Tailoring co-continuous like morphology in blends with highly asymmetric composition by MWCNTs: Towards biodegradable high-performance electrical conductive poly(l-lactide)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blends

The performance of polymer blends greatly depends on the phase morphologies and the incorporation of nanofillers provides a low-cost but efficient strategy to tailor the morphology and performance of immiscible polymer blends. In this work, we obtained co-continuous like morphology in poly(l-lactide) (PLLA)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) blend with highly asymmetric composition (80/20, wt/wt) through the self-networking behavior of multi-walled carbon nanotubes (MWCNTs). It was found that the electrical conductivity and the ductility of PLLA/P(3HB-co-4HB)/MWCNTs composites were enhanced at the same time compared with PLLA/MWCNTs composites. The percolation threshold of the prepared PLLA/P(3HB-co-4HB)/MWCNTs composites was 0.58 wt%, 36% lower than that of PLLA/MWCNTs composites and the highest value of elongation at break for PLLA/P(3HB-co-4HB)/MWCNTs composites was 226.4% when the content of MWCNTs was 1 wt%. The results indicate that MWCNTs can contribute to the formation of co-continuous like structure and our work provides a new way to prepare biodegradable high-performance conductive polymer composites with excellent conductivity and mechanical properties.