Simultaneous ultrasonication‐assisted internal mixing to prepare MWCNTs‐filled epoxy composites with increased strength and thermal conductivity

Abstract

The uniform dispersion of carbon nanotubes in epoxy resin is one of the key factors to achieve the composites with desirable mechanical and physical property enforcement. However, the widely used dispersion methods have their own respective limitations in pursuing satisfactory nanotube dispersion. Herein, a new dispersion approach, based on the synergetic effect of combining high speed internal mixing with running simultaneously continuous ultrasonication treatment, has been proposed. The dispersion of nanotubes was carried out in a high speed internal mixer, consisting of twin kneading block structured rotors and an integrated ultrasonic horn, which was intercalated into the central position between the twin rotors. At first, the FEM simulation was conducted to optimize the kneading element assembly and illuminate the geometry influence of the ultrasonic horn intercalation on the mixing flow. Afterwards, to confirm the feasibility of the approach, pristine MWCNTs (P‐CNTs), oxidation modified MWCNTs (M‐CNTs) and M‐CNTs/multilayer graphene nanoplatelets (MGPs) hybrid are dispersed into epoxy resin. The dispersion of each sample in its liquid epoxy state is investigated under transparent optical microscopy. More characterizations, including SEM, TG/DTA, tensile test, and thermal conductivity measurements, were conducted on the cured composites. Competitive reinforcements on mechanical tensile property and thermal conductivity were observed. Especially, at a 1.5 wt% M‐CNTs/MGPs hybrid content, the composite mechanical tensile strength and thermal conductivity were 47% and 30% higher than those of neat epoxy. This preliminary study demonstrates the feasibility and practicability of the proposed approach to achieving good MWCNTs dispersion and distribution in epoxy resin. POLYM. COMPOS., 37:870–880, 2016. © 2014 Society of Plastics Engineers