Selective distribution and migration of carbon nanotubes enhanced electrical and mechanical performances in polyolefin elastomers

Abstract

A thermodynamic and kinetic method based on the selective distribution and migration of multi-walled carbon nanotubes (MWCNTs) in polyoxyethylene (PEO)/ethylene-α-octene random copolymer (ORC) composite system was reported to improve the dispersion of MWCNTs in ORC. Scanning electron micrographs and transmission electron micrographs confirmed that MWCNTs could almost completely migrate from the PEO phase to the ORC phase during melt compounding and lead to tremendously improved dispersion of MWCNTs in ORC, compared with traditional melt compounded ORC/MWCNT composites. Rheological analysis revealed that better MWCNTs network was developed at a lower content of MWCNTs with an improved dispersion of MWCNTs in ORC. The percolation threshold was drastically reduced from 3.82 to 0.35 vol % and the electrical conductivity was tremendously improved. The mechanical properties were also fully enhanced in comparison with traditional melt compounded ORC/MWCNT composites owing to the homogeneous dispersion of MWCNTs. These results manifest that, by proper selection of components with a selective distribution of MWCNTs and controlling the migration process of MWCNTs in the composites, the dispersion of MWCNTs in polymer matrix and resulting performance of the nanocomposites can be greatly improved.