(A) study on polymer/multi-walled carbon nanotube nanocomposites

Abstract

In this study, industrial grade multiwalled carbon nanotubes (MWNTs, Nanocyl 7000) were incorporated in various polymers, such as polyamide 6 (PA6), polyamide 11 (PA11), polyamide 12 (PA12), high-density polyethylene (HDPE), polypropylene (PP), and polycarbonate (PC), by simple melt mixing process. The main interest of this research is to investigate the effect of molecular weight of the polymer matrix and the effect of interaction between MWNTs and polymers on the dispersion of the MWNTs and various physical properties, such as electrical, rheological, thermal, and mechanical properties, etc. Another focus is to come up with a universal empirical equation which can simply, but also accurately explain the electrical property of various polymer/MWNT nanocomposites. In Chapter 2, the effect of molecular weight of the polymer matrix on the dispersion of MWNTs has been investigated for HDPE/MWNT and PC/MWNT nanocomposite materials. The dispersion of MWNTs in the polymer matrix showed strong correlations with the melt viscosity of the polymer matrix, in other words, the molecular weight of the polymer material. In order to investigate the effect on the dispersion of the MWNTs and various physical properties of the composites, several experimental methods, such as 4-point probe, SEM and ARES, have been employed. From the results it is interpretable that, using high melt viscosity polymer as the matrix material restricted the mobility of the MWNTs, and also hindered the dispersion of MWNTs due to the high entanglement density of the polymer matrix. In Chapter 3, the effect of interaction, especially the van der Waals force interaction, between the MWNT and the polymer material has been investigated using three different kinds of polyamides (PAs): PA6, PA11 and PA12. By comparing the dispersion of MWNTs in PAs and various physical properties measured by using 4-pin probe, SEM, ARES, DSC, TGA, DMTA and XRD, it can be concluded that interaction between MWNTs and PAs ...