Evolution of carbon nanotube dispersion in preparation of epoxy-based composites: From a masterbatch to a nanocomposite

Abstract

Abstract. The state of carbon nanotube (CNT) dispersion in epoxy is likely to change in the process of composite production. In the present work CNT dispersion is characterized at different stages of nanocomposite preparation: in the original masterbatch with high CNT concentration, after masterbatch dilution, in the process of curing and in the final nanocomposite. The evaluation techniques included dynamic rheological analysis of the liquid phases, optical, environmental and charge contrast scanning electron microscopy, electrochemical impedance spectroscopy and dynamic mechanical analysis. The evolution of the CNT dispersion was assessed for two CNT/epoxy systems with distinctly different dispersion states induced by different storage time. Strong interactions between CNT clusters were revealed in the masterbatch with a longer storage time. Upon curing CNT clusters in this material formed a network-like structure. This network enhanced the elastic behaviour and specific conductivity of the resulting nanocomposite, leading to a partial electrical percolation after curing.

Epoxy—MWCNT composites prepared from master batch and powder dilution: Effect of ionic liquid on dispersion and multifunctional properties

“…ER/CNT prepared from masterbatch (ER/CNTMB and ER/CNTMB/IL) (curves c and d) presented a Newtonian behavior, where the viscosity is independent on frequency. These results indicate that no re‐agglomeration process of the master batch used in the present work has been occurred, as discussed by Aravand et al .…”

“…The combination of calendering process and masterbatch approach has been reported to improve the dispersion of CNT within the epoxy matrix, as the increase in viscosity by using high amount of CNT requires additional shear forces, which is beneficial for dispersion . Some reports in the literature describe the use of epoxy/CNT as masterbatch to prepare epoxy‐based nanocomposites, which was either prepared in the lab or commercially available . Korayen et al compared the mechanical properties and morphology of epoxy/CNT nanocomposites prepared from powder and commercially available masterbatch and observed better mechanical properties and more homogeneous distribution of CNT when used in the masterbatch form .…”

Comparison of push-in and push-out tests for measuring interfacial shear strength in nano-reinforced composite materials

“…32,33 The masterbatch was diluted by factors of 17, 10, and 6 to obtain concentrations of CNTs in the composite of 0.3, 0.5, and 0.8 wt.%, respectively.…”

Stress magnification due to carbon nanotube agglomeration in composites

“…The high aspect ratio and hydrophobic surface of CNTs result in high surface energy that facilitates such agglomeration [8]. Moreover, in the course of the composite preparation these CNT agglomerates may further cluster into larger aggregates and networks [10]. Although in rare cases CNT agglomerates can be beneficial for the electrical conductivity as reported in [11], the general trend, however, is that they degrade properties of composites [12][13][14].…”