Influence of Waviness on the Elastic Properties of Aligned Carbon Nanotube Polymer Matrix Nanocomposites

Abstract

The promise of enhanced performance has motivated the study of one dimensional nanomaterials, especially aligned carbon nanotubes (A-CNTs), for the reinforcement of polymeric materials. While early work has shown that CNTs have remarkable theoretical properties, more recent work on aligned CNT polymer matrix nanocomposites (A-PNCs) have reported mechanical properties that are orders of magnitude lower than those predicted by rule of mixtures. This large difference primarily originates from the morphology of the CNTs that reinforce the A-PNCs, which have significant local curvature commonly referred to as waviness, but are commonly modeled using the oversimplified straight column geometry. Here we used a simulation framework capable of analyzing 10 5 wavy CNTs with realistic stochastic morphologies to study the influence of waviness on the compliance contribution of wavy A-CNTs to the effective elastic modulus of A-PNCs, and show that waviness is responsible for the orders of magnitude over-prediction of the A-PNC effective modulus by existing theoretical frameworks that both neglect the shear deformation mechanism and do not properly account for the CNT morphpology. Additional work to quantify the morphology of A-PNCs in three dimensions and simulate their full elastic constitutive relations is planned.

Interface engineering of carbon fiber composites using CNT: A review

“…For a system of aligned CNTs composed of MWCNTs with an outer diameter of around 8 nm, the waviness ratio significantly affected the elastic modulus with an increasing waviness ratio causing up to three‐fold decrease in the elastic modulus. The reduction of effective elastic moduli up to 100 times has been observed due to CNT waviness 42 …”

“…The reduction of effective elastic moduli up to 100 times has been observed due to CNT waviness. 42 Several works investigate growing CNTs onto the fibers, be it metal fibers like aluminium [43][44][45] or ceramic, 46 carbon 47 or glass fibers. 48 Some work also studied growing nanofiber on carbon fibers.…”