Effect of microstructure and morphological properties of carbon nanotubes on the length reduction during melt processing

Length of multi-walled carbon nanotube (MWCNT) has strong impact on mechanical strength of MWCNT/polymer composite. In this paper, MWCNT/polyamide 6, 6 (PA 66) composites using ten different MWCNTs were prepared by melt processing. The harsh mixing process used to achieve a fine dispersion of MWCNTs in the polymer matrix broke and severely reduced the lengths of the MWCNTs. The characteristics of MWCNTs that influence the breakage and length reduction were systematically and experimentally explored. Insights into designing the microstructures and morphological properties of pristine MWCNTs were provided, based on the correlation data and statistical evaluation results, in an effort to preserve the high aspect ratio of the MWCNTs during the melt mixing process, thereby expecting the enhanced mechanical properties of the composite.