Impact of carbon nanotube prelocalization on the ultra-low electrical percolation threshold and on the mechanical behavior of sintered UHMWPE-based nanocomposites

Abstract

Nascent powder particles of Ultra High Molecular Weight Polyethylene have been covered by multi-walled carbon nanotubes and then processed by means of sintering. The prelocalization of carbon nanotubes in the interfacial region between powder particles of UHMWPE allowed reaching an electrical percolation threshold as low as 0.04 wt%. It is also a possible way to reinforce specifically the interfacial regions with a very small amount of fillers. Indeed, the nucleation effect of the nanotubes is very strong on the strain-induced crystallization in the melting state of the composite. The tensile experiments above the melting point allowed by the extremely broad rubbery plateau of the UHMWPE show a significant increase in strain-hardening due to the addition of CNTs from 0.02 wt%. In the solid state the elastic properties, such as yield stress, and the crystallinity can also be increased for higher CNT concentrations despite the presence of aggregates which reduce the elongation at break.