Manipulating conductive network formation via 3D T-ZnO: A facile approach for a CNT-reinforced nanocomposite

Abstract

To achieve an efficient conductive network while preserving the properties of carbon nanofillers is a challenging and essential issue for the fabrication of highly conductive polymeric nanocomposites. The present paper reports a facile approach to manipulate the network formation in the polymer matrix via introducing the tetrapod ZnO whisker (T-ZnO) in the carbon nanotube (CNT)-reinforced epoxy composite. The influence of T-ZnO on the CNT dispersion was evaluated by UV-Vis spectroscopy, rheological measurement, scanning electron microscopy (SEM), and electrical and mechanical properties of the bulk composite. The results showed that the CNTs tend to disperse more uniformly with an increase in T-ZnO loading. An optimized ratio of 1:2 between CNTs and T-ZnO was found to significantly enhance the electrical conductivity by 8 orders of magnitude. A low percolation threshold of 0.25 wt% CNTs was achieved in this hybrid CNTs/T-ZnO composite, which is only 40% of the threshold value in the pure CNTs/epoxy. The flexural strength and modulus of the hybrid composite were also improved noticeably in comparison to the CNTs/epoxy. The mechanism for increasing the performance of the nanocomposite was analyzed. These results indicated that the T-ZnO can assist to efficiently improve the dispersion and the formation of the conductive network, which is beneficial to the enhancement of the mechanical and electrical performance of the nanocomposite.