Novel electric conductive polylactide/carbon nanotubes foams prepared by supercritical CO2

In this paper, novel electric conductive polylactide/carbon nanotubes (PLA/CNTs) foams were fabricated by a pressure-quench process using supercritical CO2 as a blowing agent. The morphology of PLA/CNTs nanocomposites prepared by solution blending was characterized using SEM and the results indicate that CNTs well dispersed in PLA matrix. The introduction of CNTs improved the thermal stability of PLA. The morphology and electrical properties of PLA/CNTs foams were characterized and discussed. Depending on the process parameters, such as saturation temperature and pressure, nanocellular or microcellular structure of PLA/CNTs nanocomposites were obtained. The volume resistivity of PLA/CNTs foams was from 0.53×103 Ω cm to 15.13×103 Ω cm, which was affected by cell structure and crystallization of foams oppositely. Foaming reduced the electrical conductivity due to the decrease of CNTs volume content and the break of conductive pathways. However, crystallization increased the electrical conductivity possibly because of the CNTs structural change in which the CNTs were less curled and more connected.