Polylactide/multiwalled carbon nanotube composites – synthesis and electrical properties

Abstract

A procedure for the synthesis of polymeric nanocomposites comprising of polylactide (PLA) and well-dispersed multiwalled carbon nanotubes (MWCNT) (Figs. 3, 4) has been presented. The method involves the dispersion of the nanotubes in the PLA solution with the aid of ultrasounds and a rapid precipitation of the polymer composite in order to avoid reaggregation of the CNTs. The dependence of electrical conductivity on the content of the conducting phase for the polylactide composites containing various amounts of nanotubes obtained in this method was determined (Fig. 5). For comparison, composites with carbon black (Monarch 1100) were also prepared using the same procedure. The obtained PLA/MWCNT composites were characterized by low percolation threshold (0.25 wt. %) and a conductivity value of 5 · 10-² S/cm (with 1 wt. % of nanotubes). The obtained percolation threshold is ten times lower, and conductivity 100 times higher than in the case of respective composites containing carbon black. These differences were attributed to the high aspect ratio of the MWCNTs and their high conductivity.