Noncovalent functionalization of carbon nanotube using poly(vinylcarbazole)-based compatibilizer for reinforcement and conductivity improvement in epoxy composite

A new compatibilizer [P(GMA-co-VCz) copolymer] containing carbazole moiety and reactive epoxide group, which can functionalize multiwalled carbon nanotubes (MWCNTs) for making superior epoxy composites, was prepared by a simple one-pot free radical polymerization. The designed compatibilizer could noncovalently functionalize multiwalled carbon nanotube (MWCNTs) via - interaction as evidenced from fluorescence, Raman, and FTIR spectra analysis, and efficiently disperse MWCNTs in organic solvents. TEM images suggest a good wrapping of P(GMA-co-VCz) on MWCNTs surface. P(GMA-co-VCz) functionalized MWCNTs were more homogeneously dispersed in epoxy matrix than the case without compatibilizer, indicating that the compatibilizer improves the compatibility between MWCNTs and epoxy resin. In addition, the presence of epoxide groups in compatibilizer could generate covalent bonds with the epoxy matrix and improve the interface interaction between MWCNTs and epoxy matrix. As a result, mechanical and electrical properties of the epoxy composites with compatibilizer were largely improved as compared with those of composites without compatibilizer. The addition of as little as 0.15 wt % of MWCNTs to epoxy matrix affords a great increase of 40% in storage modulus and 52.5% in elongation at break. Furthermore, a sharp decrease of almost 9 orders of magnitude in volume resistivity of epoxy composite is observed. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45022.