Understanding the mechanical and thermal property reinforcement of crosslinked polyethylene by nanodiamonds and carbon nanotubes

Abstract

A comprehensive investigation of the mechanical and thermal property reinforcement of silane-crosslinked polyethylene nanocomposites, containing small amounts of multi-walled carbon nanotubes (MWCNTs) and nanodiamonds (NDs), is presented in this work. Lower filler concentrations allowed a satisfactory dispersion, enabling the successful reinforcement of the matrix in every aspect. As the nanofiller content increased, the formed aggregates enlarged and the performance of the composites became more brittle. The measured stiffness enhancement of all the composites was found to be mainly influenced by the crystalline characteristics of the matrix and filler–matrix adhesion. Moreover, it was concluded that filler dispersion and filler–matrix interactions govern the ultimate strength and toughness behavior of these composites, which were found to slightly increase in minimum filler concentrations. Fractography was employed to study the embrittleness of the composites with higher filler loadings, and the observations revealed that a ductile to brittle transition is caused by a micro-deformation mechanism change in these composites. Furthermore, the prepared composites had a significantly improved thermal conductivity, which was mainly related to their superior specific heat capacity, while a great thermal stability enhancement was also revealed.