Thermal, Electrical and Mechanical Properties of Blended and Solvent Cast PLA-MWNT Composites

Abstract

This paper compares melt blending and solvent casting as processing routes for fabricating Polylactide (PLA)-Multiwall carbon nanotube (MWNT) composites. Composites with an MWNT content of 0, 0.5, 2 and 5 wt.% MWNT were fabricated using both processing techniques and their thermal, electrical and mechanical properties were evaluated. Two types of solvents, chloroform and 1,4-dioxane, were used to disperse MWNTs in PLA when preparing the solvent cast composites. Melt blended PLA-MWNT composites were prepared in a mini twin-screw compounder at a temperature of 165 °C. Samples from both processing techniques were characterized for thermal, electrical and mechanical attributes. Scanning electron microscope (SEM) results indicated that composites prepared using solvent casting had a better MWNT dispersion in PLA. In particular, 1,4-dioxane was considerably more effective in dispersing MWNT than chloroform. Composites prepared using melt blending contained large sized MWNT aggregates suggesting that greater shear mixing or more suitable MWNT surface functionalization is required.