Effects of electrical fields in aligning SWNTs during production of polymer/SWNTs nanocomposites

Abstract

Single Wall carbon nanotubes (SWNTs) are distinguished by their exceptional mechanical strength and electrical properties. However, these properties can only be inherited by nanocomposites if SWNTs are strongly bonded, uniformly distributed, and aligned within the composite matrix during their manufacturing processing. Conversely, the limited availability and economical constraints presented by bulk manufacturing process of nanocomposite materials have been hindering factors in devising their utilization for structural applications and thus their commercialization.

This study is focused on the application of an electrical field to align SWNTs during the casting process of polymer nanocomposites where the experimental methodology is comprised of preparing samples exhibiting various percent weights of SWNTs in the polymer matrix while applying distinct electrostatic field strengths. Specifically, SWNTs are dispersed into a semi-crystalline polymer, poly (ethylene-co-vinyl alcohol) (EVOH) matrix. The resulting nanocomposites were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and tensile testing to evaluate their physical, thermal, and mechanical properties.

The highest electrostatic field strength used in this study (204V/mm, 60Hz) aligned low concentrations of SWNTs through the polymer matrix. Unfortunately, it also formed large agglomerations when using higher concentrations of SWNTs, and affected the tensile strength of the nanocomposite properties. The electrical field did not affect thermal characteristics, but the addition of SWNTs to the polymer matrix accelerated the melting of small crystals.