Structure-property relations of nanostructured carbon systems as a function of processing

[摘要] Due to their intrinsic properties and nanometer scale, carbon nanotubes (CNTs) are commonly used to enhance the material properties of engineering materials. However, structural defects can significantly alter the intrinsic properties of CNTs, thereby limiting the physical properties of aligned CNT nanocomposite architectures. Previous studies have shown the difficulty in getting quantitative data for CNT quality once embedded within a carbon matrix. Therefore, studies that focused on the CNTs and carbon matrix separately were necessary. A study on the CNTs and carbon matrix response to pyrolyzation temperatures has recently been completed and is used to inform and motivate the research reported here. This research will focus primarily on the effects of different temperature ramping rates (TRR;;s) during pyrolysis of phenolic resin to form the ceramic matrix. Preliminary X-Ray Diffraction (XRD), Raman spectroscopy and Vickers Hardness results indicate that increasing the temperature ramping rate (in the range of 10°C/min - 40°C/min) increases the prevalence of defects in the nanocomposite system as well as increasing the standard error of both crystallite sizes and hardness, while maintaining the mean of the distribution. Future studies exploring aligned CNT carbon matrix nanocomposites (A-CMNCs) and more extreme temperature ramping rates are proposed.

[发布机构] Massachusetts Institute of Technology