I, Srikanth and Ch, Subrahmanyam
(2014)
Effect of Carbon nanotubes/nanofibers Reinforcement on Mechanical and Thermal Properties of CFRPs.
PhD thesis, Indian Institute of Technology Hyderabad.
Abstract
Multiwalled carbon nanotubes (MWCNTs) were purified to ultra high purity levels (99.9%) by high temperature (26000C) heat treatment method. It was observed that, the structural perfection of MWCNTs increased besides improvement in their purity. Based on the TGA, XRD, TEM and Raman spectroscopy studies mechanisms are proposed for the observed structural changes to MWCNTs. These mechanisms says that, during high temperature treatment, the innermost walls of the MWCNTs collapse due to thermal stresses. However, it was observed that, as long as some traces of the metallic impurities are present, they suppress the collapse of the internal walls. Once the metallic impurities are removed, structural distortion of MWCNTs takes place. It was observed that heat treatment for 60 mins is optimum to obtain highly pure and structurally perfect MWCNTs. These purified MWCNTs were subsequently amino functionalised. FT-IR and XPS methods were used to ascertain the functional groups present on the MWCNTs.
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