Dispersion of multi-walled and double-walled carbon nanotubes in polylactide and polyamide 11
Mousavi Zeinab (1)*, Carreau Pierre J. (1), Heuzey Marie-Claude (1), Kamal Musa R. (2), Flahaut Emmanuel (3)
(1) Department of Chemical Engineering, Polytechnique Montreal - QC - Canada, (2) Department of Chemical Engineering, McGill University - QC - Canada, (3) Université Paul Sabatier - Toulouse - France
The dispersion of multi-walled carbon nanotubes (MWCNTs) and double-walled carbon nanotubes (DWCNTs) in a polylactide (PLA) and a polyamide 11 (PA11) was evaluated and compared through rheological characterization. The diameter of MWCNTs is between 10 and 20 nm and that of the DWCNTs is between 1 and 3 nm. Nanocomposites were prepared using an internal mixer at 200 °C. Adding 1 wt% of MWCNTs to PLA resulted in a considerable increase of the complex viscosity (1800%, at ω= 0.18 rad/s and 200 °C). 1 wt% of DWCNTs increased the complex viscosity by 90% while resulting in PLA degradation. Also, the slope of the storage modulus at low frequencies was reduced from 1.7 to 0.25 for both types of nanoparticles, confirming the formation of carbon nanotube networks in PLA at 1 wt% for both types of nanoparticles. In PA11, the DWCNTs showed better enhancement of the rheological properties compared to the MWCNTs at 1 wt% (190% vs. 30%, respectively) and 2 wt% (1900% vs 190%, respectively). The rheological data were analyzed in light of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Finally, the electrical resistivity and the dynamic mechanical thermal analysis (DMTA) data obtained for both nanocomposites were compared and correlated with the rheological properties.