A low seepage threshold and super‐toughness of polybutylene succinate‐based composites with double percolation structure: Synergy of multi‐wall carbon nanotubes and polyvinyl butyral.

To obtain a super‐toughness and low seepage threshold for the conductivity of biodegradable soft polymer material, biodegradable polybutylene succinate (PBS)‐based composites with different contents of polyvinyl butyral (PVB) and multi‐wall carbon nanotubes (MWCNTs) were prepared by melt‐blending method. Synergy effects of different modified MWCNTs and PVB on the morphology, crystallization, and electrical and mechanical properties of MWCNTs/PVB/PBS composites were examined by Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), wide angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), polarizing microscope (POM), resistance tester, and universal testing machine. Compared with pure PBS, with increasing MWCNT content, the electrical conductivity of the MWCNTs/PBS composites showed an upward trend, and the percolation threshold for electrical conductivity of the MWCNTs/PBS composites reached 0.47%. The electrical conductivity of the PBS composite mixed with 1.0 wt% of surface modified MWCNTs slightly increased by one order of magnitude compared with that of pure PBS. By adding 20 wt% of the PVB and 1 wt% of the unmodified MWCNTs, the electrical conductivity of the MWCNTs/PVB/PBS composite increased by seven orders of magnitude compared with that of pure PBS. The percolation threshold for electrical conductivity of the MWCNTs/PVB/PBS composites decreased to 0.049% owing to the formation of double percolation structure. Furthermore, compared with pure PBS, when the PVB content was 20 wt%, and the MWCNTs was 1 wt%, the elongation at break and V‐notch impact strength of PBS‐based composite dramatically increased by approximately 300% and 12‐fold, respectively. [ABSTRACT FROM AUTHOR]