号进行检测,表现出了优异的稳定性和灵敏性。4.共价键连接石墨烯/聚氨酯复合材料及其在可修复柔性电子中的应用。为提高自修复材料的修复效率,本章利用石墨烯显著的微波吸收-转热效应,制备基于DA化学的石墨烯复合材料。通过呋喃甲胺对氧化石墨烯进行功能化并还原制备出还原功能化氧化石墨烯(RFGO),并利用呋喃与马来酰亚胺的共价键结合将RFGO引入复合材料体系中。RFGO具有优异的分散性及高效的微波吸收-转热能力,不仅显著的提高了复合材料的机械性能和热稳定性,也使其具有优异的微波修复能力。此外,将三维石墨烯海绵破碎制备成三维导电网络与之复合制备出可修复的柔性电子材料,并成功应用于柔性导体及检测手指弯曲等信号的应变传感器。最后,所制备的柔性电子材料在完全切断后可通过微波作用5分钟完成修复,具有在可修复柔性电子材料中的应用潜力。5.三维石墨烯基自修复柔性电子材料的制备及应用。为增强三维石墨烯与基于DA化学的自修复聚合物的结合能力,本章以呋喃甲胺作为还原剂和功能化分子制备三维石墨烯海绵。通过控制三维石墨烯海绵内部结构,并采用灌注-原位凝胶-干燥等方式制备出具有优异拉伸性能、热稳定性、低温DA逆反应响应的三维石墨烯基自修复复合材料。所制备的材料可以直接应用于人体运动检测的柔性应变传感器,并可通过加热、微波等多种方式进行修复,有望应用于可修复柔性电子中。
[Abstract]:The polymer and the composite material are widely used in the performance of the polymer and the composite material. but in the process of processing and using, the damage of micro-cracks and the like is inevitably generated, so that the comprehensive performance of the material can be reduced and a hidden danger is generated. In this background, the self-healing properties of the polymer and the composites have come into being. The self-repairing material based on Diels-Alder (DA) chemistry has the characteristics of flexible preparation, mild reaction condition and multiple repair. However, the self-repair work based on DA chemistry is focused on the polymer-based self-repairing material and its basic physical properties, and the self-function of the polymer material is limited, and its practical application is greatly limited. At the same time, the repair method for the DA system is often limited to the heating, the repair time is long, and the efficiency is low. Therefore, the preparation, application and new repair methods of the polymer-based composite based on DA chemistry are of great significance. Graphene is a novel two-dimensional material, which has a great specific surface area, excellent mechanical properties, and is also an excellent conductor of electricity and heat, and the construction of the graphene/ self-repairing polymer composite material has important research value. In this paper, the comprehensive performance of self-repairing composite and its application in the field of repairing flexible electronic material are studied by introducing the graphene nanosheet and the three-dimensional graphene. meanwhile, the absorption of the microwave by the graphene is utilized, and the novel high-efficiency repair mode is expanded. The main research work is as follows: 1. Preparation and performance of self-repairing phenolic epoxy resin based on DA chemistry. By means of a commercial phenolic epoxy resin, an epoxy group is introduced in an epoxy system by a simple chemical modification, and then an epoxy resin with excellent comprehensive performance and excellent properties can be obtained by crosslinking with a double-maleimide. The material not only has excellent mechanical property and heat resistance similar to that of the traditional epoxy resin, but also has excellent heat reversible property, and the material has the characteristics of reversible sol-gel, heat-curable and heat-soluble, and the like. the material can be applied to the fields of self-repairing electronic packaging materials and the like. Self-repair of graphene/ polyurethane self-repairing composite and its properties by in-situ polymerization. The graphene/ polyurethane composite material is prepared by the in-situ polymerization step-by-step reaction, and simultaneously the polyoxyalkylene-maleimide system is introduced as a self-repairing unit. in that low adde amount, the graphene oxide can be uniformly dispersed in the composite material, and the properties of the Young's modulus, the breaking strength and the elongation at break of the prepared material can be obviously improved; in addition, Due to the large number of reversible six-membered rings made of DA chemistry, the prepared composite material has excellent fixability and is characterized by an atomic force microscope and a stress-strain test. The design, preparation and application of graphene sponge. The graphene nano material is very easy to be agglomerated in the process of compounding with the polymer due to the strong oxygen-to-sulfur interaction. This chapter is designed to prepare three-dimensional graphene sponge as a new type of nano-filler and to verify its application on the flexible sensor. First, a new type of reducing agent is used to cure the sulfur, and the graphene hydrogel is obtained by reduction and self-assembly. then, the compressible-rebound three-dimensional graphene is prepared through the processes of reinforcement, freeze drying and the like, and is applied to a resistance type pressure sensor. on the other hand, the flexible tensile sensor is prepared by in-situ polymerization of the polydimethylsiloxanes in the internal in-situ polymerization of the polydimethylsiloxanes with a rich pore structure in the three-dimensional graphene. The prepared flexible strain sensor has excellent tensile property, high sensitivity, good stability, and can be used for detecting human body motion signals, and has excellent stability and sensitivity. The invention relates to a graphene/ polyurethane composite material which is covalently bonded and an application of the graphene/ polyurethane composite material in the repair of flexible electrons. In order to improve the repair efficiency of the self-repairing material, the graphene composite material based on DA chemistry is prepared by utilizing the remarkable microwave absorption-rotating effect of the graphene. the oxidized graphene is functionalized and reduced to prepare the reduced functionalized graphene oxide (RFGO) through the preparation of methylamine, and the RFGO is introduced into the composite material system by using the covalent bond of the disulfide bond and the maleimide. The RGO has excellent dispersibility and high efficient microwave absorption-rotating heat capacity, and not only obviously improves the mechanical property and the thermal stability of the composite material, but also has excellent microwave recovery capability. In addition, the three-dimensional graphene sponge is broken and prepared into a three-dimensional conductive network and a composite preparation of the flexible electronic material, and the flexible electronic material can be successfully applied to the strain sensor of the flexible conductor and the detection finger bending and the like. Finally, the prepared flexible electronic material can be repaired by microwave for 5 minutes after being completely cut, and has the potential of application in the repair of flexible electronic materials. Preparation and application of three-dimensional graphene-based self-repairing flexible electronic material. In order to enhance the binding ability of the three-dimensional graphene and the self-repairing polymer based on DA chemistry, the three-dimensional graphene sponge is prepared by using methylamine as a reducing agent and a functional molecule. The three-dimensional graphene-based self-repairing composite material with excellent tensile property, thermal stability and low-temperature DA reverse response response is prepared by controlling the internal structure of the three-dimensional graphene sponge, and adopting a perfusion-in-situ gel-drying method and the like. The prepared material can be directly applied to a flexible strain sensor for human motion detection, and can be repaired by a plurality of methods such as heating, microwave and the like, and is expected to be applied to the repair of flexible electrons.
【学位授予单位】：中国科学院大学(中国科学院深圳先进技术研究院)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB33

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