Morphology and crystallization behavior of HDPE/CNT nanocomposite

Abstract

Polymer carbon nanotube nanocomposites (PCNs) represent the first realized major commercial application of carbon nanotubes (CNTs). In this study, high density polyethylene (HDPE)/CNT PCNs have been prepared using a solution blending technique. Both pristine single-walled nanotubes (SWNT) and polyethylene (PE) single crystal decorated CNTs (so called nano hybrid shish kebabs, NHSKs) have been used as the precursors for PCN preparation. Polarized light microscopy, transmission electron microscopy, scanning electron microscopy, differential scanning calorimetry, and thermogravimetry were used to study the morphology, crystallization behavior, and thermal stability of the resulting PCNs. The PCNs from pristine SWNTs possess a more dense morphology than do the PCNs prepared from NHSKs; PE single crystal lamellae are perpendicular or oblique to the CNT axis, leading to relatively "open-structured PCNs. Heterogeneous nucleation occurred in both nonisothermal and isothermal crystallization of PCNs and the crystallization kinetics are much faster than that of the pure HDPE. Thermal stability of PCNs showed dramatic enhancement (as high as 70°C/115°C improvement of T max in N 2 /air atmosphere, respectively), which is attributed to the formation of the free radical scavenging CNT network.