| Carbon nanomaterials, including carbon nanotube and graphene, are intriguing materials originating from their chemical structures and strong all carbon lattices. They have been used for preparing composite materials as fillers to improve their chemical and physical properties. To achieve outstanding performance, the carbon nanomaterials are required to be well dispersed/distributed in the matrix/space and keep the filling content as high as possible. How to optimize the distribution of carbon nanomaterials and adjust the interface characteristics are the most compelling problems yet to be solved. Here, the carbon nanotubes (CNT)/Epoxy composites, CNT/Polyaniline composites, Unzipped CNT aerogel and graphene/Epoxy coating were chosen as the study of interest to explore the impact of the interfacial properties and the distribution of carbon nanomaterials on the performance of composites.The first part of the thesis investigates properties of the interface between carbon nanotubes and epoxy based shape memory polymers through adjusting the temperatures at which the composites are deformed. Epoxy shape memory polymer (SMP) reinforced by CNT with weight percents of0.83wt.%and1.42wt.%were fabricated by high-shear mixing method. The CNT reinforcement efficiency is found to be dependent on temperature, and there is an optimal temperature for achieving the maximum CNT reinforcement efficiency. The addition of CNT does not change the shape fixing ratio and shape recovery ratio of SMP, while the shape recovery stress and shape recovery rate are enhanced. A shear lag model is developed to explain the optimal temperature for highest carbon nanotube reinforcement efficiency.In order to enhance the electrical properties and cycling stability of polyaniline, CNT sponges (CNTS)/polyaniline composites were fabricated for the application of supercapacitors in the second part of the thesis. The supercapacitor has excellent capacitance per unit area of1.89F/cm2at4.9A/cm2, and the capacitance almost does not change after3000charge-discharge cycles. It is revealed that the highly structural integrity and interconnected pores distribution are the reasons for the outstanding electrochemical performance of the supercapacitor. On the basis of the above experimental results and also inspired by the structures of leaf (which is constituted by vein, midrib and lamina), CNTs were partially unzipped along their axial direction by using Tour’s method and the unzipped degree of CNT is controlled by the amount of KMnO4. The unzipped CNTs were further assembled to aerogels by three methods, namely, direct freeze-drying (DFD), self-assembly followed by freeze-drying(SAFD), hydrothermal followed by freeze-drying(HTFD). It is concluded that both the porous structures and mechanical properties are highly dependent on the unzipped degree of CNT and concentration of unzipped CNT in the precursor solution. The aerogels from SAFA and HTFD are fragile, while the ones from DFD have highly reversible compressibility and exhibited reasonable capacitance of58F/g which is much higher than CNTS (~25F/g) with a similar porous structure. The aerogel from DFD has extremely stable piezoresistive properties with the sensitivity only increasing less than5%after5000compressive cycles.Owing to the2-Dimension characteristic of graphene oxide (GO) and its super dispersiblity in water, I present the studies about anti-corrosion and mechanical properties graphene oxide reinforced water-borne epoxy in the last part of the thesis. For the mechanical properties, I take advantage of nano-indentation to measure the modulus and hardness of the composites, which are enhanced by18%and9.8%at0.07wt.%of GO,54%and14%at0.2wt.%of GO, respectively. For the anti-corrosion properties, electrochemical method was utilized to characterize the corrosion rate, which decreased by a factor of4at0.07wt.%of GO. |
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