Influence of modification of MWCNTs on the structure and performance of MWCNT-Poly(MMA-AM) hybrid membranes

Abstract

Hybrid membranes containing multi-walled carbon nanotubes (MWCNTs) were initially prepared to separate benzene/cyclohexane mixtures. Subsequently, MWCNT surfaces were chemically modified using two methods to change the surface polarity of the MWCNTs and improve the distribution thereof in Poly(methylmethacrylate) (PMMA). This change consequently enhanced the separation performance of hybrid membranes with MWCNTs. Raman spectroscopy was used to characterize the structure of the pristine MWCNTs and the modified MWCNTs. The morphology and distribution of the MWCNTs in PMMA were investigated by transmission electron microscopy. The results showed that the addition of MWCNTs clearly improved the separation performance of the hybrid membranes. Surface modification introduced polar groups onto the MWCNT surface, which significantly improved the distribution of MWCNTs in the PMMA membranes and the performance of hybrid membranes. MWCNTs with higher surface polarity also increased the amount of MWCNTs distributed homogeneously in PMMA. Aminated MWCNTs (MWCNT-NH2) showed the highest surface polarity. Thus, the content of MWCNT-NH2 well distributed in PMMA was the highest among the three types of MWCNTs. The highest separation factor for the hybrid membranes with 1.0 wt% MWCNT-NH2 was about seven times that of membranes containing pristine MWCNTs. Copyright © 2013 John Wiley & Sons, Ltd.