功能化石墨烯增强聚酰亚胺纳米复合材料的制备及性能研究

发布时间：2018-04-20 22:29

本文选题：聚酰亚胺 + 功能化氧化石墨烯　；参考：《东华理工大学》2016年硕士论文

【摘要】：聚酰亚胺(PI)材料由于具有突出的耐高温性、高绝缘性和优异的力学性能等综合性能,在耐高温塑料、集成电路、气体分离膜、航空等领域有着广泛的用途。但是纯聚酰亚胺材料的单一性能已不能满足人们对材料的要求。通过在聚酰亚胺基体中加入改性填料,使之有效纳米复合,可提高复合材料的热性能、机械性能和导电性能。石墨烯是常用的纳米增强填料之一,但由于它强的层间作用力使其容易在基体中产生堆积。氧化石墨烯(GO)表面共价键连接着大量含氧基团,为GO的表面功能化提供了大量的反应位点。因此,可以通过共价键功能化对其进行表面改性,从而使GO与基体材料之间产生良好的相容性。GO与聚合物基体之间的均匀分散及强的界面相互作用力是获得高性能聚酰亚胺材料的关键。本论文通过原位聚合和热亚胺化,制备出一系列功能化石墨烯/聚酰亚胺复合材料,并对填料的形貌与结构,聚酰亚胺材料的性能进行了表征,本文主要开展了三个方面的工作:(1)首先利用环己基异氰酸酯(CI)对GO进行改性,得到功能化氧化石墨烯(FGO)纳米片,该纳米材料在基体中表现出良好的分散效果。FGO的加入显著影响了PI复合材料的宏观性能。加入2.0 wt%的FGO填料,复合材料的拉伸强度和拉伸模量分别增加了56.5%和43.8%。此外,由于FGO的加入,PI纳米复合材料的热稳定性和疏水性有了显著的提高。(2)通过在基体中掺杂十八烷基胺(ODA)功能化的氧化石墨烯(ODA-f GO)纳米片状材料来制备一系列聚酰亚胺复合材料(PI/ODA-f GO)。由于ODA-f GO纳米片的均匀分散以及与聚酰亚胺基体间强的相互作用,所制备的PI/ODA-f GO的机械性能、导电性能和热传导性能得到了显著提高。与纯聚酰亚胺相比,掺杂3 wt%的ODA-f GO的复合材料的拉伸强度增加了30.58 MPa,拉伸模量提高了1.54 GPa,导电率和热传导系数分别提高了1011倍和3倍。(3)采用对苯二胺对GO表面进行共价键功能化,得到氨基功能化氧化石墨烯(GO-NH_2),GO表面性质的改变使其在基体中能够均匀分散。改性后的GO-NH_2中的氨基与PAA基体之间通过共价键结合产生强的界面相互作用,显著增强了复合材料(PI/GO-NH_2)的机械性能、耐热性能和疏水性能。PI/3%GO-NH_2纳米复合材料的拉伸模量和拉伸强度比PI分别提高了63%和54.5%,接触角增大了20°,耐热性能也明显增强。而且,PI/3%GO-NH_2复合材料比PI/3%GO表现出更好的综合性质。
[Abstract]:Polyimide (Pi) materials have been widely used in high temperature resistant plastics, integrated circuits, gas separation membranes, aviation and other fields because of their outstanding high temperature resistance, high insulation and excellent mechanical properties. However, the single properties of pure polyimide materials can not meet the requirements of materials. The thermal, mechanical and conductive properties of the composites can be improved by adding the modified fillers to the polyimide matrix and making them effectively nanocomposite. Graphene is one of the commonly used nano-reinforced fillers, but it is easy to pile up in the matrix because of its strong interlaminar force. The surface covalent bond of graphene oxide (GOO) is connected with a large number of oxygen-containing groups, which provides a large number of reaction sites for the surface functionalization of go. Therefore, the surface can be modified by covalent bond functionalization. Thus, it is the key to obtain high performance polyimide material that good compatibility between go and matrix can be produced. The uniform dispersion between go and polymer matrix and the strong interfacial interaction force are the key to obtain high performance polyimide material. In this paper, a series of functionalized graphene / polyimide composites were prepared by in-situ polymerization and thermal imidization. The morphology and structure of the filler and the properties of the polyimide were characterized. Firstly, go was modified by cyclohexyl isocyanate (CII) to obtain functionalized graphene oxide FGONs. The nano-materials showed good dispersion effect in the matrix. The addition of FGO significantly affected the macroscopic properties of Pi composites. The tensile strength and tensile modulus of the composites increased by 56.5% and 43.8% respectively by adding 2.0 wt% FGO filler. In addition, Because the thermal stability and hydrophobicity of FGO / Pi nanocomposites have been greatly improved, a series of polyimide composites (PI- / ODA-f) have been prepared by doping the functional graphene oxide (ODA-f GOA) nanoparticles into the matrix. Due to the homogeneous dispersion of ODA-f go nanoparticles and the strong interaction with polyimide matrix, the mechanical properties, conductivity and thermal conductivity of the prepared PI/ODA-f go films were improved significantly. Compared with pure polyimide, The tensile strength of the composites doped with 3 wt% ODA-f go was increased by 30.58 MPA, the tensile modulus was increased by 1.54 GPA, and the conductivity and thermal conductivity of the composites were increased by 1011 and 3 times, respectively. Amino-functionalized graphene oxide (GO-NH _ 2O _ 2) was obtained by changing the surface properties of GO-NH _ 2H _ 2O _ 3 so that it could be dispersed uniformly in the matrix. The strong interfacial interaction between the amino groups in the modified GO-NH_2 and the PAA matrix is produced by covalent bonding, which significantly enhances the mechanical properties of the composite PI- / GO-NH2. The tensile modulus and tensile strength of GO-NH2 nanocomposites were increased by 63% and 54.5%, respectively, and the contact angle was increased by 20 掳. Moreover, PI- / 3- GO-NH2 composite shows better comprehensive properties than PI/3%GO.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB332

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