Supercritical Fluids-Assisted Processing Using CO2 Foaming to Enhance the Dispersion of Nanofillers in Poly(butylene succinate)-Based Nanocomposites and the Conductivity

With the rapid development of electronic information technology, traditional metal conductive materials can no longer satisfy the needs of a wider industry. Poly(butylene succinate)/multiwalled carbon nanotubes (PBS/CNT) conductive polymer nanocomposites with varied CNT content were prepared by a HAAKE torque rheometer. The addition of CNT significantly improved the crystallization, viscoelasticity, and mechanical properties as well as thermal and electrical conductivity. Conductivity of the PBS/CNT nanocomposite with 5 wt% CNT increased from 8.23 × 10–15 S m−1 of pure PBS to 33.3 S m−1, an increase of 16 orders of magnitude. Moreover, the electrical percolation threshold $${\mathrm{\varphi }}_{\mathrm{c}}$$ of the PBS/CNT nanocomposites was 2.8 wt% and the critical index was 1.56, showing that the conductive network structure was between 2 and 3D and 2D network structure dominated. To further improve the conductivity, microcellular foams were successfully fabricated by batch foaming with supercritical fluids (scCO2). The electrical conductivity of the PBS/CNT foam with 5 wt% CNT reached 67.8 S m−1 and it was 104% higher than the corresponding solid nanocomposite.