科研之友
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摘要
A model for the strength of pure carbon nanotube (CNT) fibers Is derived and parametrized using experimental:data-and computational simulations. The model points to the parameters of the subunits that must be optimized in order to produce improvements In the strength of the macroscopic CNT fiber primarily nanotube length and shear strength between CNTs. Fractography analysis of-the CNT-fibers reveals a fibrous fracture surface and indicates that fiber strength originates from resistance to nanotube pull-out and is thus Proportional the nanotube nanotube interface contract area and shear strength. The contact area between adjacent nanotubes is determined by their degree of polygonization or collapse, which in turn depends on their diameter and number of-layers. We show that larger diameter tubes with fewer walls have a greater degree of contact, as determined by continuum elasticity theory, Molecular mechanics, and image analysis transmission election micrographs. According to our model, the axial stress in the CNTs is built up by stress transfer between adjacent CNTs through shear and is thus proportional to CNT length, as supported by data in the literature for CNT fibers produced by different methods and research groups. Our CNT fliers have a yarn-like structure in that rather than being solid, they are made of a network of filament subunits; Indeed, the Model is consistent with those developed for conventional yarn-like fibers.
- 出版日期2011-3
