Interfaces between the nanocarbon reinforcements and a resin matrix are critical for producing high performance nanocomposites. Functionalization of carbonaceous materials has been proven effective for improving the mechanical properties of nanocomposites to achieve better load transfer. To understand the interface between carbon reinforcement materials and resin matrix, composite samples were cut with an ultra-microtome or a thin lamellae sample was prepared using focused ion beam (FIB). We investigated the interface using high-resolution transmission electron microscopy (HR-TEM) and its chemical functionalization effects via scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy spectrum imaging (EELS) techniques. Using HRTEM, we studied the interaction and formation of interface zones between CNTs with different resin matrices. Nanocomposite cross-section images revealed CNT and CNT bundle structures could be clearly identified and measured. The interactions of CNT surfaces with intimate resin to form clear templated interface zones. Also, the effects of functionalization was studied based on the C-K edge EELS. The results show that state of the sp2 bonding and its distributions at the CNT/resin interface can be clearly visualized through the EELS mapping. We found that the functionalized CNT/polymer samples exhibited a lower fraction of sp2 bonding and a lower π*/σ* ratio compared to the non-functionalized cases. A good correlation between near edge fine structures and low-loss plasmon energies was also observed. Those atomic resolution results are important toward providing quantitative representation of nanocomposite interface to support material development and validation of modeling effort.

Interface zone and functionalization effect study of CNT/polymeric nanocomposites via Transmission Electron Microscopy (TEM) and Electron Energy Loss Spectroscopy (EELS)

2019 Spring National Meeting

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