Electrically percolated nanofibrillar composites with core-sheath structures from completely wet ternary polymer blends

Abstract

Multiphase immiscible polymer blend systems have shown great potential to reduce the electrical percolation threshold for conductive applications. However, the material generally possesses poor mechanical properties since none of the polymer components can maintain substantially all of their original bulk properties, and also because coarse phase sizes are generally obtained due to the incompatible interfaces. In this work, a new technique to fabricate multiple percolated polymer composites through fibrillation of a completely wet ternary blend system composed of a matrix and two minor phases is reported. After melt compounding, polyethylene terephthalate (PET) formed dispersed droplets fully encapsulated by a conductive poly(ether-block-amide) (PEBA) layer in the polypropylene (PP) matrix. PET/PEBA nanofibrils with core-sheath structure and a typical diameter of 100–300 nm were then generated through melt spinning of the PP/PEBA/PET blends. The transformation of complex PET/PEBA droplets into high aspect ratio core-sheath nanofibrils significantly reduced the phase percolation threshold, allowing the development of conductive PEBA network structures at low minor phase (both PET and PEBA) contents to preserve the bulk properties of the PP matrix.