Effects of surface modification of MWCNT on the mechanical and electrical properties of Fluoro elastomer/MWCNT nanocomposites

Abstract

Surface modification is a good way to improve the surface activity and interfacial strength of multiwalled carbon nanotubes (MWCNTs) when used as fillers in the polymer composites. Among the reported methods for nanotube modification, mixed acid oxidation and plasma treatment is often used by introducing polar groups to the sidewall of MWCNT successfully. The purpose of this study is to evaluate the effect of different surface modification of MWCNT on the mechanical property and electrical conductivity of Fluoro-elastomer (FE)/MWCNT nanocomposites. MWCNTs were surface modified by mixed oxidation and CF4 plasma treatment and then used to reinforce the fluoro elastomer (FE, a copolymer of trifluorochloroethylene and polyvinylidene fluoride). FE/MWCNT composite films were prepared from mixture solutions of ethylacetate and butylacetate, using untreated CNTs (UCNTs), acid-modified CNTs (ACNTs), and CF4 plasma-modified CNT (FCNTs). In each case, MWCNT content was 0.01wt%, 0.05wt%, 0.1wt%, and 0.2wt% with respect to the polymer. Morphology and mechanical properties were characterized by using scanning electron microscopy (SEM), Raman spectroscopy, as well as dynamic mechanical tests. The SEM results indicated that dispersion of ACNTs and especially FCNTs in FE was better than that of UCNTs. DMA indicated mechanical properties of FCNT composites were improved over ACNT and UCNT filled FE. The resulting electrical properties of the composites ranged from dielectric behavior to bulk conductivities of 10 -2Sm -1 and were found to depend strongly on the surface modification methods of MWCNTs. © 2012 Tao Xu and Jinghui Yang.